GT40 head question
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=9031
Printed Date: September-26-2024 at 8:17pm
Topic: GT40 head question
Posted By: alph
Subject: GT40 head question
Date Posted: November-21-2007 at 1:11pm
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I've got an 86 Martinique that I've been trying to modernize a bit. I've got about 2000 lbs of integrated ballast in it now, but I had it out the other day for the first time riding behind it and it felt under powered to me.
I've got the acme 542 prop on it, so that's not it. I think my motor is tired. Is the GT40 swap just a simple bolt on for the 351? Do I have to have PCM GT40 heads or can I get heads off of a 5.0 and slap them on? Or better yet, can I put the aluminum heads from my old 65 stang on the 351 block? For some reason I remember somebody telling me that wouldn't work because of deck height. Any feedback would help greatly. Thanks. |
Replies:
Posted By: TRBenj
Date Posted: November-21-2007 at 1:28pm
If you havent already, give the boat a tune up before you start replacing parts. Proper timing, a well-tuned carb, and new cap/rotor/plugs/wires will improve performance and reliability.
Yes. GT40p's are better and cheaper though.
Automotive heads are fine. Bolt holes will have to be drilled out to 1/2" when installing 302 heads on a 351w.
Big debate as to whether or not aluminum heads are a good idea on a RWC motor. Do your research and decide for yourself. Any 289/302/351w heads should bolt right on. ------------- |
alph wrote:Posted By: alph
Date Posted: November-21-2007 at 2:10pm
| So GT40p's are PCM heads? |
Posted By: TRBenj
Date Posted: November-21-2007 at 2:23pm
http://www.stangpro.com/html/articles/gt40p_files/gt40p1.htm - No. ------------- |
Posted By: alph
Date Posted: November-21-2007 at 3:35pm
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I had a friend recommend the edelbrock carb, so I put that on. Plugs and plug wires are all brand new. Rotor isn't. I'll check on that. Carb was freshly tuned so that's not it. I'm pretty sure timing is dead on.
The last time I did a compression check each cylinder was completely random. I'm figureing I've either got some valve issues or some ring issues. thoughts? Thanks for the input on the heads. |
Posted By: TRBenj
Date Posted: November-21-2007 at 3:41pm
What do you mean by "completely random"? If your methods were solid and the cylinders varied by more than 10%, Id do a leakdown test. That will tell you if new heads will solve your compression issues or if you should save for an engine rebuild instead. ------------- |
Posted By: alph
Date Posted: November-21-2007 at 4:38pm
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Random ranged from 125 to 75 on one side of the engine.
How do you do a leakdown test? |
Posted By: TRDon
Date Posted: November-21-2007 at 9:59pm
cant just get them off of any mustang, has to be a 93-95 cobra or a 95-96 explorer (GT40P) Other mustangs had (for 87-93) the E7TE head which may be better for performance, but isnt worth the swap IMHO. If you have the tools and skill to port the E7s then it may be worth it. Ski dim sells the heads for an astronomical price, you can go on corral.net and get a set of used for under 500 shipped vs ski dim that have them for over 1 grand a piece ------------- 85 2001 351 240hp FS 93 sport |
Posted By: nuttyskier2002
Date Posted: November-21-2007 at 10:47pm
A true leakdown test requires a special tool to do properly. The tool is a small manifold made of pipe fittings, gauges, an air pressure regulator and hose and is supplied compressed air. There are two pressure gauges (0-100 psi range) which are separeted by an orifice that meters the airflow supplied by the compressor (shop air). The regulator is set to 100 psi (indicated by the first gauge). Air flows through the manifold and feeds the first gauge and the orifice. On the other side of the orifice is the second gauge and a fitting that will screw into the spark plug hole of the cylinder under test. With the piston set on the compression stroke (both valves closed), the regulator set to 100 and the outlet of the tool (spark plug fitting) feeding the cylinder... you compare the readings between the first and second gauge. Readings should be within 10% of each other. The closer the second gauge reads to 100 the better. Now, if you have a leak, you can listen and detect where the air is going and narrow down what is wrong (if anything) with your engine. I know this is rather lengthy, but it is a good test because you can often isolate where the problem is. If there's something you don't understand and like further explaination....write back. Hope this helps. Brian ------------- 95 Malibu Echelon w/Mercruiser 350 Magnum Skier Former boats: 88 Ski Centurion Tru Trac II 59 Chris Craft Capri (woody) |
Posted By: alph
Date Posted: November-21-2007 at 11:35pm
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Brian, that does make sense. Thanks. Where can I get one of those tools?
Is that one of those rentals, or would I have to buy? |
Posted By: nuttyskier2002
Date Posted: November-22-2007 at 1:43am
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Here's a link to one that I found on line: http://www.powerhouseproducts.com/catalog/Images/2006pdfs/ph26.pdf Scroll to bottom of page.
Also try NAPA, Snapon or Mac Tools. I pieced one of these things together one time about 10 or 12 years ago. The critical part is the orifice size between the two gauges. I don't remember the size though. If you get it wrong your readings will be off. ------------- 95 Malibu Echelon w/Mercruiser 350 Magnum Skier Former boats: 88 Ski Centurion Tru Trac II 59 Chris Craft Capri (woody) |
Posted By: Gary S
Date Posted: November-22-2007 at 2:22pm
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Google leak down tester, all kinds of info there including how to make one. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: jbear
Date Posted: November-23-2007 at 12:31am
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Gary: You didn't work and grab some of that double-time and a half?
john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: Gary S
Date Posted: November-23-2007 at 11:10am
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John- No,Son home from school,and since we lost Mom this summer,Dad home for 1st time in 20 yrs.Just got rid of same boss I had for 4 yrs who thought quanity was more important that quality,so I haven't worked much ot in last 3yrs.As you get older there are some things that are not as important and others you will not tolerate, but you know that. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: jbear
Date Posted: November-24-2007 at 2:58am
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Most every boss in my last 10 years had the same attitude. Funny...they kept coming and going and guys like me just kept on doing the job our way. Wonder what that meant.
Know exactly what you meant as to the importance of somethings. And as to the ot...always worked lots...don't have any of that money left...wish I'da spent just a ittle more time at home on the weekends and evenings. Life really changed for the better when I swore off the ot my last few years...didn't miss the money either. Have found out here latrly that you can life on lots less...you'll find out soon. Then you can come and visit. alph; sorry for the thread jack. ReidP found me a set of GT40p heads at a very reasonable price and I love 'em. He'll have to chime in as to where he got them...I forgot...but I think they were from here in Florida. john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: Gary S
Date Posted: November-24-2007 at 3:07am
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I think someone here steered me here
http://www.tristatecylinderhead.com/catalog/product_info.php?products_id=40&osCsid=13ee3e943670cdd4daf9d981cc52152d John,did you actually notice a difference? Reid was talking heads with me when I was trying his props.There would be a reason to work some OT! ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: jbear
Date Posted: November-24-2007 at 3:54am
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I think mine came from Clearwater Cylinderhead...but not really sure...Reid would remember. And yes...in combo with my new Performer manifold I bought from nuttyskier on here I noticed a big difference. Was very happy with the upgrade. There was a thread from when the guys put everything on for me complete with pictures but I don't know how I would go back to find it and link it for you.
john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: nuttyskier2002
Date Posted: November-24-2007 at 4:29am
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John, that intake is actually a Power Plus Typhoon by Professional Products. The P/N is 54023 for anyone who is interested in purchasing one. They are the most reasonable priced Ford intakes (when buying new that is). ------------- 95 Malibu Echelon w/Mercruiser 350 Magnum Skier Former boats: 88 Ski Centurion Tru Trac II 59 Chris Craft Capri (woody) |
Posted By: Gary S
Date Posted: November-24-2007 at 12:24pm
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I remember reading it,but forgot they were P's ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 79nautique
Date Posted: November-24-2007 at 12:41pm
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I have a 54024 the chrome version, new in the box, for sale if anyone is interested. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRDon
Date Posted: November-24-2007 at 12:55pm
it is a knockoff edelbrock performer cast in china. The casting quality isnt nearly as good as a edelbrock. It is a great piece for the money and if you put a couple hours in with a dremel or air grinder to clean up the casting flash, it is even better value. ------------- 85 2001 351 240hp FS 93 sport |
Posted By: 79nautique
Date Posted: November-24-2007 at 1:19pm
I would disagree with you completely. The intake we installed on Johns had no flash issues, and the Chrome version I have is flawless, both castings are equal to the Edelbrocks and the professional products design is much better in several area's. so are you talking from personal experince or quoting BS from a book/magazine because it sure doesn't sound like you have ever held a professional products intake in your hands. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: TRDon
Date Posted: November-24-2007 at 7:15pm
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WOW. That was pretty accusational. I play with fords a LOT and I am part of the local mustang club and i help manage their forum board. I have done a lot of work on my car any other peoples cars in the club over the past 4 years. I have seen plenty of intakes and played and installed several. I have done a lot of porting work on intakes and am dabbeling a bit in heads now too. What I write on forum boards isnt just to say what I have heard or read on frivolus websites but what I have personally experienced. There is, in what I have seen with my own 2 eyes, more casting flash and a more porus sand used in the casting process of the PP intake than the edelbrock. I never said it was a problem, I just said there is more there than the eddy. The PP is not better in any area than price because it is based off of the performer design. It is cheaper because it is made in china and that is the difference in price.
So let me ask you this in rebuttal, have you ever held an edelbrock piece in your hands or are you quoting BS form a book or magazine. Thanks for hammering me and acting like a jerk like I have no clue. Im not some hopped up 18 year old who never seen an engine before, but you are quick to assume that. I never once it was junk or said anything negative to justify a comment like that form you. ------------- 85 2001 351 240hp FS 93 sport |
Posted By: Jim_In_Houston
Date Posted: November-24-2007 at 8:02pm
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Hmm... I'm speachless. But, as far as hammerings from 79 you ain't seen nothin' yet. That was pretty mild. Just wait until he's off his medication. So, do they have hot rods and racing in China? You never know about the world anymore. That Chinese company could be owned by Edlebrock and the minute they close their USA plant the Edlebrock name will start showing up on the Chinese castings. You never know... I wanna be a Grand Poobah too. And Edelbrock, if that's not your plant I'm totally sorry for the slanderous comment - don't sue me, it was only wild and crazy speculation from a guy setting near a bayou on a cold an rainy day with a glass of Turkey and 7-Up. I have no facts. ------------- Happy owner of a '66 and a '68 Mustang |
Posted By: jbear
Date Posted: November-24-2007 at 10:27pm
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Wow again. J-I-H and 79 are rolling into holiday form.
Actually guys...you all know how clueless I am. Thanks Brian for clearing up just what I have. And thanks again for getting it to me at the right price. As 79 said...when it went on it looked great and performs the same way. john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: Jim_In_Houston
Date Posted: November-24-2007 at 10:38pm
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Hey jbear. Actually, from Thanksgiving to Christmas is the only time I drink hi balls (bourbon and soft drink over ice for all you kids out there). It's a religious thing with me.
When did auto spell checker show up on this thing???? Don't tell me it's been here all the time - I'm all ready losing my mind. I think because the '68 did not make it into the water one time this year. Not one time! It's been a crazy rainy year down here in Southeast Texas. ------------- Happy owner of a '66 and a '68 Mustang |
Posted By: jbear
Date Posted: November-24-2007 at 10:46pm
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Jim; Thanksgiving to Christmas is the only time I don't do Beam and Diet Coke. Something about the Holidays.
Spell check has been here for awhile. Haven't you noticed how it cleaned up 79's posts. Used to be only us guys who knew him could make out some of his posts...now everybody can understand him. Very bad that the '68 never got wet. I remember some of your posts with pics of the spring flooding...just kept it up all summer huh? john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: 79nautique
Date Posted: November-24-2007 at 11:07pm
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spell check, where? why?
actually I installed a performer on mine, when I replaced the motor and I bought a chrome PP. liked the extra water passage, and what looks to be less porting work too. Was going to use it with the DO0E heads I had reworked. But there both sitting in a box now. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 87BFN owner
Date Posted: November-25-2007 at 11:56pm
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Jbear this should be the link your looking for.
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=5765&KW=jbear - jbears upgrade ------------- |
Posted By: 79nautique
Date Posted: November-26-2007 at 12:52am
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notice all of the flashing on the casting by the way. Oh and you only get flash on molded/pressure cast/formed materials, like die casting or plastic injection molding. Green sand molds equall no flash ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: jbear
Date Posted: November-26-2007 at 1:58am
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Jim: thanks for the link.
I am always amazed at how easy you guys make some of this stuff seem. john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: boat dr
Date Posted: November-26-2007 at 2:44am
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JBEAR< It's called YOUTH............ ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: jbear
Date Posted: November-26-2007 at 2:47am
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To bad they save youth for the young...I could make such better use of it now that I finally know what is goin' on.
john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: boat dr
Date Posted: November-26-2007 at 11:45am
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As I have said before Youth is wasted on the young and wisdom on the Old..........
I assume you and the Mrs. enjoyed lots of blessings on Thursday,Karen and I were more blessed than we needed.........Good friends , good food and a warm place to lay my head. Bird Season is open, the dogs are eager to hunt and I need a vacation from this shop............. ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: Riley
Date Posted: November-26-2007 at 1:58pm
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I wished I lived a little closer Boat doc, I'd love to see your dogs hunt. ------------- |
Posted By: 87BFN owner
Date Posted: November-26-2007 at 3:12pm
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Jbear
Do not feel bad I just learned how to post the links. I didn't know how for quite sometime. Boat doc I know how you feel deer season has been open since the 15th and I have only been out once. I am shooting for making it out a couple times this week. No pun intended. ------------- |
Posted By: jbear
Date Posted: November-26-2007 at 10:52pm
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I'd like to see them too...dr I think you remember I had a Springer...did not hunt tho. But I would love to see a pic of your guys.
john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: horkn
Date Posted: March-20-2008 at 1:56am
93-95 cobras had cast iron GT40 heads. 96.5- 02 IIRC explorers and the mercury version of the explorer that ahd 5.0 fords all had GT40 P heads, and those are a great choice for an inboard. I am looking for a set myself. and I will def go used, and have them rebuilt. 87-93 gt and lx 5.0s and 94-95 gt mustangs and GTS mustangs had E7TE heads. If anyone want a set of 120,000 mile 87 E7TE heads I have a set, but I really dont think there is much of a gain to drop those ona 351W PCM 240hp motor. there would be some gain, but not as much as the GT40 or GT40P heads. If you were to have the E7TE's "power ported" then they would be better than a stock set of iron GT40's. for what DIM sells their GT40's for I am shocked. and they are reg GT40's now, and not the P's. Tristate has sets of rebuilt gt40ps for 700 dollras,a nd I think that isstill too much. I bet I can find a used set of p heads for 100-150 and have a valve job done, totalling under 500 dollars. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: MaddMarxx
Date Posted: March-20-2008 at 3:00am
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Try (clearwater cylinder head) they have about the best price around for P-heads I think they are around 400 bucks! ------------- |
Posted By: jbear
Date Posted: March-20-2008 at 3:16am
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And I gotta say those p-heads from Clearwater work very well...right MM?
john ------------- "Loud pipes save lives" AdamT sez "I'm Canadian and a beaver lover myself"... |
Posted By: Gary S
Date Posted: March-20-2008 at 2:16pm
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I checked with Clearwater about 2 weeks ago. New are 260 ea and rebuilt are 175 ea. Shipping is 25 ea. 2 year warrantee on rebuilt and 3 year on new. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: TRBenj
Date Posted: March-20-2008 at 2:44pm
Their price has gone up over the last year or so, but dont forget that they also install upgraded valvespings (good to .550 of lift), which is really a weak point on the stock P's if youre adding a cam. A good set will run you upwards of $130 plus install, so that brings the price right in line. I went the same route youre propsosing (bought used, had a VJ done) and if I were to do it again, I would go with Tristate. Just my 2 cents. If youre not planning on upgrading valvesprings, go with Clearwater- I dont see another way to get a complete set of rebuilt heads for $400. P's started being installed in Explorers in mid-97, I believe. Up to that point, 5.0 Explorers had GT40 heads, if my memory is correct. ------------- |
Posted By: 81nautique
Date Posted: March-20-2008 at 2:47pm
Tim, Not only has their price gone up but when I bought mine about 1 1/2 years ago they were new castings, they seem to only show rebuilt now. ------------- You can’t change the wind but you can adjust your sails |
Posted By: Gary S
Date Posted: March-20-2008 at 5:55pm
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I talked to them too,they are rebuilt ones.He also said they had gone up and did not even know that there was a price on the web site.Anyway they are at 599 a set and 25ea for shipping.
When I talked to Clearwater they told me that the new castings are not done by Ford and they are now stronger in areas that needed it. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: MaddMarxx
Date Posted: March-20-2008 at 8:28pm
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We put a set of the Clearwater rebuilt heads on "Jbears" boat last year along with an intake and it picked up 5MPH, it went from 45 to around 50+ MPH and thats without a cam, not bad! ------------- |
Posted By: horkn
Date Posted: March-20-2008 at 9:19pm
thanks for the "heads UP" on the heads ;) I need a good place to geta set of P heads to pep my martinique up. :) ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |
Posted By: horkn
Date Posted: June-20-2008 at 7:50pm
Ok, I have come back to this thread becasue I acquired a set of used GT40P heads off of an explorer, and I got my performer intake for My b day in March, and now I will be installing these this weekend. Pre 96 5.0 explorers until mid 1996 had normal GT40 iron heads. The 1996.5- 2001 explorers had the GT40P's. 87-93 e7Te mustang heads are a much better head than the stock heads on non gt40 351s. I have a complete 302 HO from an 87 5.0 mustang. But the gt40p heads are better than the e7te's in stock form. If you port a set of e7te's, you can get more power than with a set of stock gt40ps, or GT40's The gt40P flows more than the gt40 iron head stock. The P heads are nice for boats since for car use, the headers either need to be replaced, or hammered in to fit. The plugs are in the wrong spot for auto use. Good news for us marine guys.:) My P heads I got for 199 dollars, and had then 3 angle valve job, and head bolt holes enlarged to fit the 351w from the 302 it was on. They were also decked .60 to true them up, and had new brass plugs installed. With a full gasket kit for my pcm 351, it was 600 dollars total. My p heads came off of an explorer that should not have had P heads, but iron gt40 heads. It was made a few months before they were supposed to have had P heads, which is why I got them for 200 dollars. The guy wanted iron gt40 heads form the early Explorer for use in a mustang, so it worked for me. So, off I go to rip the old heads and intake off,and put the new upgrades on. I am certain I had a leaky intake manifold gasket/ seal. So hopefully this will cure my running issue that came up last year. And it wll give me a nice shot of HP as well:) I bought a Mr gasket 1932 adapter to mount the holley 4160 to the edelbrock performer intake, so hopefully it fits. I am guessing I will need a shorter flame arrestor, but that will be minor after I get all the rest of the top end done. ------------- 78 martinique- refloored, reinforced, stringers re glassed, re engineered interior GT40P heads Edelbrock Performer intake acme 4 blade http://img.photobucket.com/albums/v64/horkn/fish/nautique.jpg |