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What to look for in rebuilt gt40p

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    Posted: September-29-2017 at 6:57am
I have not looked for heads locally.
I read the hot rod gt40p how to guide and realized most of what they were discussing was for heads too fancy for what I need (1987 sn2001, family boat used for ski, wake).
I have read enough to get a general idea when I upgrade the cam (cam research)
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=5627
Performer intake, quick fuel m600 (if my rebuild and spec-to-80319 of my blistered 80551 fails to preform).

My plan was to chase down where my compression was going . If exhaust I would try to spin valves (it has run rich for awhile since the carb needs work). Engine is 1500 hrs. I neglected to do a wet compression test. These are warmed up, plugs out, throttle at idle, but cranked until it would raise no more. Oil pre is 20-25 at idle on mech guage (sender was out and new to me boat)

1: 115
2: 105
3: 125
4: 145

5: 126
6: 128
7: 120
8: 126

Has anyone ever ordered from these guys?
Do I need the max lift of .560 valve springs? Seems many have said too much spring press will ruin a cam. I have assembled a remanuf engine 20 years ago, but never built my own.
My thought was if the above plan shows weak heads, to pull the heads, inspect the cylinder walls, then decide if I can make it another year with new hwads, or if I need to repair this lower end or find a remanuf longblock to throw in and then one day build the orginal block up slowly.
Thank you.

https://m.ebay.com/itm/351W-FORD-GT40P-4-BAR-PAIR-OF-CYLINDER-HEADS-F77E-1-2-HEAD-BOLT-HOLE-/263172641468

This is for 2 rebuilt heads


These heads have 1/2" head bolt holes


WCC Heads are thoroughly cleaned and inspected

Pressure tested and/or magnafluxed to ensure no cracks or leaks in casting

Guide work performed / replaced with new guides or liners as needed

Three Angle Valve job performed

We also pull a vacuum on each valve to insure 

A perfect seal between the valve and the seat

All valves are reground or replaced with new valves as needed 

CBN milled to ensure straightness and correct finish

All machine work performed on the latest state of the art equipment

All parts are thoroughly cleaned and inspected before assembly

Heads are assembled with new valve seals and brass freeze plugs


VALVE SPRING UPGRADE AVAILABLE    MAX LIFT .560

ADDITIONAL COST OF $120

SEND MESSAGE WITH ORDER 

AND WE WILL BILL YOU SEPARATELY THRU PAYPAL

 

     NO CORE CHARGE

 




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outerbanked View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote outerbanked Quote  Post ReplyReply Direct Link To This Post Posted: September-29-2017 at 7:21am
https://imgur.com/a/NtIoD
I had to cut the garage door tracks and remove the door moldings. Will not work for everyday parking, but will work for winter.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: September-29-2017 at 7:49am
Originally posted by outerbanked outerbanked wrote:

https://imgur.com/a/NtIoD
I had to cut the garage door tracks and remove the door moldings. Will not work for everyday parking, but will work for winter.

Link


54 Atom


77 Tique

64 X55 Dunphy

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Duane in Indy View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: September-29-2017 at 7:57am
Another alternative for the heads would be going to a set of Flo Tek heads that Speedway Motors sells. They are machined in Evansville Indiana. They are aluminum and have 58 cc chambers. I am running them on my engine and have been satisfied with their performance and the fact that you will shed 40 pounds. Dollar for dollar they are a good value.   Something to think about.





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SNobsessed View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SNobsessed Quote  Post ReplyReply Direct Link To This Post Posted: September-29-2017 at 10:44am
A leak down test will tell you what is wrong & is a lot easier than pulling heads for inspection.
“Beer is proof that God loves us and wants us to be happy.”

Ben Franklin
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outerbanked View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote outerbanked Quote  Post ReplyReply Direct Link To This Post Posted: September-29-2017 at 1:36pm
SNobsessed,
I agree, my plan was a leakdown and listen first, followed by spinning the exhaust valves [if I'm lucky]. My post was not clear on that.
I have been looking at heads and intake and will look at the flo tech. I have a lot more research time than "work on boat by myself" time.
Thank you.
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KENO View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: September-30-2017 at 12:40pm
I've had no problems with the GT-40P heads with the normal springs and a cam with a little more lift than stock (in the .460 range)

Never dealt with the place you refer to, but Dreaming on this site has recently gone through some engine issues and dealt with a place in Spokane and he liked what he got.

Here's a link to one of his threads, he's probably an easy drive from you since he's in Tacoma and could tell you his experiences. You could send him a PM.
link

Since the 351 has "free spinning valves" from the factory, I'm not sure what you expect to get from an "exhaust valve spin". It doesn't have positive rotators but they are described by Ford as free spinning.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: September-30-2017 at 2:48pm
Dreaming ordered his rebuild from S&J in Spokane.
There is also a shop in Spokane named Motor Works.
Either one could rebuild a set of heads for you if needed or do the entire engine.
They can rebuild your engine or give you an exchange.   Dreaming would have a better idea of what they would charge. I think he upgraded his when ordered.
There is also a large re-builder in Bellingham WA. Yamato I believe is the name.
Any of these are professional shops that work on schedules so you will get your parts back when they say they will if time is an issue.
I just did a valve job helping out a friend, a Jeep 4.0L, we dropped off the head on a Tuesday morning and got it back Friday afternoon, had it running again on Saturday.
Not a big deal if you only need a valve job. We used a local machine shop that did all the things advertised on the ebay site you listed. That is all standard rebuild items they are listing that any competent shop will give you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: September-30-2017 at 2:50pm
Duane, good looking engine, can I ask how much power/speed you picked up with the new Aluminum Heads?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: September-30-2017 at 3:19pm
Originally posted by MrMcD MrMcD wrote:

Duane, good looking engine, can I ask how much power/speed you picked up with the new Aluminum Heads?


Mark, Good question but hard answer..   I did a complete engine rebuild at the same time as the head swap. Bored, pistons, cam, port/polish, carb, intake. Total blueprint job. At the same time I re-gelled the deck and hull. New stringers with out foam. Got rid of a lot of weight. Follow my "Mustang 17 Rebuild" thread in the general section sometime.
Pre rebuild I was only getting about 45 mph. Now pushing 60 mph. gps @ 5400 rpm.
I feel confident that the heads play a big part. Remember with these relatively low rpm, high torque engines you want small chambers (compression), small ports and small valves to produce the effects that we are looking for . Just the opposite of drag race high rpm motors. JMO, others may vary.    Duane
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: September-30-2017 at 4:23pm
Thanks for the update Duane.   Wow. 60 in a Nautique is rarified air for sure.
I swapped heads on my 78 351W 25 years ago. Similar update, I used a set of 289 Hi Po heads, smaller chamber size for more compression, I think I was at 10.5, had larger valves and fully ported and polished. It really woke up that 351. I did not have GPS but did see 50+ MPH in the 78 Ski Nautique. Mine would just start to porpose on smooth water wide open. I know it would gain about 200 RPM after the speedo hit 50 so maybe 53-55. Not 60 for sure. I used a 13 x 14 on it back then. 60 mph is pretty cool.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote outerbanked Quote  Post ReplyReply Direct Link To This Post Posted: October-02-2017 at 4:48pm
Keno, too much you tube and not enough manual reading I guess. I now know that valves spin. I had seen a video of someone cleaning up exhaust valves by presurizing the cyl and spinning the valve. This was done without valve grinding paste, and with the cyl head installed. Seems too magic now, but at the time.. My mind starts to hunt for a solution to a problem I do not have. I am not able to hop out my back door and start up the boat, nor drive it to work like a project car. I still have not had the time for a leakdown test to tell me where the air is leaving the system.
Thanks for the responses.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Shep72 Quote  Post ReplyReply Direct Link To This Post Posted: October-04-2017 at 2:03am
I used eBay. Seller was windycityengineandparts gt40p heads with 1/2" bolt holes. $475 +$134 shipping. I didn't like one of the heads he sent and he sent another with return shipping for the one I didn't like. Cam was a barebones by Lunati. I did upgrade to dual springs recommended for my cam. Did some shimming to get proper spring compress height and a couple of rockers for proper preload. (Common on rebuilt heads). So far I have zero complaints. Also did the dui ignition in place of pro tech.
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