DOOE heads

gary if your just going to bolt them on no it's not worth it, if you spend a little and replace the exhaust valves then maybe, that's D0OE's to GT-40's. I was under the impression that one boat already had the gt-40's and you where working on another boat motor. I would take a look at the other boat motor that you think has D0OE too and make sure because if they aren't then a direct bolt on that one would be an improvement. The week link is the 1.45 sized valves on the D0OE's they need to be 1.60. alot of the auto guys use 2.02/1.60 valves in the D0OE's but thats pretty crazy and really tight and requires new pistons as well, 1.94/1.60 are about as large as you can go and they almost touch but don't and you can use stock psiton's. The 1.74's on the intake side are fine just not the 1.45 on the exhaust.

Chris...here's what I'm after! On the orange SN...I just want to get a bit more performce with out major $$$ spent! The 72 mustang has the gt40's(low hrs) on it now...those heads could go on the SN along with a better allum. duel plane intake(edelbrock performer or typhoon)and give me better than stock! The mustang could get the SN heads(what ever they are)or the D0OE heads.

Also...I will need to pull the engine on the SN soon(it needs the rear seal changed). I want to do a compession check first and after it's out inspect things to see what shape it's in...it seems to run well , but that would be a good time to do something if it soon would need any work! If the engine is tired I might as well have a fresh rebuild (balanced too) to go with the better heads and intake! If I am going to drop $1000-$1500.00 I would rather spend it on a fresh bottom! The 302 block I have sitting in the garage is in great shape...if it's better than the one I am pulling...then it could be the one to rebuild!
I will know in a few weeks!

Anyway...I think I have the answer for what to do regarding the heads! No real point spending the cash on the D0OE's!

Thanks for the that info. and of course the entertainment

Chris...very good advice! Thanks!

And...I even got the info I was after!

Jim In Houston,thanx for the pics,glad to see some of these old babes doing what they do best,give us joy,and to pa$$ iy on to our grandkids is priceless............what bayou are you on and where does it run to? i am about flamed out,just too old to take things seriously anymore.and i agree we all lost at that war....Ain't it fine to live on a bayou,did not think ya'll had that kind of boating over there,think of LA. bayous,cypress trees & alligators. Think of Texas cowboys,oilwells Lake Texoma,got a beautiful place there........ boat dr

cool boat too,and your choice of babes (grandkids are too cool)

   While on the subject of roller rockers,I was just wondering if any of you that use them have ever seen them damage the top of the valve stem?I've seen it happen on a big block chevy,and I see it all the time on V-twins.These are actually roller tipped rockers,not the full fledged "rollers".Not a boat question,I realize...just curious.

      Mike

Not centered over the tip due to the wrong length push rods/ bad adjustemnt, etc will mess up a valve stem but you should see less wear in general than the stock ones. Going a little more extreme on the ratio than stock can of course add some stresses as well. As for HP increase I don't really know because I put on new heads, exhaust, and ignition at the same time I changed rockers...

Jim_In_Houston wrote: Maybe there is an M.E. on the site that can convert 15 HP to BTUs of heat.

There will be soon. My buddy in TX just bought an '86 BFN and is picking it up tomorrow!

TRB..am not a M.E. but a search shows this conversion...15 hp =636.6 BTU/min. or 38196 BTU/hr. my feeling on this subject,if GM & FoMoCo were doing the same math there would be roller rockers on all production motors,a savings of energy,torque or heat would drastictly increase hp and an added 1 or 2 mpg.why aint they using them,roller lifters are the only change they have made,and i think that the reason for that was the heavy metals being removed from the oils(lifter failure) imho...........boat dr

At 0 RPM I think you would be dealing with static friction once moving kinetic friction. The difference is probably negligible in the case of the rollers due to the very low contact area. However, with the standard ball and socket rockers it definitely takes a little more umphf to get them going. I have turned over both setups with a 18" breaker bar and they are significantly different in feel, I would say ten pounds of pressure difference is completely possible but I feel that test was biased against the standard rollers precisely because I am not able to smoothly turn the a$$embly over more than a couple degrees so its hard to overcome the static friction and get a stable feel of if after haveing to yank it to get it going. I think the lack of oil pressure is going to hurt the stock rockers more. But it is much easier, at least from a stop to turn the rollers.

As for production cars using roller rockers I think you find them on most mid nineties to current chyrsler 1.8 and 2.0 SOHC and DOHC engines (they are itsy bitsy but they are in there), the Acura RSX since 2003 when the turned the engine around, corvettes since the intro of the LS4 in maybe 94?, and the most popular production application is the GM/Isuzu Duramax Diesel I am sure there are more particularily with the little overhead engines.

I have a friend that runs a portable dyno business. I will ask him to look out for someone coming in to test the results of a roller rocker upgrade. Too bad that its a cha$$is dyno or I would be able to settle a lot of these boat motor performance quandrys a little more definitively since I seem to have these motors out every season...

Jim and Joe in NY,here is a good phone# 586-468-1356 Ford Motor Racing(tech dept.) ask for Ray,he is a text book of knowledge on who,what when and where of small block Fords.most of my build info for my 331 came from his research and personal know how. just got off the phone w/him about the roller rocker issue,and here is what FoMoCo racing says....... our engine dyno shows no additional HP nor Torque gains or if so were so small to substantiate the cost,this is stock ratio rollers vs. stock stamped steel on the GT-40 heads.

boat dr

Jim,
here is my build:
1993 302, bore .030 add SRP flat top pistons add 1 Eagle rotating a$$y. 3.25 stroke, balance 50 oz. flwheel after you make it a 28 oz. notch cyl. (for clearance of the rod bolts)add good GT- 40 heads(64cc)good Cam Research bump stick,Edelbrock intake.add tender loving care ,stir well=350 plus HP and the reason for the trouble and expenseis 400lb. ft. Torque......... boat dr

Dr. Iwas watching a truck show over the weekend and seen a 302 with a 348 or 349 stroker kit . They said it had 400 hp . Have you heard anything about that?

Pat

p/allen the 331 and the 347 are the most popular builds,331 seem to have a longer life span tho,

Jim.. there is a counter weight cast into the flywheel,this is either a 50 oz.(old stuff,2 piece rear main seal ) or 28oz.(new stuff,1 piece ).

Joe, we used the orig. h/b, the flywheel had to be drilled,most cost effective method.H/b is the same not marine specific,flywheel the same.could have used new style but was not sure till we sent it to the engine builder. 2 piece rear main seal used the 50 oz.the concern was the bolt pattern for the dampner,which by the way is the same as the pressure plate,no diff.other than the weight diff. The harmonic bal. does not know rotation,nor rotating a$$y. have a TCI,rattler dampner,took it off in favor of the timing marks and their proper location,no tape.your dampner controls vibration andthe angle of crank twist,not the overall balance of the rotating a$$y.........boat dr