I just picked up a fresh set of F3JE heads for cheap and was wondering what kind of performance potential theses have. I know they are a marine head but that's as much info as I can find.

 

Ford Mustang Forums : Corral.net Mustang Forum - View Single Post - cc on GT40 heads

 

F3ZE heads flow about 30% better than E7TE heads and if you were to bolt them on your '81 302 you would gain about 1 point in compression ratio.. 8.2 to 9.2:1. Add a mild cam and headers and you could have a 300hp motor.

 

The info posted by Oldman indicates that the heads I have are functionally the same as the F1ZE. The plan is to do a simple gasket match and grind out the thermactor bumps and bolt em on inplace of the D6s I have now and stab in a new cam.

Conanski, what would be the approximate CR be with my current flat tops.

 

You have flattop pistons in this motor.. meaning it's not stock?

 

Just about anything should be an upgrade from D6s... lol

edit: I have a set of D6s covering holes to keep critters out from under my house... lol

 

Correct, the short block was purchased from a local guy and had been recently rebuilt with forged flat tops. Three years ago my plan was to put a SBF together for the '81 but my wife got pregenant so I tossed on the D6 heads and 2 barrel intake.

 

Ok so existing compression ratio with D6 heads wouldn't be quite a low as it would be with the stock pistons but the end result with the GT40 heads will be about the same or around 9.2:1.

P.S. Don't gasket match the heads leave that to the Chevy guys that don't know any better, if you do anything check the head/intake ports for misalignment in their as-assembled position and grind where necessary to make them match better. It's pretty much a certainty that the port openings in the heads will be larger than the exits in the intake and you will have to open up and align these and not touch the heads at all.

 

LOL sorry to but into someone else's thread but i'm in need of a little head advice and you guys seem to know what your talking about, i was curious on what models and years ford produced the gt-40 head and could they be used on a carb'd 351w and if not what would work well with an Edelbrock "street master" manifold with a 780 Holley??????????? thanks

 

You're not going to see a one point change in the comp ratio from a 4 cc reduction in the chamber size on a 351. More like 3 tenths difference.

 

D6 heads would have 69-70cc chambers while some GT40s would be about 60cc.

 

Someone posted some reference to E7's ? That's where I got the 4 cc's difference.

 

lol, agreed. port-matching is the proper technique and yes, the intake ports on the head are almost always larger in diameter than the ports on the intake, unless it's a high performance intake designed for a head with larger than stock intake runners, in which case if there the port on the intake was larger than the port on the head and it presented a significant restriction to airflow then we would port match usually using the correct intake gasket, cheers

 

. Might check the price of the World Windsor Sr. iron heads...

http://www.summitracing.com/parts/wrl-053040/overview

http://www.competitionproducts.com/S.../#.U8kFaDbD-Uk (ask if can get for SBF)