2+2GT

With an upgrade cam, even a mild one, the 600 is probably the better choice.

Even crappy Ford iron heads can benefit a lot from some home port-matching on the exhaust side. Always a weakness of 289 and 302 heads.

That aluminum intake was the last version of the 60's iron 4V, not the greatest but it didn't totally suck, it was used on the 289HP. There was an early manifold that predated that, a repro is still available.

my77stang

nope, thats not the same intake. the early 80's intakes ford used had a "waffle" looking pattern all over them and the intake runners were literally almost the size of a 255 intake port. here's a pic of 1 i found on fleabay just so you can see what im talking about.



the heads i had on that motor were not ported at all, and like i said they were the E6SE heads which had the heart shaped chambers and were literally the worst flowing heads ever bolted to a 302 from ford.

couple the above known facts with a stock single exhaust system and that carb still worked perfectly. the cam was a 218/228 .471/.471 summit grind and was the only thing done to the motor.

2+2GT

True, it was not the same part, but it was the same design. Flip one of the photos and you'll see the runner design was virtually identical. I have seen these side by side, and it's pretty plain the manifold you have is the last version of the one I posted, which was the first. I agree, your heads are the pits. It'll take a lot of porting, at least on the exhaust side, to get them up to par. If you can do this yourself, it won't cost much, just the cost of a "valve job" gasket set.

The exhaust ports of the 289/302 head were always poor, and every time they changed the emissions setup they got worse. Odd, when you consider the 351W head was excellent, later on was adapted to the 5.0 HO and called the "GT40" head.

Crane used to sell "Fireball" heads, they would buy 289HP (later, 302) heads from Ford, and port the exhaust massively. You have to see the size of the hole to believe it:

my77stang

runner design may have been the same, but the actual size of the ports were friggen TINY - much smaller than the heads themselves.

also, the motor i spoke of has long since been out of the car. im sporting a balanced 289 rotating assembly stuffed in a zero decked roller 5.0 block with 69 351w heads that have a whole lotta machine work done to them

flyingfool

from the factory, ford was offering the autolite 4100s. 480cfm and 600csf (second number not positive about) so that right there is a reference. some people say that they cant actually perform to their rated cfm however