quote:Originally posted by DAVID KAHN:
I wish to purcase complete aluminum heads and the ad says 2v intake and 4v ports. Is this correct for the pantera?
Only one aftermarket (aluminum) cylinder head has full size 4V ports ... the CHI 4V cylinder head. The intake ports of the CHI 3V heads, the high port AFD heads and the Scott Cook heads are all actually stuffed 4V ports. The ports are a bit narrower and the floors of the ports are filled so the ports are less tall. CHI also cheats a bit and raises the ports higher than the stock 4V height.
The closest thing to a 4V size intake port amongst the racing heads sold by Ford was the intake port of the SVO M-6049-A3 cylinder head, which was a stuffed 4V port that was also raised. As Doug mentioned, since the CHI 3V intake port is also slightly raised, it aligns relatively well with the intake port of the SVO "A3" cylinder head.
Several 2V intake manifolds have extra "flange" material around the mounting flange allowing them to seal up against the larger intake port of the 4V cylinder head. The Edelbrock RPM Air Gap is one such manifold.
Notice however, that the floor of a stuffed 4V port is filled-in, where as a 2V manifold aligns with the floor of a 4V intake port. This would create quite a mis-match and would require some grinding to align things. Unless of course the alloy head in question is the CHI 4V cylinder head.
So the question remains which heads and which intake manifold are being referred to?
I'd like to mention that Scott Cook sells a dual plane manifold designed for stuffed 4V ports, its a well engineered manifold. His stuffed 4V cylinder heads, designed by Darin Morgan of Rehr Morrison Racing Engines, are the best of the standard 4V port height aluminum cylinder heads. The heads and manifold combined constitute a thoroughly modern and powerful induction system. Its hard to beat the performance of an iron 4V cylinder head, yet the Scott Cook induction system offers the potential of an additional 70 bolt-on horsepower with no other changes to the motor.
If a single plane manifold is more to your liking, two Australian based manufacturers, Terry Parker and TFC, sell high rise single plane manifolds designed specifically for stuffed 4V ports.
-G
