[Jack Zupan]

"Drag racers in the know would use 4V closed chamber heads, a 351W block,
and one of the Ford Motosport high port intakes which were available for
both 9.2" and 9.5" deck blocks and would bolt up to the 4V heads. 4V heads
with a bit of clean up work flow 300 CFM. That combo still works today."

This may not be such a great combo on the street. I still have a set of closed chamber 4V heads but never put them on because the people I knew that had used them all complained about the lack of low end torque. Once the rpm's were up they would go like crazy however.

"The aluminum Ford Motorsport blocks are in the same price range as
the Fontana. Both the Fontana and Siamese bore Motorsport blocks will
go out to 454+ cubes. Comparing an aluminum race block to an iron race
block on cost isn't exactly fair but if you don't mind the weight penalty,
the iron race blocks are less expensive. Note that the iron race blocks
come in at 205 lbs (per the Ford Motorsport catalog). My Fontana weighed
in at 116 lbs. That's quite a bit of difference. Aluminum blocks can
also be easily repaird if damaged."

Actually I was thinking street car when I replied. I wouldn't but an aluminum racing block in a Cobra unless I was doing a lot of racing. In this case a weight penalty with a small block in a 2600 lb Cobra is really a non-issue.

Jack Z.