72 HO intake crossover
 

Can you use the reproduction 71 intake crossover and heat shield on a 72? I have the 7F6 heads for a 455 HO. The reproduction crossover is only listed to 71? It appears the 72 was different but not sure where. I have an original HO intake but not the crossover. I found an original crossover on ebay for 1500, but would like to just use the reproduction part. Comments welcome.

NO. The repro crossover won't work right on 1972 7F6 heads.
 

The 1972 crossover is not reproduced.

A 1971 exhaust crossover won't work correctly on 7F6 heads, or on any other 1972-up heads. You'll have a huge exhaust leak unless you block the exhaust ports of use some type of adaptor/shield.

The main difference is that on the 1972 crossover, both of the exhaust crossover ports are smaller.

The 1969-71 crossover is small on one side and large on the other. The heads have enough meat around the crossover ports that the gaskets will seal.

The 1972-up heads have a 2nd opening above the exhaust crossovers that doesn't normally need to be sealed. If you use the early crossover on later heads the gasket is not able to seal both openings.

This can help some:

Thank you for the comments. If you shim the upper opening and use the early gasket will it still leak? I guess another solution is to find a 72 cast iron intake or an aftermarket manifold and use it. I did find a 72 HO manifold and crossover locally for 1400, maybe I should bite the bullet and buy both and sell the one I have. Any other solutions?

Here's the complete Jim Hand explanation for the pic Kenth posted:
(bottom of the page)


Intake Comparison


:)