Quote:
Posted by Unit 5302:
The 351C 4V heads are NOT the same as the Boss 302 heads. The Boss 302 heads are more aggressive than the 4V heads. The Boss 302 got bigger valves than the 4V heads in 1969 (which doesn't really matter for 1971), and they flow better.
|
The 1970 Boss 302 heads and the 1970 351C 4V are virtually identical. The biggest difference is in the water passages. The valves are the same size, the ports are the same, and both are closed chamber. The '70 351C 4V and the '69 Boss heads have the same size combustion chambers, while the '70 Boss heads chamber is slightly smaller. The differences on top weren't common until 1971. Nit picking aside, the only point I argue with Unit is which heads flowed better. The 1970 Boss heads, which were virtually identical to the 1970 351C 4V heads, were much better suited for the engine. The '70 Boss heads worked better than the '69 Boss heads.
I completely agree with Unit on everything else. As far as the bottom end is concerned, the Boss short block was completely different than the windsor 302 short block. Even the rods were different lengths.
The Boss 351 was very different from the 351C 4V as well.
Take care,
-Chris