ZL-1 block versus Can-Am block?

[RALLY]

Originally Posted by Sean

I used to talk to Bill on a regular basis before he passed. I know he did not like the aluminum blocks at all. Even the cylinder heads. Those blocks have a lot of porosity in them just not compact enough. On the dyno your looking at a 10-12% loss

Agree, Bill said the Aluminum heads didnt put out the horsepower like the iron head then. Thinking heat transfer had something to do with it. Yes the aluminum heads were lighter, but loss of horsepower was down.