Vacuum Secondary Conversion

That’s ok. I went to Hughes and found it. Usually I can’t find anything on that site but I did find it.

I’ve already said when I put my junk back together I’ll make some videos to cover it.

It will be 12:1 or a bit more. Who knows? When I build the W2 headed engine I may try for 12.75:1 just for fun.

And really, cam timing doesn’t play into how much compression you can run. At least within reason. 11:1 is so easy to do (if you can find pistons any more) I can’t believe guys still struggle with it.

And you’re right. Not many iron heads left out there (THANK GOD for that!!) but the W2 is still the best inline valve, 18 degree, standard port head out there. There’s not a 23 degree Chevy head (in iron) that would touch it.

And even if you never build another iron headed engine, do you really think that if I switched to an aluminum head I could be at 13.1 plus on pump gas? No chance.

I’m thinking the limit of pump fuel is 12:1 or a bit more, regardless of cam timing or any thing else.

As to cam timing, it makes little difference in how much compression you can run, except we both know more compression allows you to run more cam timing IF you need it.

The two biggest factors in using higher than orthodox compression ratios are the cooling system and the timing curve.
I should say never say never.
Funny thing, I am currently porting a set of cast iron 302 heads now, although more for the experience than any planned project. I was inspired by the postings and pictures of MoparOfficial herr, and watching all the Charlie S videos online, that I wanted to give it a try. Not sure if I will ever use them.