Quote:
Originally Posted by oldman
The Olds head is like the 1968 up 440 Dodge head, it has an open combustion chamber:
https://www.cartechbooks.com/techtip...cylinderheads/
30 to 40 years ago Hughes made a piston specific to the 440 that would take away all the quench and squeeze the charge into a small area. These were odd shaped positive deck pistons and had to be clay-ed to each piston chamber. It allowed me to run 10.5 pistons on pump gas across the HUGE 440 piston. Any modern chamber is basically a heart shaped head and a positive deck piston so ally action happens in the heart at TDC (no quench). Looking at the Olds head you are stuck with large chamber (unless somebody makes a specific piston for it). Probably going to have to drop 1 point or 1.5 points to run 92 octane. 5% loss in power for each point (you got plenty). What is your CR right now? My 2nd build on my 440 I had 11:0 forged and that was good till the early 80s, that when I went with the Hughes piston which worked till I sold the car a few years ago. If I did not do a Hughes piston I would have done 10.0 or 9.5, that is just the reality of the chamber design and the large bore. |
That is why for many years I had piles of 67 915 heads setting in my shop .. Then came the edelbrock heads and I said bye bye to my piles of 915s ..