In 1970, the 455 had 10 to 1 compression. In later years, Buick dorpped the compression. How did they achieve this? Did they change the piston height or the heads, or both. If you had a 72-75 455 that was set up exactly as it was munufactured, would bolting on TA's stage 2 heads give that motor approx. 10 to 1 compression? Would you have to change the pistons with the stage 2 heads to get a high compression? Thanks
according to this page, there's also a variation in piston dishing. the head cc change from 74 to 75 is probably how they got down to 7.9 http://www.taperformance.com/newpage1.htm Piston is a lightweight aluminum casting, with a minor dish for 10:1 compression ratio engines, and a fairly deep dish for 8.5:1 and 7.9:1 engines.
