Ive got a 1975 Chev pickup camper special that has a 454 ,TH-400 trans and a 373 rear end. Ive owned this truck for the past 35 years and is as original as can be. I decided to give the old engine an up grade with an new carb, intake, cam, headers in the effort to improve its stock 230 HP and 450 tork. So I started with a compression test to determine health, all 8 cylinders came up with 85 PSI. This seemed to me a bit low so I checked the calibration of my tester with my air compressor and its reads correctly. So, I did a wet test and it only increased by 3 PSI. So, Im thinking that 85 PSI is normal for a 8-1 compression 1975 chev engine.. Any experience out there that confirms my results as being normal ? My truck runs great, 20 year old spark plugs show no signs of oil fowling, there has been no oil consumption in the past 20 years. Yes, today I did its first oil change in 20 years.. I only drive it twice a year to go to Lowes to get wood or something...But, all of a sudden I feel the need to build something and this old truck is what I have.. So is this compression pressure correct for this old truck ?