The 455 engine i put in my 71' skylark is a combination of 73' and 75' engines. The 73' block sonic tested one cylinder at 99 thousandths. So i used the thicker walled 75 block (great sonic test) and the 73' heads. I did not measure the heads to find out what cc they were so i'm kinda lost on how to figure the compression ratio. Stock 73' heads, 6.1 Ta roller rockers, Ta 310 cam. Single plane Ta intake. Bored 40 over but i don't remember the info on the Ta pistons i used. I spoke with Mike at time i ordered parts (approx 4 yrs ago, when i was assembling the engine) and used the setup he stated his dad had in his GS at the time. So any ball park est would be greatly appreciated. Thank you.
