Cam help

Will_H#24 said
How would I know if it's a 10-1 engine. It's original to the car with just over 51,000 miles on it.

68~71 340's were spec'd out with 10.5:1 compression

but a lot can happen in 50 years.... i'd get a cranking compression test and see how much PSI you're bumping and that should get you in the ball park.

unless you have a detailed build sheet with the specifics listed then you're just making a somewhat educated guess off the cranking compression psi.