I bought a rod with a 454 Chev engine a couple of years ago. Engine runs fine with the exception of a very rough idle and some oil use at sustained highway RPMs. The car was built in the last 10 years and the top of the engine is all dressed up. I coded the engine and its a 73 SS model block with oval port heads. The bottom of the engine, pan and skirts are encrusted with crud and look like they have been in place for 40 years. It carries 20 LB of oil pressure at hot idle and is running fine on 89 octane.
Hopefully the rough idle is a mild cam. Seems likely with a edelbrock intake and replaced water pump. Sounds funny but its running stock exaust manifolds and very small straight through mufflers.
Given the above, and I'm a novice, how can I determine the overall engine health? Assuming a mild cam, both vacuum and compression checks would be low? Is this a correct assumption?
While doing a compression check I'll look for uneven readings and try some oil in the low ones to determine if its valves or rings. The oil use isn't a lot --I just noticed it --first time out on the highway.
Any other thoughts appreciated. Thanks