Help with 340 compression + cam change

If you're gettin 160 PSI, that's a decent combo as is. I say leave it alone. What's going to happen is, you're going to go "bigger" and lower cylinder pressure and lose power. Or you're going to go "smaller" and risk detonation on pump gas.

I use quotation marks because bigger and smaller are not good words to use regarding camshafts. What you are looking for regarding cylinder pressure are several things. Perhaps the most important is when that intake valve closes. If one cam closes the intake valve earlier than another, it will probably build more cylinder pressure. A cam that closes the intake valve later, may make less cylinder pressure.

I use "probably" and "may" because the reverse could also be true. It's all dependent on the rest of the valve events and how the camshaft is ground. Duration @ .050", lobe separation and so on.

Plus, all the formulas and online calculators in the world are really useless as tits on a boarhog, because they know nothing of real world performance. You need experience and know how with camshafts to choose wisely......and to me......it sounds like someone did that.

I agree that engine probably has a static compression ratio of "around" 8.5. So, if that thing really has 160 PSI, it's pretty snappy like it is. Ultimately, IMO, to improve upon it you will have to change the whole combo. In other words, more compression, more cam and so on.

I think you are fine right where you are with THAT particular combo.

Again, just my opinion.