Thread: 327 Build Cam Selection

Tweet

With 10.3:1 compression ratio, you will want to be careful about your dynamic compression ratio so you don't have a problem with detonation on pump gas. Use one of the DCR calculators like Wallace Racing: Dynamic Compression Ratio Calculator to plug in specs. Intake valve closing at ATDC is critical. For instance, my 383 has 10.6:1 static compression, and I originally was thinking about running a particular CompCam XE-274 but with its ATDC at 64 degrees, it put my DCR over 8.5 which is a no-no with pump gas. So I chose their Magnum 280 which had similar specs. It has a ATDC at 66 degrees which gave me a DCR of 8.46 which is acceptable for aluminum heads and 92 octane. I hope this helps.

Originally Posted by rumrumm

With 10.3:1 compression ratio, you will want to be careful about your dynamic compression ratio so you don't have a problem with detonation on pump gas. Use one of the DCR calculators like Wallace Racing: Dynamic Compression Ratio Calculator to plug in specs. Intake valve closing at ATDC is critical. For instance, my 383 has 10.6:1 static compression, and I originally was thinking about running a particular CompCam XE-274 but with its ATDC at 64 degrees, it put my DCR over 8.5 which is a no-no with pump gas. So I chose their Magnum 280 which had similar specs. It has a ATDC at 66 degrees which gave me a DCR of 8.46 which is acceptable for aluminum heads and 92 octane. I hope this helps.

Absolutely will do. the 278 cam on 110 makes very close to 8.5 DCR on my application