Compression Ratios

krcilek

What is a suitable compression ratio for the 401 with standard bore and edlebrock 54cc heads. This will be for cruising and highway driving and perhaps very light towing. Want to use pump gas only. Is 10:1 good? what is the effect on a different ratio like 8.5:1 etc?

tufcj

You might get away with 10:1 with premium gas and aluminum heads. They dissipate heat a little quicker, so the compression can be a little higher than iron heads. You'll probably have a ping if you tow. I'd keep the compression in the 9-9.5:1 range for a street engine. My AMX is running 10.1:1 compression with ported/polished iron heads. Running premium gas, I can detect a slight ping when I romp on the throttle. Bob tufcj