Distributor calibrating

[David N.]

I am in the process of rebuilding our '69 BB 427 and after reading a couple of the recent postings it suggested a question.

I am using the suggestions as follows: Lower compression ratio=8.8, mild cam, and some other modifications.

My question is, do you recommend re-calibration of the distributor advance curve? And if yes, any recommendations as to where in the metropolitan Detroit, MI area?

[Timothy B.]

Re: Distributor calibrating

David,
If you are rebuilding your 427 and installing a camshaft different than stock you may want to pay closer attention to the compression ratio. If the intake valve timing (point which the intake closes) is later then the stock cam the lower compression pistons are the wrong way to go. Stick with stock compression or check out slightly higher compression pistons.

Generally with a high performance camshaft the advance curve can be quickened to ignite the slow burning diluted air/gas mixture. Then there is the vacuum advance diaphram which needs to be properly matched to the new engine vacuum readings. If you stick with the stock parts GM has allready engineered the engine for you.

[Duke W.]

Re: Distributor calibrating

I am using the suggestions as follows: Lower compression ratio=8.8, mild cam, and some other modifications.

You found these suggestions on this forum? Maybe you are confusing it with another forum.

What OE engine do you have?

What's a "mild cam"?

What "other modifications"?

Duke