I was talking to a local hot rod guy the other day about my bogging problems... When I first touch the gas the vacuum drops to about 6Hg (I have a gauge in the car).

I set my base timing on my 350 at 6*BTDC. I also notice when it's hot the starter has trouble turning it over.

He told me with increased compression, and a hairier cam, the base timing is going to change from stock..

Well, could someone elaborate more on this for me?

I'm at 9.5 - 10:1 compression (Flat tops and 64CC heads), my cam is a Lunati 60101 (lift and timing in my sig).

 

I'm by far no expert on this stuff, but that cam is close enough to stock that I would think a stock timing curve should work ok.

 

Base timing really depends on the camshaft duration. The more duration a cam has, the higher the base timing needs to be. There is a drawback to increasing the base timing. An engine also likes a specific total timing.

Lets say you have a base timing of 6* and the distributor allows a maximum of 34* timing. If you bump the base timing to 12*, the total timing will increase to 40* which may be too much and you'll lose power.

You need to determine where the best base timing is and adjust the mechanical advance to limit the amount of total timing to keep it where the engine likes it the best.

A good rule of thumb to determine a good base timing starting point

6 to 8 degrees of initial timing when the camshaft duration is less than 200 degrees @ 0.050-inch of valve lift.

10 to 12 degrees of initial timing when the camshaft duration is less than 220 degrees @ 0.050-inch of valve lift.

14 to 16 degrees of initial timing when the camshaft duration is less than 240 degrees @ 0.050-inch of valve lift.

18 to 20 degrees of initial timing when the camshaft duration is less than 260 degrees @ 0.050-inch of valve lift.

22 to 24 degrees of initial timing when the camshaft duration is less than 280 degrees @ 0.050-inch of valve lift

You Lunati cam is below 220* @ 0.050 so your base timing should be in the 10-12* range.