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slocobra
07-04-2007, 09:09 PM
I just posted a project thread for my Falcon, but I thought maybe you guys could help me with my chevelle since I am pretty much a die hard Ford guy........:help:

I have a 70 chevelle I bought from a friend a few months ago and have been cleaning it up and kind of turning it back into a street car.

Here is my problem. I don't know where to really start on the timing and tuning on it. SBF is obvisouly way different.

Here is the combo on the motor:
400 smallblock
pretty heavily ported sportsman II heads
isky z-75 (570 lift and 274@50 on a 108)
11:1
victor JR
850 DP
MSD ignition

I took it to the track and it ran ok but not great. It seems I have a timing problem, and I got to thinking maybe I am way off on what initial and total should be on a chevy like this.

It also is way rich at idle and every now and then it pops throught the exhaust (jsut started doing that) after its warm.

I know the primary jetting is/was 78 and it didn't have any effect dialing in the idle air mixture screws. I jetted it to 71 and its way better at idle and the screws seem to function again. It was so rich at idle with the 78's my wideband was pegged with the screws all the way in.

The PV is good, I checked it.


any help or suggestions would be appreciated. I am not really into chevys that much but love 68-72 chevelles. oh and I guess 70 camaros since I have that one other chevy...don't tell my ford friends:secret:

Johnny Blaze
07-07-2007, 04:28 AM
What is your initial timing? Total?

As for carb settings, did you adjust the mixture screws by ear? Or with a vacum gauge?

slocobra
07-07-2007, 08:02 PM
Well by ear to see if it was even making any difference, then just put them to the factory setting. I think total was like 34ish