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Discussion Starter · #1 ·
I have a 67 Fastback with a rebuilt engine and a 3/4 racing cam. I have a new carb and Petronix ignition. The car runs great when you give it normal gas, however, when you "romp down" on the accelerator to ?pass, etc the engine stutters and sputters, then finally kicks it and runs like a bat out of hades. It is the 4-5 seconds of sputtering that worries me. It almost feels like it is not getting enough air, like the choke isn't working. However, it does it even when the engine is hot. Do you think it is the Petronix ignition is not made for a racing cam or is it a carb problem. Any help/thoughts ideas will be greatly appreciated. Thanks, Ken

67 Fastback, 390 AT,PS,PB,AC, Deluxe interoir

6,911 Posts
your descriptions are vague; familiarize yourself with the following and post them when asking;

1. cam specs

2. brand and model of intake

3. distributor brand and mechanical advance calibration

4. if an automatic tranny, stall speed

5. rear gearing

6. carb brand, model #, and size

so I can only "shoot blind" here.....probably accelerator pump...

if the carb is a holley, there's 2 holes in the throttle arm...most pump cams (the plastic piece behind the throttle arm) shoot more fuel if the screw is in the hole marked 2....additionally, the nozzle the accelerator fuel is shot out of can be changed (carefully so it doesn't drop down the intake...that would be bad!!) and is marked in thousandths of an inch..demons are holleys and I believe the same applies.

edelbrocks have an arm at the front top that has 3 holes....putting the linkage into the back hole increases shot and you can get a bigger nozzle for it.

One of the biggest probs folks get into is using a (for example) 305 comp cam with a stock converter and 2.75 takes half an hour to get into the power band!!!

The entire driveline needs to be thought of as a package where every piece compliments the others
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