carb tunning

Help me figure this out PLEASE, 3 weeks ago my car was deadly, ran 5.49 every pass unless I had the other car covered and lifted. But the motor was loading up, plugs getting black even flooded in 2nd round. Went 6 rounds and won race even with this problem. By the next week I fixed the trouble a bad power valve, but the car is no where near consistance. I thought fixing the carb would make things better not worse. Any thoughts?

Anybody have any ideals beside putting the old power valve back in and a set of new plugs every week?

Was the new PV the same number as the old one?

Yes Sir

So that says the car likes the extra fuel the power valve supplies when its open (or blown out) but it loads up when you're not in it and fouls your plugs. And it says that adding a working pv hurts your consistency some.

I'd block the pv and mess with carb jetting. Blocking the pv typically means jetting up 6-8 sizes. That should put you back to running consistant but fouling plugs. So the tune is suspect. At that point I'd try splitting the total jetting to favor the secondaries heavier and see if you can find a happy medium. I must say I prefer to run no pv's on a drag car and squared jetting if possible.

Thank you sir that is what I'm going to try this weekend at US43

We have been running a 545 BBF in a dedicated drag car here in Aust and found that deleting the power valves and upping the jetting 10 jet sizes in a squared setup was a good start point, then fine tune from there. We are running twin 950HPs with 90 jets all round. Will probably come down by a 2 or 3 sizes but our MPH is good so we are close.

We also run the carbs east-west rather than north-south - helps stp the secondaries leaning out under hard acceleration.

That what I did this weekend, but only went up 6 jets. Car varied 8 numbers but 60 fts were off 6 numbers. This is a hard tail dragster 60 fts off 6 tells you how slick the track was.