WHAT TYPE/SIZE CARB DO YOU USE?

how much fuel pressure do you have at 5000?
do you have a gauge were you can see it ,the pressure?

do you have jet extensions installed? if not, give them a try, could be a cheap fix.

It is a Pro Systems 1000cfm 4150 carb, I cleaned the filter before the first race, it is an Aeromotive reusable filter. Unfortunately I dont have a fuel pressure gauge in the car just under the hood. I do have jet extensions in it. I am going to the track next weekend again with it. I got a new filter element that I am going to try, and I am going to swap out the -6 line to -8 from regulator to carb and if that doesnt work I have another fuel pump that I will try. After thinking about it I did have the headers off several times since the dyno and in the past that has cracked the porcealin on the plug from the weight of the header on them. So I am going to try some new plugs too. I appreciate everyone's input, Thanks guys

Welll I found a couple of cracked plugs that I changed and the motor revs clean now, BUT it just leaves really soft. My 60ft times ar .05-.07 slower with my 434 than they were with my 408 that made 100hp and 45ft/lbs less. I think the converter is bad, I have another one and I will swap it and hope it fixes it. Last race my et and mph kept falling off each pass, motor felt great and sounded great, I think it has got to be converter. Any other ideas??

If my car was falling off each pass like that I would definitly check the oil filter and make sure there was nothing bad going on inside. Glad you posted back to let us know what you found. If you don't find anything bad in the filter I would change the convertor then search if that doesn't fix it.

Curtis

New converter is in, stalls at 5500. Headed to the track on Friday so hopefully it is fixed, if not I am out of ideas.

Give us an update when you make some runs.

Curtis

IT'S FIXED! My best pass was a 6.59 with a 1.42 60 ft time on a marginal track at best. That was at around 7800 feet too. I think with decent traction it will settle in the mid 6.50's. Thanks everybody for all of your help. I never would have even thought converter had it not been brought up on here. Thanks a ton!

Glad to hear you found the problem. Now you can concentrate on racing.

Curtis