Need help from some pros
 

Although I'm just a bracket racer I thought maybe some of you professionals could help me out. All of a sudden my car has slowed down. 2 weeks ago I was going consistent 8.18's,8.19's in the eighth mile. Last week car started going 8.40's, 8.39's with almost 3 mph loss also. So I thought , maybe the track, air, etc. you know the deal. Last night car went the same 8.45,8.42,8.39, still down on mph also.
First round I dialed 8.38 figureing I could just run it out and still be good with no worry. Well I broke out with a 8.372. Is this car telling me that it's too rich and wants to run faster as the night gets cooler?
If I advance the timing 2 degrees will this lean it out a little and tell me if that's the case, or do you think something else is going on here? It's a 454 motor with the timing set at 35 degrees right now.
Any help is greatly appreciated. I'm beside myself with this problem. Thanks-Russ

Re: Need help from some pros
 

Have you checked the valves lately? Compression Test?

Re: Need help from some pros
 

Russ,
Check your PM's ;~)

Re: Need help from some pros
 

Do a quick check to see if the carb is opening all the way up. been their do that! Oh also check timing to make sure it hasn't slipped. I picked the old 4-door nova up .5 @ Indy Div. last year! Yes .5 not .05 !

Re: Need help from some pros
 

Like I told Adger, I have about 150 runs on the springs, with the timing at 35-36 degrees and shifting at 5500rpm

Re: Need help from some pros
 

what type of rear end housing is in the car? If it was originally designed for a V-6, there is a chance that the big block torque has slightly bent the ends of the housing forward. That will easily scrub off 2 tenths of ET. How are the rear tires wearing?

Re: Need help from some pros
 

Well I guess easy things first. Greg , I'll check to see if the carb is opening completely, then put a timing light on it to see if the vac. advance is working properly and see if the timing skipped. Then check the valve lash. It's a Comp Hyd. .540 lift, so it will be easy to see if any have loosened up I guess. thanks to all you guys giving me suggestions.
If I know what the converter flashed too 2 years ago, will it tell me anything if I flash it and see it flashing a lot lower or higher this time? Thanks again to all. Russ

Re: Need help from some pros
 

I would say if it doesn't flash as high, it might not be making torque like it used to.
When was the last time you had the transmission freshened up?

Re: Need help from some pros
 

You stated that you thought it might be the weather and it very well could be. what was the DA for each run, if you are 2/10 off in the same air conditions you most likely have something going on. But if the 8.18 is at lets say 1000da and the 8.39 is at 3000da you could be ok the engine is just giving up .01 for every 100 feet or so in density altitude. just my .02 but more info would be needed to say if the weather or something else is to blame.

Re: Need help from some pros
 

As Rob said, more might need to be checked if it isn't DA causing your lost ET & MPH.
SO: after re reading your posts....
Get rid of the Vac advance. Race cars don't need it. Vac advance is only on cars for gas mileage at cruise speed. I've never seen a race car that cruises or needs part throttle gas mileage. :~) Check the mech. advance & make sure it is only going to a total of 36-38 to start with or use your old tune up setting. Then check the valve setting. Then check the spring pressure. Run a compression test on all cylinders after the valve setting or run a leak down instead of compression test... Leak down test is best. If it stalls less you are down on power. Carb linkage slip is a good thought too....Hope this helps you find the lost power.