cams

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Well, I'm more used to 1/4 mile times, but it seems to lay down if it's pulling the tires 6" on the line. Have you debugged the other stuff like the fuel pressure, etc?
 
yeah i havent done much to it the carb was way to rich plugs were very black fuel pressure was 7.5 i going to put pump gas in it and try. The timim=ng is at 32
 
fouled plugs are probably from low vacuum from cam...and carb not correctly adjusted for long duration camshaft..
 
RyanUpdike70 said:
86
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RPM will tell you your horsepower. You can make adjustments to the timing or other changes and see if your mph goes up or down. With a good launch your mph and ET will move in oposite directions. I ran my 440 with a 509 (back in the day) at closer to 36 total. If you do not get detonation with pump gas I doubt race gas will benefit the car. If pump gas won't let you run 36, then the race gas should. Ultimately let the mph tell you where to run the timing.

The power valve opens an enrichment circuit. The number on the valve tells you when it is supposed to open. I have seen cars with a 10.5 power valve run like crap and foul the plugs because the cam did not pull enough vacuum to close the valve. I think the "rule of thumb" is to take your vacuum at idle and half it as a starting point. Example, if you are pulling 17 inches start with an 8.5 power valve. The old school way we used to do it was try and see if the mph changes. Now I have a wide band O2 meter and a data logger.
 
RyanUpdike70 said:
carb was way to rich
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The next step after the power valve if it is still running too rich is to start stepping down in jet size. Without a wideband you can read the plugs - but you have to be very regimented. Make a pass, cut the engine, do not idle back to the pits, pull a plug and check it. Probably better to just use mph to tell you.

Run one pass with current jet size. Drop two sizes all four corners, run again. Did the mph go up? If so, keep going. If it goes down you are going the wrong direction. If it does not change go back, or try the other direction. Check timing after any other change. Everything affects timing. Some cars can be a bit sensitive, track temperature and barometric pressure can affect the cars tune. If you are going to be serious about bracket racing you will want to start keeping track of temp, barometric pressure, oil temperature, tire pressure and anything else you would be inclined to adjust. You will learn as you go what the car likes.

By the way - nothing wrong with the 509 for your application. Without changing the heads you will not see any drastic improvement going to a different hydraulic. I say tune and milk what you have, make it run right before throwing parts at it.
 
mosleyme said:
By the way - nothing wrong with the 509 for your application. Without changing the heads you will not see any drastic improvement going to a different hydraulic. I say tune and milk what you have, make it run right before throwing parts at it.
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The whole post was really good. Thumbs up bro!
The quoted above the best part and the longest part of it all to sort out and discover.



OH! - RYAN!

What ignition are you running and what is the gap on the plugs?
 
i have been talking a little to promax pefermance out of indy about porting the heads. I run champion plugs and msd igtion

Thanks everyone for the help
 
Have you scaled the car or tuned the suspension and ladder bars?
Was the convertor bought for this combo or something else?
How do you know it's "way too rich"?
 
Start with tuning then... They shouldnt be black in a race car.
On the scaling, it's not the total, but the weight on each corner. What is your pinion angle? What kind of front mount do you have the the ladder bars? Why the counterweight?
 
That combo should run 7.2s or better with what you have, The .509 believe it or not will go 10s in an A body, i've witnessed it a few times over the years, Black plugs is not helping you, another thing is making shure that cam is degreed, PS cams have a bad tendensy of being way off, & & overlap on the .509 its very cridical its checked & advanced apon install, The .509 works "great" with fairly stock heads. Your MPH sucks for the ET, I ran the XE284H in a 451 with 9.73 compression, bone stock 906s @ 3200 lbs., 4400 PTC 9.5" & 4.10 gears, Swapmeet 750dp, M1 single & headers. This cam was a bit less then the .509, Was set-up at 105.5, I shifted at 5600 & car ran many 7.0s in the heat & mid 6.9s in the cool air with a best of 6.91 on a 1.51, MPH was 97-99. At 3300 that car should be running 7.2s @ 96-97 with ease IMO. So get to working the bugs out & leave the cam in, just degree it.

If your running basic FTs around .020" below deck & un-milled open chambered heads your not at a true 10.5.1 i ashure you.
 
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