Need Drag racers tuning help Please!

[D72CamaroZ28]

Ok, I'm helping a friend of mine with his 77 Camaro and need some help to figure out where his 60' is? What were working with is

1977 Camaro
3400 lbs.
13.5-1 383ci stroker
Luniti solid roller 642 lift 272 dur
AFR 220 aluminum heads 2.08 1.6 valves
Match ported aluminum single plane intake
1040 cfm 4150 Biggs carb built for motor
6AL with new pro billet
1 3/4" headers
TH350 manual Valve body
Continintal 5200 stall 8" converter
Nine inch ford with 4.56 gear (now)
Moroso trick springs in front
Cal tracks out back
28/10.5/15 MT slicks

Hears the story lol, He had a 800cfm Edelbrock carb and a Huges GM4500 stall converter in the car and was running 12.0 at 112mph 1.60 60' and was looking for more power like most of us. So he called up Biggs carbs and ordered a custom built carb. They told him he needed a stage five 1040cfm 4150 so thats what he got. He put it on the car and gained mph but lost ET and 60'. He called them and they told him it was due to the converter being to tight. Ok, so he ordered a new converter. This kind of stuff has kept happening to him. He had 1 1/2" headers so he got new ones. Tried changing gear everywhere from 4.10-5.14! No matter what he has done to the car it allways runs 12.0 - 12.20 with a 1.7-1.8 60'. I found it very odd that with all of these changes Nothing! has changed the ET for the better or worse. My opinon is that this car should run in the mid 11.s but just wont 60' I am pleading for some help because I'm totaly lost? Thanks in advance for the help guys!

 

[tyster]

That combo should flat out get it. I'm sure some one will have a clue. Not sure about the carb myself. If ya made that change and it slowed, i'd start there. What actual cfm is the carb. My Pros Systems XC 1000 4150 is actually 880 cfm. Also how solid is the trans?

 

[D72CamaroZ28]

The trans was rebuilt in the winter so was new this year. The carb is suposed to flow 1040cfm as per biggs carbs. I just am puzzled that changing everything but the color of the car and it still runs the same ET it did two years ago. At least if it got worse we could fix it! lol But I'm wondering about the Carb myself. Thanks for trying to help TY!

 

[1980RS]

When you oredered the carb did you tell them that you are at 5200 ft. alt.?
That is kind of funny that nothing changed. I went from a 750 demon to a 850 last week and picked up 2 thenths and 2.5 mph.

 

[BB1969]

I think you should go back to your original set up to get your baseline time back. Then do one change at a time to see which change helps et and which hurts et. As for the carb i was thinking its a little large for your application even if you gained mph thats a sign of horsepower but at the expense of low end torque thats killing your 60 ft. just my opinion.

 

[1980RS]

If that is 272° duration at .050 drop that number down to the 260° range. That's a lot of duration for that engine. Just my opinion.

 

[BB1969]

Hows your spark plugs look could it be running a little rich?

 

[D72CamaroZ28]

As far as how the plugs look there great and it doesnt run rich or stumble. I told him tonight that maybe he just doesnt have the volicity to run that big 4150 carb. I'm no engine builder so I'm just guessing here. I wish we could try a smaller carb again but we dont have one to try right now. But even with the carb problem shouldnt his ET have changed when he went to the 5.14 gear vs the 4.10?

 

[1980RS]

5200 stall convert too tight...I don't think so.

 

[fuzzy dice]

I run an old school set up as well...two things I notice...single plane intakes are more for top end versus grunt...dual planes like the hole better...also, you can only do so much with a small tire...28x10.5x15 is a small tire....

I run an 81 at 3360 lbs....very mild 461 with iron heads and a .598 lift solid flat tappet cam...APD 830 cfm carb and 10.6 CR and a single plane Dart intake...93 octane pump gas...same tire out back but with stock leaf springs, Southside Machine bars and 3 way adj. shocks...4700 stall FTI converter and a Turbo 400 tranny...nothin fancy at all...

My short times are in the 1.52-1.53 range and it runs about 11.40 at +3500 DA and 11.teens at +600 DA....

Seems like at your altitude he is OK...