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Discussion Starter #1
I have a 1966 Chevelle big tire car weighs 3000 lbs. on a chassis dyno max tq 612 at 5700 hp 817 at 8000 but it should have gone to an even more rpm but the gains weren’t that much.

I have the following to work with:
Trans: TH 400 or Powerglide
Gears: 514 or 567 or any other set up
Converter: started with a 6700 then I tried a 6200 in the car now and I have a 5600 converter all built by Chance
Tires: Hoosier 32/14.5/15

Fastest so far was a 5.62 at 124.8 mph with a 1.27 60 ft.
Class I’m trying to run is a 5.50 class in the 1/8 th.

Recommendations on combination please.
 

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So you’re turning the same ET but 4mph faster after engine mods? It seems you were looking at the same trans changes last year around June.

what low gear in the glide?

Low gear in the T400?

Was it a “happy” chassis dyno?

Viperguy mentioned the target stall, that rpm works compared to the 3 stalls u mentioned.

With everything perfect and all stars aligned, you’re looking at maybe a 5.38 and 1.17ish 60’ with a 1.64 glide and 5.14s. YMMV
 

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I have a 1966 Chevelle big tire car weighs 3000 lbs. on a chassis dyno max tq 612 at 5700 hp 817 at 8000 but it should have gone to an even more rpm but the gains weren’t that much.

I have the following to work with:
Trans: TH 400 or Powerglide
Gears: 514 or 567 or any other set up
Converter: started with a 6700 then I tried a 6200 in the car now and I have a 5600 converter all built by Chance
Tires: Hoosier 32/14.5/15

Fastest so far was a 5.62 at 124.8 mph with a 1.27 60 ft.
Class I’m trying to run is a 5.50 class in the 1/8 th.

Recommendations on combination please.
If you make peak power at 8000 rpm you need around a 7000 flash speed, there is no way around it. You can get by with slightly less but it will most likely slow down.
 

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Discussion Starter #5 (Edited)
The glide has a 1.80 cut straight first gear. The TH 400 has a 2.46 first gear. I currently have the Powerglide and the 5.14 gears. With the glide I have an aluminum drive safe. I had the 5.67 gears in the rear with the glide but my mph dropped to 119. I would expect the mph to go down. The estimated HP was at least 940 estimated but Eric Weingartner. The first dyno I was on it had the 6700 converter and he stated that I didn’t have enough rpms between stall and 8000 and that the converter needed to be much closer to my max TQ which was at 5700. At a different dyno with the 6200 converter and the 5.67 gears was the last dyno. I didn’t go back to the TH 400 because of the weight difference. Would the 2.46 gear and the TH 400 work better then the glide 1.80 first gear and the 5.67 gear?

Thanks for the replies.
 

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You might get by with power adder stuff with converter fall back near torque area.We have had good luck with 2.10 low in 3 speed and rear gear that keeps our rpm at peak hp at finish line.So if you make peak hp at 8000 you should shift like 4-500 rpm higher than that and be at least 8000 at finish line if not a little above.This means your fall back area is 900 rpm below peak and converter designed to not have high slippage at finish line also.Normally lower rear gear helps tighten converter some.imo you would need a real light car and big cubic inch to lug motor down to torque peak and get decent et.If that is plan better gear the wee out of it.Im guessing also 5.38 to 5.67 prob wont see much diff in et or speed so I wouldn't keep spending money there.Converter or clutch is real key to quick et etc.
 

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Discussion Starter #10
Thank you for the offer Vegaman924. I have a Dana S60.
Rick. The Chevelle weighs 2700 without me in the car. Maybe a little less with only one battery. I have fiberglass front clip, doors, trunk lid and all Lexan windows. The car is back halved. I could loose some weight in the floor but little left after the back half and firewall moved back and lighten. I have an aluminum drive shaft and Powerglide trans. I even use a very small radiator. The chassis is stock from the back half forward. So I think chassis and boxes on either side of the firewall is all I can lightened. I thought about going to a smaller tire to make it a small tire car but it barely holds now with a 32/14.5/15 tire. It’s a ladder bar car.

Thanks again.
 

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BTD has it. What shows the most power on a chassis dyno is most likely not going to be the fastest on the track. The chassis dyno will generally load the converter more than the track.

I would sell a few converters and gears and pull the engine out of the car and put it on an engine dyno. Then no more guessing required.

Jason G.
 

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Or put a Go-Pro on your tach during a pass. Cheap datalogger if you don't have one. That will tell you what is going on .

Jason G.
 

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Just an observation, there has been plenty of focus on: motor (HP & TQ), trans/converters, gearing & big tire!

What about the fundamentals of suspension. The only known is "ladder bar car". I would be concerning myself with shocks, springs, travel, etc. both front & back. IMO, that's where the focus should start, before anything else! ;)
 

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Discussion Starter #16
Thank you for the replies. I do use a Go Pro to log my AFR. Next time out I will record the tack.
I have double adjustable shocks front and back with new springs. Chevelle Mike said on launch I was getting on top of my rear tires. Don’t know what was meant by that or how to correct it. No engine dyno was done. Mistake on my part. I have video of my 5.62 at 123 mph, but the 330 was only 3.63 and I know it has to be a lot closer to 3.50 at the 330.
 

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This may not be what you wanna hear, but to just pick up a tenth if the class will allow it throw a small plate on it and tune to where you need. It wouldn’t take much at all. Maybe even back the motor off a tad and put 100 pull in it. To run 5.50 you really need to run a little faster anyway. Just a thought
 

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Discussion Starter #18
I have thought about nitrous but it’s dual carbs and out of my range of even possible expertise. It’s kinda high compression ratio is also a concern at 15.9.
 

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Send your manifold to induction solutions and have him put plenum bar in it.That compression will work with small amount of nitrous to gain what you need.Gliddens and mopar guys did it in pro stock.Their engines more on the edge than yours.Steve get you a tune that would work.Gonna be hard to pick up na without allot of money spent
 

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Just an observation, there has been plenty of focus on: motor (HP & TQ), trans/converters, gearing & big tire!

What about the fundamentals of suspension. The only known is "ladder bar car". I would be concerning myself with shocks, springs, travel, etc. both front & back. IMO, that's where the focus should start, before anything else! ;)
I'm going to be blunt, post up the darn video! We don't care what you think your 330' should have been. I'm not an expert at suspension tuning, but I know if I want to improve the 60'. That's where I would start when the rest of the combo is in the ball park. If the video is taken at the right angle, it will tell a lot of the story. I'm sure members can help with evaluating your suspension.

There has been a majority of post dealing with your motor, trans/converter, gearing & big tire; only 1 post with 1 like. My posts alone has 3 likes, not saying we are right. Again, that's where you might start! ;)

I wish you the best of luck with your set-up & someone else said it 1st. In order to run a 5.50 Index competitively, you need to be quicker than the index.
 
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