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Trans gear combo suggestion?

PostPosted: Tue Jan 07, 2014 2:56 pm
by badhabit406
Well the rear engine dragster we were working on ended up junk and we said screw it and built a new chassis. Only instead of a rear engine dragster its a two seat all tube pro mod chassis. And in place of the big block ive got a 5.3 LS with some nitrous should be 550-600 hp @ 6700rpm and total wieght 2000lbs. Ive got a glide and th400 here and have been working different calculators and banging my head on what to use and what ring and pinion. Please help!

Re: Trans gear combo suggestion?

PostPosted: Wed Jan 08, 2014 5:20 am
by THE BOSS
no expert here but most use a 6:00-6:50 gear range with a glide

I had a BBC NOS rear engine dragster for a year, used a TH400 because I had it, it had a 3:90 gear and I just used first and second gear only. it ran 3.60 every pass.
at the end of the year I put a 4:88 gear in it to see what would happen if I used all 3 gears, it went way slower.

hope this helps.

Re: Trans gear combo suggestion?

PostPosted: Wed Jan 08, 2014 11:52 am
by badhabit406
Everything helps thanks bob. My original plan was to use the 6.50 and glide in the dragster but with more wieght and less power got me to second guess myself. Seems like most of the simular powered jeeps use 6ish gear with glide but also use low range just worried with this little motor she will release the button and it will die :lol:

Re: Trans gear combo suggestion?

PostPosted: Wed Jan 08, 2014 1:40 pm
by sandaltered
I had 7.00 gear and 1.76 glide in my Jeep with two different SBCs. One was ~ 550 hp, the other 660. It seemed to do OK for bracket racing. If I really wanted it perfect, I probably would've went with more gear if I could. At about 2400 lbs the smaller motor went 4.45 and I think the bigger went 4.20. I never really got much time to tinker with either of them very much. Only ran the Jeep a handful of times.

Re: Trans gear combo suggestion?

PostPosted: Wed Jan 08, 2014 7:02 pm
by scoutracer
Hi, I run a 6.83 gear, weight is similar, same power range with a n.a. 377. It has run a best of 3.93 @ 83 mph, at 7,000 rpm in the lights. It's a 2 w.d. 125 inch wheel base single seater. best 60 foot 1.46. with a 1.76 glide. Good luck!

Re: Trans gear combo suggestion?

PostPosted: Fri Feb 06, 2015 11:39 pm
by Straight Shooter
No higher than 6.50. 6.50 to 7.33 will be just fine. Ideally a final drive of about 9-1 is what my 2300 pound Jeep used with a manual transmission and the same power your 5.3 is predicted. When I switched to a 1.76 glide I had the 6.17's in it with a 6000 stall and it ran 4.23. It was way too high geared and just laid on the converter in high. A 7.17 would have really woke it up along with a looser converter. It went over the wall before we ever got to try anything with it. Now the engine is in a 1600 pound rear engine buggy and it runs 3.5's to 3.7's with 1.76 glide, 7300 stall, 7.00 gears. It runs the same with 6.20 through 7.00. If they would hold up I want to try 7.33 or lower. I have a buddy with a quick change rear in his rear engine car and he runs an 11-1 final drive in high.

The lighter 5.3 will act the same as a big block with 200 to 250 more horse power. Weight on sand is super critical.