which gear ratio for 1/8 drag strip?

-
moparmatt19

moparmatt19

Well-Known Member
Joined
Jan 13, 2014
Messages
135
Reaction score
5
Location
mosheim,tn
Ok my setup has been a barracuda race weight at 3450 lbs.
Running a 360 with 10.3-1 comp , ported 596's with 2.02's
Holley strip dominator single plane with an AED 750hp DP carb.
Hughes solid cam 248° 252° @ .050 .563 .572 lift
Ran 727 and turbo action S800 street 3500 stall and 3.91 sure grip and 30/10.5/15 slicks.
Car is running 11.99 @ 110 in the 1/4.
Car was built to run on street until now.
Engine is going into a 3,000 lb race weight or less chassis and swapping to a 904 trans with a 5000 stall converter. And possible a trans brake. I'm wanting to set it up for strictly 1/8 runs. Not sure yet but thinking on using my low gear set in the 904. Question is what gear ratio and tire size should I run for the 1/8 mile? I have a set of 5.13's I'm thinking about trying out and probably 32in slicks. But want you 1/8 racers to chime in on this.
I never ran the car enough to dial in the best shift points but it seem to run the quickest shifting at 6800 rpms. So I would like to shift in that area and go through traps at around 7k and possibly up to 7200 rpms. But NO HiGHER!
Thanks in advance!
 
I would try the 5.13. I was gonna say 4.86.
 
We ran a combo very close to yours 340 10.4 comp. w2 heads and the same Hughes cam with a 1.6 rocker. 727 with dynamic conv.flashing to 4200 with a 430 gear and 28x10.5x15 mt's. The car ran 7.35 in the 1/8 shifting at 6800. Went with 4.86 reaching for a better 60 ft and more rpm's at top end. The car the same time but picked up 1/2 mph. Won the track points with that setup as the 4.86 made the car more consistant. Always wanted to try more gear but the car was also street driven. I'd say try the 5.13's as Rusty said with the low set 904 but keep the 30x10.5's for now. A 32 in. tire in that combo may be too much tire and actually slow you down. I've seen this many times. Put enough tire to hook consistantly. A big tire while looking cool will slow down a car without enough engine to pull them. Also the 5000 converter may be too much with that camand combo.jmo. I hope this helps.
 
Ok. I will prob run those gears then. I need a new set of slicks and haven't bought any yet so I might just go with a 30-31 max tire as you recommended. Guys at turbo action suggest the 4800-5000k stall. Dynamic suggested 4400-4600 stall. I think with yalls opinions and with what dynamic said I will go on the smaller side of the converter and run the 4400. I've only ran it with the 3500 and 3.91and it wanted more stall and gear imo. Thanks for all the good advice given!
 
Oh and when I get to that point I will need some help setting up and learning a delay box... I've never used one.
 
I do not agree that a 5000 stall is too much. I was running a 9 1/2 4000 stall behind a 360/380 hp crate motor with 5.14 gears and ran a best of 7.46 in the 1/8 at 2950. I put a PTC 8 in race convertor that flashed 5500 and it ran a 7.32 first pass. I was shifting at 5800 rpm. I was running a M/T 315/60 ET Street Radial 30 in. tall on home made Caltracs and stock leaf springs.
 
If it was me, Id leave the 3.91s in there, for one good run and see what it traps at. Then get the exact right ratio by math.
Beats the heck outta doin it twice.
I'd also stick with the 2.45 low gear trans;Narrow powerband,narrow splits.Might be a touch slower on the 60', but will make it up down the road.
 
D-50394 said:
I do not agree that a 5000 stall is too much. I was running a 9 1/2 4000 stall behind a 360/380 hp crate motor with 5.14 gears and ran a best of 7.46 in the 1/8 at 2950. I put a PTC 8 in race convertor that flashed 5500 and it ran a 7.32 first pass. I was shifting at 5800 rpm. I was running a M/T 315/60 ET Street Radial 30 in. tall on home made Caltracs and stock leaf springs.
Click to expand...

I agree. If you're shifting at 6800, you should have a converter that flashes around 5800 to 6000.

Get the best converter you can afford. ATI in my opinion is the top with Ultimate Convert Concepts a very close second.
 
You must log in or register to reply here.
-

Back
Top