Do 4.30 gears need 5th gear to make the 1/4 mile?

93 Cobra needs input · 10-07-2002, 08:28 PM

I want to finalize my rear end for drag racing over the winter and want to know if anybody here knows if with my setup and 26" M/T slicks 4.30 gears will get me to the end of the 1/4 mile with out shifting into 5th gear. I suppose 28" Goodyears would help the rpm's?? I want to keep the Victor Jr heads in the high rpm's and have solid internals to rev the stroker to 6,800 maybe? If I leave the line and hook I'd rather have 4.30 than 4.10, but I don't have any experience with either of these ratio's but like always I'm sure someone here does. I have a tremec TKO if that matters,Thanks

Rick 91GT · 10-07-2002, 08:41 PM

With the 4:30's depending on how much you hook and how much power it builds should put you in the 6500-6800 trap you are looking for. The 28" tire will have less sidewall deflection if your car is voilent off the line, and will drop the rpms about 300-400.

In your sig it says S-Trim soon...you will only want a 3:55 gear then.

88workcar · 10-08-2002, 05:01 AM

I run a tremac and 4.30s, right now with 28.5 tall tires I cross at about 5500 in fourth @ 108mph. With a 26 inch tire two years ago I was running 112-113 and crossing at 6000. With a shot of nos on top of that I was looking at the shift light long before the finish line

Jeff Chambers · 10-08-2002, 06:32 AM

4.56's and 26" tall slick put me through the traps at about 7100rpm at 121mph. If I were still a stick car, I'd never consider shifting to 5th (on a 5-speed transmission anyways). The 5th gear is very weak and its underdrive becomes a torque de-multiplier.

You'll need to set your sights on what kind of performance you aim to get out of the car and then select your gearing based on that MPH, the desired rpm at the stripe (usually about 400rpm above peak HP), and the size of tire you'll be using. Gearing is everything so do your homework.

USMC302 · 10-08-2002, 11:19 AM

I cross the line at 5800 with 4.10's

bigblockcoupe · 10-08-2002, 12:52 PM

if your going with a supercharger soon get a set of 3.90's i had 4.10's in my supercharged '93 cobra and I also have a tremec and i had to shift into 5th with the 4.10's now I have 3.73's and they are alot better but i could probably get away with the 3.90's and still stay in 4th through the traps.

10-07-2002, 08:28 PM	#1
93 Cobra needs input Registered Member Join Date: Oct 2001 Location: Madelia,MN USA Posts: 58	Do 4.30 gears need 5th gear to make the 1/4 mile? I want to finalize my rear end for drag racing over the winter and want to know if anybody here knows if with my setup and 26" M/T slicks 4.30 gears will get me to the end of the 1/4 mile with out shifting into 5th gear. I suppose 28" Goodyears would help the rpm's?? I want to keep the Victor Jr heads in the high rpm's and have solid internals to rev the stroker to 6,800 maybe? If I leave the line and hook I'd rather have 4.30 than 4.10, but I don't have any experience with either of these ratio's but like always I'm sure someone here does. I have a tremec TKO if that matters,Thanks __________________ 331 stroker, JE 8.5:1 pistons, H-beam rods, steel crank, main cap, msd with 3step, BBK ceramic long tubes,TKO, 4.30's, motorsport Z303, Victor Jr aluminum heads, crane gold 1.6, southside lift bars, 90/10 front, 50/50 rear, centerforce dual friction clutch, Vortech S-trim soon.

10-07-2002, 08:41 PM	#2
Rick 91GT Procharged! Join Date: May 1999 Location: Hanover, PA Posts: 1,539	With the 4:30's depending on how much you hook and how much power it builds should put you in the 6500-6800 trap you are looking for. The 28" tire will have less sidewall deflection if your car is voilent off the line, and will drop the rpms about 300-400. In your sig it says S-Trim soon...you will only want a 3:55 gear then. __________________ *D/R 10108 NMRA Drag Radial, 25.5 chassis, F1R* *Check out RNH Performance Performance Engines and Custom Fabrication.* *From Mild to Wild we can build what you want, when you want it.* FOR SALE Stainless Steel Torque Box Supports

10-08-2002, 05:01 AM	#3
88workcar Registered Member Join Date: Oct 1999 Location: Pierre Part, La. U.S.A. Posts: 1,850	I run a tremac and 4.30s, right now with 28.5 tall tires I cross at about 5500 in fourth @ 108mph. With a 26 inch tire two years ago I was running 112-113 and crossing at 6000. With a shot of nos on top of that I was looking at the shift light long before the finish line __________________ 88workcar 1988 Mustang LX 342. 417rwhp @ 6800. 28 X 10 ET Drag, 4.30s, 10.69 @ 126.43 1.42 60ft. 11.13 @ 127.7 on BFGs 1.72 60ft Rice Hater # 42 To be old and wise, You must first be young and stupid I'm somewhere in tthe middle.

10-08-2002, 06:32 AM	#4
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	4.56's and 26" tall slick put me through the traps at about 7100rpm at 121mph. If I were still a stick car, I'd never consider shifting to 5th (on a 5-speed transmission anyways). The 5th gear is very weak and its underdrive becomes a torque de-multiplier. You'll need to set your sights on what kind of performance you aim to get out of the car and then select your gearing based on that MPH, the desired rpm at the stripe (usually about 400rpm above peak HP), and the size of tire you'll be using. Gearing is everything so do your homework. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

10-08-2002, 11:19 AM	#5
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	I cross the line at 5800 with 4.10's __________________

10-08-2002, 12:52 PM	#6
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	if your going with a supercharger soon get a set of 3.90's i had 4.10's in my supercharged '93 cobra and I also have a tremec and i had to shift into 5th with the 4.10's now I have 3.73's and they are alot better but i could probably get away with the 3.90's and still stay in 4th through the traps. __________________ Rice Haters Club member #68 '93 Cobra 10.20@135 '89 Gt Coupe 12.20@115

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