hey guys i found rearend with 373s and i was wondering if this is too steep for a daily driver? i heard that if driven right that it might even increase my MPG because the trans locks up faster. is this true? I know that having a cam to match your rear also helps. I have a comp 268, will that go good with 373s?
thanks
Tom

 

Yeah, you could use 3.73's with a 268. Personally I would stick to 3.42's withthat cam. If you still want that rearend my suggestions are track tested in my own 83 Z28. You will have to experiment, cause maybe the weather, track your driving may all be better or worse than when I did it.

3.42 with the 268H and 270H
3.73 with 280H
4.10 with 280H and 292H

for street driving or especially a daily driver, you would not benifit as much in my opinion as you would with 3.42's.

 

By "trans locks up", I assume you mean the torque convertor clutch lockup. That's a function of vehicle speed, not engine speed. If you get the correct speedo gear(s) for the rear, the TCC will lock up at exactly the same speed as it did with the old gears - the engine actually will be turning over faster before it does lock.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1/94.6 @ 5800' Bandimere.

 

Do you drive on the interstate much. Around here the speed limit is 60(I drive a little faster than that) and I rarely see the interstate. 3.73's get me respectable mileage.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

I drove my '84 with the L69, 700R4 and 3.73's
from Orlando FL up to Buffalo NY and back, getting 23 mpg at 70mph all the way (well, a little less in the WV hills). Engine rpm's were about 2,500 at that consistent speed, and the cruise control was broken so it was all up to me.

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DR Stevens
1984 Trans Am 305HO L69
1991 Firebird 305 L03

 

I have 373's and i think there great i get better mileage plus there good off the line.

 

I have 3.73s in my daily driver and I LOVE THEM, no regret here, and they knocked over a half second off my quarter mile.

 

half a second in the 1/4 is a big improvment, great job!!

 

I can't count how many cars I've had that came with them stock, from Chevelle SS396s to old Z28s to .... well, the 83 L69 Z28 I have now.

They're just fine. You may find that they don't improve your ¼ mile time, if your engine won't rev (i.e., if it's TPI); but they'll sure make the car alot more fun to drive on the street.