El Camino Rear End

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lvrnespeca

Not-quite-so-new-guy
May 23, 2019
21
8
I recently bought a 1981 El Camino with a 229 chevy motor. It had a 350c and a 271 rear end. I replaced the 229 with a stout 350 then soon had to replace the 350c with a th350. The rear end rides great. Very low RPMs while cruising and a top end that ill never hit. The Question: What would be the best rear end choice 3:24 or 3:42 I want driveability more than performance!
 
565bbchevy

565bbchevy

Geezer
Aug 8, 2011
6,555
113
Michigan
If your main concern is driveability I would probably go with a 3.08 or 3.23 gear.
Also you can change rear tire height to fine tune where you want to be after gearing.
 
Last edited:
  • Agree
Reactions: ssn696
ssn696

ssn696

Comic Book Super Hero
Supporting Member
Jul 19, 2009
3,859
113
New Mexico
Consider an alternative: trade the TH350 for a 700R4 and a Powertrax lunchbox locker. The lower first gear will make the 2.73 rear feel like a 3.42, and highway speeds will be lower noise and fuel consumption. Requires a lockup kit and a cross member change. The locker can be done on the axle while it's in the car.
 
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lvrnespeca

Not-quite-so-new-guy
May 23, 2019
21
8
I have 2 200Rs Hmm.....
 
jlcustomz

jlcustomz

G-Body Guru
Nov 22, 2011
728
93
In your case , I'd sell the th350 & get an overdrive with a lower 1st gear & a lockup.
This would be the closest thing to the best of both worlds that a modern drivetrain would provide. You'll need a shorter driveshaft & possibly different crossmember , but that's just part of the deal. Not just for fuel savings, an od trans with low ratio rear will give you much more highway comfort. My double OD t-56 /Ls1 in (.50 ratio 6th gear) with 3.73 ratio & 29" tall tires put me not getting to 2000 rpm till 92 mph.
Only other issue that could pop up would be exhaust drone, but that depends on exhaust.
 
H

hoffa65

Master Mechanic
Mar 11, 2019
276
63
Atlanta GA
I have 2 200Rs Hmm.....
200r4 is a direct replacement for the TH350 same drive shaft and yoke you would have to get a cross member with frame extension for the 81, or weld in a mount for the stock 200r4 member. I'm betting you have dual exhaust now so a G-force member would be the way to go. A 3:42 gear with an OD will good all around, I think the 271 with OD and TC locked up would be lugging the motor a bit at cruze, unless you curz at 90+ lol
A fresh build (good hard parts) on a 200r4 with a Transgo shift kit would be my choice, had one in my 84 ElCo with a 3:73 LSD running a 69 327 325HP 2500 stall TC was a FUN ride.
 

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