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Rear End Donor

J

jon0249

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I found a rear end from an '87 Camaro with 2.73 gears that I want to put in my '56 TF. I haven't found much on this year model donor - does anyone have an opinion whether this would be a good swap? It will be mated to a T-5 OD tranny behind a 235. Thanks for your opinions.

JON
 
jon0249 said:
I found a rear end from an '87 Camaro with 2.73 gears that I want to put in my '56 TF. I haven't found much on this year model donor - does anyone have an opinion whether this would be a good swap? It will be mated to a T-5 OD tranny behind a 235. Thanks for your opinions.

JON
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it will be plenty strong enough, you just have to cut all the crap off of it and setup for your suspension.
 
High gear ratios on T5 transmissions vary between 0.63 and 0.86 depending on which T5 you use. Once you hook that to a 2.73 rear gear and picking an average of 0.75 for your high gear, you are talking about an effective 2.05:1 in high gear. My guess is a 235 wouldn't have enough guts to push an old truck through the air in high gear with that kind of ratio. Assuming 26" tires that would give just under 1600 RPM at 60 MPH. 4th gear would still net engine speeds of 70% of stock rear end with high gear.
 
That's what I was afraid of. However, I'm rebuilding a 283, which should in my opinion have enough HP and low-end torque to make the combined gear ratios effective. You are correct - the final drive ratio on the T5 is .72

You think the 283 will have enough? It will have a Performer intake, mild cam and other improvements over stock, which should produce around 225 hp. My thought is to go ahead and make the rearend swap and "get by" 'til I can swap engines - can't be much worse than it is now with 3-spd tranny and 3.90 gears. Worst case, I highway drive in 4th gear with the T5.
 
Somewhere around 342/1 is about the limit without the V8.
My AD one ton now has that and the stock 4 speed trans.
Runs down the road just fine, just a little to flat for my taste, however I did think the 410/1 that replaced the 514/1 was still to slow.
 
UPDATE: Finally got everything staged and did the swap over Thanksgiving. Took out the very tired, old 3-speed and column shifter and installed a Borg-Warner T-5 from an '86 S-10. Also replaced the OEM 3.9:1 ratio rearend with a 2.73 setup from an '87 Camaro.

My concerns going in, especially running the 235, were mirrored in your comments - I suspected I wouldn't have enough power in 5th gear to push the pickup into higher RPMs. After a 4-hour road trip, all suspicions were confirmed. I barely had enough power in 5th to maintain 75 mph, much less increase my speed. On hills/inclines, I would have to downshift to 4th for the needed torque. Of course, downhills were loads of fun, going faster than that old jalopy had ever been.

Concern #2 was my biggest fear, that the 235 would just be too weak out of the blocks. The original overall drive ratio in 1st gear was 11.47. With the T-5, the new overall 1st gear ratio is 10.26, and there is definitely an added load on my little 6-cylinder. But as long as I don't have tailgaters at stoplights, I am getting off the blocks just fine, but very much anticipating completing the rebuild of my '66 283ci.

I would appreciate any tips or tricks to squeeze moree hp and torque out of my 235.

JON
 
You can always just change out the ring and pinion in the rear end. thats probably a 10 bolt, they are pretty easy to do if you take your time. You do need a dial indicator for setting the backlash. We do it all the time in our Camaro dirt track stock car. Bruce Kile
 
brkile said:
You can always just change out the ring and pinion in the rear end. thats probably a 10 bolt, they are pretty easy to do if you take your time. You do need a dial indicator for setting the backlash. We do it all the time in our Camaro dirt track stock car. Bruce Kile
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but remeber that its a car 10b and not a truck.

measure the backlash and check the pattern BEFORE you disassemble it.
 
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