2.73 rear end

[jfnar]

I recently acquired an unfinished project, '81 jimmy that has been converted to 2wd. It has no engine or transmission. I just checked the rear end ratio by jacking up one wheel and spinning it 2 revs and was surprised to find it's less than 3. I checked the net and found that there was a 2.42 and 2.73 available. I believe mine is 2.73. Now I'm trying to get my mind around the best engine/transmission combination to look for. Does anyone out there have info on what was used originally on trucks with this rear ratio? I plan to make a driver, no racing or towing, but I do have some hills to deal with. Should I start looking for a different rear axle? Any suggestions will be appreciated.
Thanks.

[Palf70Step]

If you are running a T350 or T400 and V8, then that rear will be a nice cruiser. But, it will lack any omph from a dead start. If you are doing a OD style tranny, then I would look for a 3:42 or 3:73 rear gear for it.

[Dead Parrot]

Use one of the online RPM calculation sites. Feed in your rear end ratio and tire diameter and get your engine RPM back. Since you are after a driver instead of a load hauler, a smaller tire might be a simpler answer then a rear end change.

[kipps]

The very low ratios were usually paired with the straight six engines. Those engines are torque monsters, particularly right off idle, but they don't rev high. I would look into a built 292, with an emphasis on bottom-end torque instead of HP. It should feel and drive similar to a diesel when all's said and done. A manual transmission will make it all the better.

I'm driving a bone-stock 1981 2wd f150 with a 300-i6, four-speed manual, 2.73 gears, and 28" tires. It's a hoot just tooling around local country roads. The bottom-end torque is unbelievable, and fuel economy is pushing 20 mpg on longer trips.

[1976gmc20]

Originally Posted by kipps

The very low ratios were usually paired with the straight six engines. Those engines are torque monsters, particularly right off idle, but they don't rev high. I would look into a built 292, with an emphasis on bottom-end torque instead of HP. It should feel and drive similar to a diesel when all's said and done. A manual transmission will make it all the better.

I'm driving a bone-stock 1981 2wd f150 with a 300-i6, four-speed manual, 2.73 gears, and 28" tires. It's a hoot just tooling around local country roads. The bottom-end torque is unbelievable, and fuel economy is pushing 20 mpg on longer trips.

One time at the dealer (1975) we got a brand new plain jane C20 in off the transport. I got to drive it downtown to the showroom/shop. It had a four speed manual and it had so much power that as soon as I got it into the setup shop, I jumped out and popped the hood to see what the heck monster engine that it had in it.

Danged if it wasn't a 292 straight six! We obviously didn't see many of those. And most of the new vehicles ran like crap because they hadn't been adjusted for the altitude yet (Colorado Springs).


Actually, I would love to swap out the oil burning 350 in my 76 GMC for a 292

My friend down in CO has his dad's old 1965 K20 with a 292. Only vehicle in the world that I'm jealous of

[mongocanfly]

my 86 had 2.73s.. it came with a 305/sm465
but like stated..work the gear ratio around your engine/trans/tire combo

[kwmech]

My dads truck came with the 2.73s. 1982 1/2t shorty. Engine----6.2 diesel with a 700r4. It has been changed out

[KQQL IT]

I've had 2.73 and also 3.08 in multiple trucks with a 27" tall tire
Any decent engine will pull the gear all day and get decent mileage.

[Scotty-D]

My 85 had 2.73's and a 700r4 from the factory.

I swapped in a TH350 and even with a very stout 383 it was pretty underwhelming off idle (28 inch tire). Now with that being said it would absolutely cruise down the interstate pulling my boat at 75+mph.

I swapped cam/convertor and went to 3.73's but I have to admit that I miss the 2.73's on the highway. Its a fantastic ratio with a 3spd auto if you just want to drive down the highway.

[72c20customcamper]

My 77 burban had 3.08s . With the anemic mid 70s motor and tall gears felt like it took forever to get to highway speed . Living in the north east it was fun hitting some of the mountains at 75 and mashing the pedal down and without even pulling a trailer I'd below 55 at the Crest. But it was nice to cruise at 80 on the flat lands

[Palf70Step]

2.73s were the standard axle for 6 cylinder vehicles in 81. a 2.56 was the standard for V8s. Most v8s were optioned with either 2.73 or 3.08s. Again plan around what engine/tranny and tire combo you have and what you want.

My 81GMC C1500 is a 250 six with T350c and the 2.73 rear gears. It does fine, but definitely not a hot rod off the line.

[photo-tom]

I have an 84 with a 305/350 2.73 from the factory. Just swapped it out for a 3.42 and love the pep it gave in the little motor. I do suspect it will be a bit less comfy on the highway, though.