i just rebuilt a th-700r4 tranny with blue plate clutches,corvette servos, boost sleeves, and a shift kit. I'm gonna put it in my 81 z with 3.73 in the rear i know it has the extra low gear but i was wondering if any1 knws if it will feel like the gears are spaced too far or will the 3.73 prob make up for it. it has a 350 with around 380 hp and a fair idle it'll be used mainly forthe street but i wanted od for the occasional trips to the drags....i was also wondering if it'll help/hurt my et's. thanks

 

I was running a 700r4 in my 72 a few years ago but had 3.42 rear gears.In 1st,it felt like a 4.10 or higher rear gear but overdrive would kick it down to feel like a 3.08 allowing decent mileage.I had a built 350 with about the same HP as you and loved it.
If you don't already have a driveshaft,I have my old one already shortened and balanced.I kept it when I sold the car(w/original trans) but am going with a 6 speed this time.Let me know if you need it,cheap.
Good luck,Joe

 

I have a '70 with a hot street small block. I run a 700r4 and 3.73 with 275/60r15 rear tires. No times as of yet, but the seat of the pants-o-meter tells me it's tons better than the 3.08 I had before. Although I cruise at 2300rpm on the freeway now instead of 1900, it's worth it and even gave me better mileage than before. Go figure.

It also helps to lesser the rpm drop between 1st and 2nd. Very important. It also launches like a mother. Fun fun fun.

 

Ditto on what everyone has said.

 

Heres some "FYI" about putting a Ford Motorsports aluminum driveshaft in a 2nd gen (taken from another board).

"ford aluminum driveshaft in a 80 camaro w/700r4

Ok, gentlemen. I did some reconstruction from my head, with the help of Google.The driveshaft, FMS-M4602G, available from Summit for $159.95, is 45.5 inches center to center. My current driveshaft is 45 9/16 center to center (behind the T56, that is), so it ought to be the right length.The trans yoke is the standard 27-spline TH-350 yoke, which also fits the T56 and 700R4. This yoke requires a Saginaw 3R U-Joint. The Motorsports driveshaft takes Spicer 1330. The conversion U-joint(3R-1330) is Spicer 5-212X.
The pinion yoke for my 1980, stock Z28 rear (3.42 limited slip) requires the same U-joint.I've ordered the driveshaft, so by the time I get back (late next week), I should have it, and then I'll know. Hopefully, I didn't miscaluclate. []Back when I had my stock driveshaft shortened for the conversion, I spent $78 (which included balancing). This whole deal should come in just under $200, which is compelling for a 3.5" aluminum driveshaft.Todd


Well, I ran into a small problem- my fault.The rear U-joint, that I stated above, is not correct. I looked at the pinion wrong. The pinion requires the same Saginaw 3R style U-joint as the front.So, both the front and the rear use the Spicer 5-212X, conversion from 3R to 1330. Here it is:
In the photo, the vertical portion, with the grooves for the clip on the inside, is the Saginaw 3R portion. The horizontal is the Spicer 1330 portion (clips go on outside, in grooves on the driveshaft). The width of the U-joint is within .03" horizontally and vertically, so there should not be any strength compromises.I picked this one up at the local NAPA- NAPA P/N 355. $20.99 each.As for the driveshaft, it is the EXACT same length as mine- 45.5". Here they are:

The stock shaft is 2.76" in diameter, while the new shaft is 3.52" in diameter. Under the car, the H-pipe is just over 1" away from the shaft, with the rear suspension fully extended down. With the new shaft, it will come within 1/2", but still should clear. I can't see any other potential clearance issues."

 

thanks for the info i might just go with the aluminum driveshaft...i'm putting higher shackles on the back so that should stop clearance probs...i didn't think it costed $78 to get a driveshaft shortened and balanced so i guess i need to check into other alternatives... all i have to do know is figure out what he meant with all the different yokes but it can't be too hard to understand.

 

I should have edited a little bit!