Transmission choice....

[70Newport]

So Im at a point where I need to get my driveline figured so I can start mocking things up. I have ended up with a 1969 327 SBC, cool motor for CHEAP! now im torn between shelling out for a 700r4 or just doing a TH400.... i know its 4 vs 3 speed but cant find much info on gears. I will cruise a bunch around town and run 1/4 mile with some friends. Are the gears in the 700r4 different enough on the low end to justify it for what im using it for or will I really just gain overdrive for the highway?....

thanks as always!

 

[dutch]

I`m not a gm guy but for what it`s worth; The Chevy boxes I`ve wrenched on were all 700r4`s. The wrenching mainly involved dropping it because it died...
I`d go 727...

 

[Blue Eyed Devil]

The cost between the two will be nominal, so not much to consider there.

You're leaving out a major factor though - What rear end gear are you using?

 

[Tripper]

No choice IMO... 700R4! Love the low 1st gear & the OD!!! Really nice rebuilt 700 goes for $1,650 here! [cl

BoB

 

[70Newport]

Sorry everyone forgot to include rear end. I have not 100% chosen rear end yet but it will be something with around a 3.89 gear.

These are prices for "good shape" used transmissions In my area but I can pick up a TH350 for about $200 vs a TH400 for $700 vs a 700R4 for $1000+

Didnt really think about the TH350 till the last couple hours when Im finding Rebuilt ones with shift kits and a 2000 Stall for $350.... almost worth it in my head right this moment.

I know very little about GM transmissions. Only ever run 727 or Japanese lol

 

[Old Iron]

The 327 doesn't need a th400 a th350 is more than adequate.
I like a 700r4

TH350 2.52 1.52 1.00

TH400 2.48 1.48 1.00

700r4 gear ratio 3.06 1.62 1.00 0.70

 

[Blue Eyed Devil]

If you're gonna run that tall of a gear you better get an OD trans or it's gonna hate you on the highway.

Tire diameter also factors in, but still. Spend a little extra on the 700 now, or spend a lot of time paying for extra fuel, not to mention wear on the engine.

 

[soltz]

Two more cents

We ran a TH350 in my daughters 70 Camaro with a 4:11 axle, great out of the hole but, at 70 pulling around 4500
Hove Fun [cl
[P

 

[70Newport]

Thanks all! Going to try and hold out for a good deal on a 700r4 or try and figure out what i can pull one out of. If it takes too long ill just go TH 350 and deal with highways hating me lol.

 

[rustybeercan]

Thanks all! Going to try and hold out for a good deal on a 700r4 or try and figure out what i can pull one out of. If it takes too long ill just go TH 350 and deal with highways hating me lol.

700, good decision! Don’t settle for a 350, you’ll regret in IMO!

Beercan

 

[DozerII]

Good Choice, my Essex had a 350T with 3.50 gears and ran 3000 rpm on the hwy at 65mph.

 

[Old Iron]

Any engine (V8 or 4.3 V6) 700r4 '85 up to '92, the input shafts are 28 spline and were stronger trannies than the '83 '84 which had a 27 spline input shaft.
These can be found around here any where from $100 good used to $650 rebuilt

 

[70Newport]

So I did it! Ended up getting super lucky and found a 700r4 that had just been rebuilt through a friend of a friend! They ended up going to a 4l80e with an engine swap so this went up for grabs! Great timing!

Any tips on the install? Parts? Linkage? Torque converter?

Thanks again all!

 

[lowbudget50]

Make sure you get the TV cable set up properly or it wont last long. I had my trans builder help.me set mine up. Not hard, but wanted it right.

I run a 327 with 373 gears in my 50 I had a w350 at first and hated it. I swap the 700r4 into it and have never been happier with it

Good choice

 

[vht]

The 350 if built right is a great trans, I put the one in my 72 chevelle through hell with a stout 434 in front of it and didn't break it, it had a lot of Coan parts in it though. As was said, you need OD, 28 in tire and 3.55 gears in my chevelle and it was spinning pretty good at 60, on the interstate you needed a towel over the tach so you couldn't see it.