th400, th350, or 700r4

[berencam]

Alright so my transmission gave up the ghost couple days ago..... i had reverse and that was it... lol soooo... im currently shopping for a new trans.... do i get the th400 rebuilt that i already have in it. Do i buy a rebuilt th350 with redline clutches and a stock converter for 400 or do i search for a 700r4. The motor is producing around just shy of 400 hp, and just over 400 torque, so any of the three will handle my engine just fine. I was leaning towards the 350 since it takes a little less hp to run, and the first gear is a hair higher than the turbo 400. I will not be doing much towing with this and i dont really care about highway cruising speeds because this isnt my main vehicle. opinions? comments?

[LEEVON]

if you're not stuck on o/d why not just rebuild the TH400? It's the strongest of the three.

[Sinister]

Originally Posted by LEEVON

if you're not stuck on o/d why not just rebuild the TH400? It's the strongest of the three.

This would be the least amount of hassle. The TH400's are pretty stout in good condition. If I was going to go through the trouble of swapping to a different transmission I'd want overdrive.

[berencam]

The only reason i was even considering swamping to a 350 was because it takes a little less hp to run and it bolts right up, and the last reason was i found a rebuilt one ready to install for $400. If i have my turbo 400 rebuilt it would cost more than $400?

[Sinister]

Originally Posted by berencam

The only reason i was even considering swamping to a 350 was because it takes a little less hp to run and it bolts right up, and the last reason was i found a rebuilt one ready to install for $400. If i have my turbo 400 rebuilt it would cost more than $400?

Driveshaft will need work to swap. The yoke is different and I believe the length is different too.

[capev86]

in this day and age, an overdrive trans is the way to go. long highway drives and gas over 3 bucks a gallon make it the natural choice. with the aftermarket support and good common sense a 700-r4 can have a very long happy life in a working man's truck. or you could maybe get a 4l80 if you need something bulletproof.

only reason i don't have an overdrive in my 72 burb c20 is i want to keep it a 3 on the tree. i did pick up a 66-69 saginaw w/ borg warner overdrive to retrofit into my truck eventually. right now with the stock 307 w/ a q-jet and 4.10 rear swapped in i'm getting around 13mpg on mixed driving. around town it is great but long highway trips are still not much fun. when i get my 406sbc swapped in i'm REALLY gonna enjoy that overdrive!

[68Stepbed]

A TH350 has a different yoke, the trans x-member will need to be moved, and it's usually a different length, depending on which TH350 tailshaft you end up with. If I were spending the money, I would go for the OD. The lower first gear will help with overall pickup speed and the OD will help with freeway speeds.

[cdowns]

for a switch to TH350 you also need to get a kickdown cable setup add to that driveshaft and other misc changeover expences and you're a good bir beyond your $400 install price

[chris71]

a built 700 will cost the most out of the 3, i think you are looking at at least 1000$ for a nice built 700, and if you do the math behind it, unless you drive your truck alot of miles everyday, then most of the time its not even worth it, plus the 700 has the touchy TV cable, that controls shift points and fluid pressure, if you screw that adjustment up you can blow the transmission in a few months.

My vote.......rebuild the 400, its beefier, you dont have to mess with shortening the driveshaft, re-drilling holes in the frame for the 350 position tranny mount, and unless you are drag racing and worried about every tenth of a second, dont worry about a better 1st gear with the 350, i have had several 350's cases crack on me and am sick of them, i am considering a 400 the next go around.

[raycow]

If you don't do any highway driving, the TH400 is a no-brainer. It's the strongest and it's the easiest since you are already set up for it.

Ray

[berencam]

thanks guys. decided to run with the 400.... its at the shop right now. going to have them put a manual/automatic valve body in it.... should be fun...