trany conversion


Old 03-02-02, 06:52 PM
matt sittle
Visiting Guest
Posts: n/a
Talking trany conversion

what is needed to replace a 83c10 700r4 with 350turbo short/long mounts crossmembers
please let me know
Sponsored Links
Old 03-02-02, 08:23 PM
Visiting Guest
Posts: n/a

You really don't want to do this swap. You lose on both ends when you swap out a 700R4 for a TH350.

The 700R4 has a low gear ratio of 3.06:1 vs. the 2.48:1 ratio found in the TH350. This means your truck will accelerate SLOWER with the TH350 than it would with the original trans.

The 700R4 is an overdrive trans, with a top gear ratio of 0.70:1 vs. the 1:1 top gear found in the TH350. This means your engine will turn about 30% faster in top gear with a TH350. Your fuel economy will suffer.

Last edited by knuckles; 03-03-02 at 07:47 PM.
Old 03-02-02, 08:45 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,818
I agree, the rear-end ratio in your vehicle is likely also wrong, If it came stock with a 700R4, then you most likely have a 308 or lower geared rear end. You'll need a 273 or higher to get any fuel efficiency at cruising speeds because of the ratio changes that Knuckles mentioned.
Old 03-03-02, 05:50 AM
Visiting Guest
Posts: n/a
I agree 100%. Swapping the other way is a bad idea no matter what the performance guys tell you.

Newsflash: A well built 700R4 will outperform and outshift and likely outlast a comparable THM350.

Beef up your 700R4 with strengthened parts (The original 700R4's were weak) and you'll be fine.
Old 03-03-02, 06:25 AM
jz brake
Visiting Guest
Posts: n/a
drive shaft

i agree with knukle, cheese and joe. if you opt to swap the trans and rear end gears, the drive shaft need to be longer. your best bet will be to beef up the 700 r4

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes