Automatic Overdrive Transmission Advice
Moderator
Joined: Jul 2007
Posts: 18,221
From: Edmond, OK
That's a bummer that your TH350 finally bit the dust. Let us know how that 200-4R install goes.
I drove the C6 in my 86 F250 until it died. I tested the pressures and even manually shifted it between D, 1 & 2 for a time before it croaked. The 4T60e in my 96 98 died at the same time and I decided to have the C6 rebuilt. The rest is history.
I drove the C6 in my 86 F250 until it died. I tested the pressures and even manually shifted it between D, 1 & 2 for a time before it croaked. The 4T60e in my 96 98 died at the same time and I decided to have the C6 rebuilt. The rest is history.
Thread Starter
Registered User
Joined: Jul 2024
Posts: 45
From: Rock Hill, SC
Move the crossmember to the TH400 position, reuse the drive shaft and get TH400 emergency brake cables. Speedometer hook up is the same, will just need the right gear combo and get whatever lock up control appeals to you most. The 2004R is an easy swap in place of a short tail 350. Shiftworks for the shifter modifications, I believe and get a converter to match your current cam specs. About the lowest I have seen from a 2004R stock converter is 1900 rpm flash stall. Tell Extreme where you want WOT shifts, stock is 3000 rpm to low 4000 rpm for most stock 2004R trans, obviously needs modification, not hard, just trial and error. Good luck.
'72 Cutlass ragtop
Joined: Jun 2016
Posts: 1,315
From: Tampa, FL
I thought about going the built 2004R route when my previous local-built TH350 broke a few months back - I'm running a 3.08 posi gear on a 400hp roller cam 350 motor. So for 2 reasons I decided on another TH350:
- TV cable adjustment is crucial to 2004R life and I didn't want to deal with the prospect of having one fall out of adjustment for any reason
- I didn't want the added expense of having to upgrade my posi ratio to better align with the 2004R gearing
So I ultimately went with a TCI Street Fighter TH350 and the recommended SF series 2400-2600 non-lockup converter for it which turned out to be an awesome combination - I'm pulling just over 3k rpm at 70mph on 245-50-R17 tires and to me at least, it's not all that noisy relative to expectations from any other old car.
- TV cable adjustment is crucial to 2004R life and I didn't want to deal with the prospect of having one fall out of adjustment for any reason
- I didn't want the added expense of having to upgrade my posi ratio to better align with the 2004R gearing
So I ultimately went with a TCI Street Fighter TH350 and the recommended SF series 2400-2600 non-lockup converter for it which turned out to be an awesome combination - I'm pulling just over 3k rpm at 70mph on 245-50-R17 tires and to me at least, it's not all that noisy relative to expectations from any other old car.
Last edited by 70sgeek; May 14, 2026 at 09:37 AM.
Thread
Thread Starter
Forum
Replies
Last Post
