Transmission choice

[Bonnewagon]

I'm considering converting my '83 Bonnewagon to an automatic transmission. I have a T-350, T-400, and 200-4R at my disposal. The motor is a tight Pontiac 301 4 barrel. The T-350 would be a perfect easy fit. But since I will be using this wagon for towing a small boat I would think the heavy duty T-400 would be a better choice. I have a T-400 cross member, and don't mind getting a new drive shaft. Friends have claimed that would be "overkill" and "a waste". Why? What are the downsides? Could it hurt the motor? Would it not be a bulletproof set up?

 

[pontiacgp]

The gearing is almost the same and I don't think you'll have any problems with the T-350. It's lighter than the T-400 and takes less power. The T-400 is stronger but the boat your pulling won't hurt the T-350.

 

[Longroof79]

Mark,
I agree with Steve, the TH350 would probably be a better choice behind the 301 than the TH400. The 400 is better suited behind a big block, or large cubic inch engine. The 200-4R would be nice if you do a lot of highway cruising, but I assume the car is used primarily for schlepping is overdrive would not be necessary.
Other than overdrive, the other advantage of the 200-4R would be a lower 1st gear.

 

[Bonnewagon]

Jack, I was really wanting the 200-4R but my rear gears are 2:78 so that would have to go. The only other gears I have for the 7.5" rear are 3:23's. Steve, how much power would I lose using a T-400? Would it really matter?

 

[Texas82GP]

Considering they put TH350's in 1/2 ton trucks I would think a TH350 could handle towing anything the 301 could handle. I'm an overdrive man myself but I don't know how well a 200 4R will handle towing.

 

[Bonnewagon]

Yeah, the T-350 would be a painless swap and probably work just fine. In fact, it was originally paired up with the current 301. They are both from a '79 Firebird Formula I built for my daughter when she was in college. She wrecked it and I kept the freshly rebuilt drive train. I just thought the T-400 would be better somehow. I've been described as a "belt and suspenders" guy, among other things I can't print.

 

[pontiacgp]

Whatever you decide don't get rid of the transmission or the set up for your manual just in case you get bored of the automatic..and you can be rest assured I never called you any name you could not post....😀

 

[Bonnewagon]

"You can call me whatever you want- just don't call me late for dinner". My motto. I was "supposed" to get an '04 Tahoe from my daughter's boyfriend that would be dedicated to boat towing and beach buggy duty. Still waiting. Either way I guess if I ever decided to get rid of the Bonnewagon it would be easier to unload as an automatic.

 

[MrSony]

Th350 is best with your gears. Th Th400 is fine, but takes more power to move and might be a tight fit in the transmission tunnel because it is a physically bigger transmission that never came in our cars. Those almost by definition are big block transmissions or very high torque small blocks.

 

[WARPed]

I would love to find an 82 or later long roof G body, just need to sell my 94 Formula to free up the cash.