I was wondering if they put anything special behind these motors in a stock application? i would think that the trans would be heavy duty to hold up to the miles of a diesel motor. The 77 i had many years ago had a turbo 400 behind what i thought was basic 350 until we looked into it and found it to be a diesel motor converted to gas.i wish i had paid more attention to the numbers on that block and heads etc.

 

I highly doubt it. The 350 diesel was much weaker than the Olds 403 in those years in torque production. I saw a fair number of diesel swaps some with the original heavy duty diesel starter and flex plate, some with the the gas starter and flex plate. Pretty sure the 80's Deta 88, converted from a DX to a 307, I worked on had the original TH350C which was the only trans to come behind them in those years, I believe. No TH200 or TH2004R as an option behind the diesel. I never saw either of them but these cars were 15 years old at the time.

 

i believe the only difference was in the torque converter,and possibly the governor.

 

I think my 81 Delta 88 had a turbo 400. I wishing I had checked to see if it was a D or DX block. I never worked on it because I had a guy who was a diesel mechanic and charged me no labor as long as I had it. The reason was I sold him a fully documented 64 1/2 mustang one owner car that I bought to restore. He was working on the diesel we went to my shop and he made the offer on the diesel car free labor. The mustang was going to be his daughter's graduation present. He had 12 months and he got the job done on that 64 1/2. I let him buy the mustang at what I paid for it. I only had that mustang 7 days. Knowing now I didn't get a good deal back then. But a young girl got the car she wanted that was special.She wanted a 65 mustang lol.

 

81 should have been a dx block,and the only 5.7 diesels i have ever seen with a th400 were the pickups.

 

My 81 custom cruiser was a dx with th350c and a 8.75 12 bolt.

 

When I swapped in the 455 to replace the diesel 350 engine in dads 81 GMC I REALLY wish I had swapped converters. The factory diesel converter has a very low stall, probably around 1600, and the trans shifts around 3500rpm. I’m sure that was perfect for the Diesel engines, not so much for gas. It’s a good thing 455 engines are torquey, it does very well considering the mismatched parts.

I have a 700 rebuilt and ready to go, all I need is for life to slow down long enough to swap it in.

 

It wasn't just diesels with the super low stall, trucks in general. My car TH350 also stalled around 1600 rpm. My 2004R D9 converter, all of them around 1900 rpm. When I had my 94 Z71, when I picked up a rebuilt 4L60E, probably with a truck replacement converter, it stalled around 1500 rpm. The factory shift points were low 4000 rpm, perfect for a 5A 307 headed Olds 350. The 3.07 first and 3.73 gears with the 454 TBI launched pretty hard for what it was, I could spin both grippy tires pretty good. With a gear swap, you will be rolling smoke with a 455.