Transmission Help

[rockman20]

Okay, I need help here. I just bought a used 1982 Chevy Scottsdale from a private owner. The truck use to house a 6.2L diesel which the owner before the guy I purchased the truck from swapped out for a SBC 350.

Here is the problem. The truck is fitted with a TH700R4 and I am experiencing what I thought at first was early shifting. After having a few transmission shops look at it, they all agreed that it is the torque converter locking up too early. It locks up at about 30MPH. I was told to replace the TV cable on there. What do I replace it with? Do I get one for a diesel or a gas?

Does this sound right to anyone on this board? I would think that something would need to change internally since the transmission should be setup to shift differently if it is now setup behind a gas rather then a diesel.

I will have many, many, many, more stupid questions in the future here, but let me start with this one first.

I'm a newbie on this form so take it easy on me!