Scott I talked to a transmission guy at a Good-Guys show last summer who said they could provide a 4L80e to fit my Cadillac. I would imagine that same trans would fit your Olds and cost would be similiar to the Tremac.
I'm bulding a truck to pull a trailer. From the sound of your transmission choices I think you are building a hot rod. We'll deal with similar issues, but likely choose different solutions. Right now I plan to use the TH400 because I have it and don't want to spend the bucks for the OD automatic.
I've considered a Tremac for my old 'vette, but as you say money is tight and I'm just glad I don't feel the need to sell any toys!
