Inpheksion

Hello, my father is restoring a 65 SS, and we got a 4L80e at a swap meet recently. I have been trying to find some threads specific to the trans, but all I could find was threads detailing the engine swap. My question is has anyone done this trans swap before, and does it require cutting up the floor pans? Any input would be greatly appreciated.

superdave84

I can tell you that my 4L60e fits fine in my '65 without any modifications. Not sure of the size difference in the 80 though.

67Skylark

That’s going a tough one to answer. It really depends on how your motor sits. I have a 67 skylark that started life as 2 speed, then swapped to the TH400, then on to the 4L85E. I did have to dimple the tunnel for the cooling lines, also several hard taps to fit the dipstick tube. My motor is as low as you can go, I had to purchased the S&P modified F body oil pan to get as low as I could. It’s very tight and I would not think your tunnel is any bigger than my, most just find it easier/cheaper to cut and weld. Big difference between the 60 and 80.

BigEd_72455

iTrader: (7)

I would say that unless you don't mind it almost touching the ground, you will need to modify the trans tunnel.

the 4L80E is a slight bit longer than a turbo 400, but just as big around. I had to go totally custom on the trans mount for my 93 S-10 and I had to lift the cab to get my motor and trans in together. Its a big sucker.

Modding the floor on a street car, especially a classic car is completely up to the owner, not the public. If he has no problem breaking out the sawzall and hacking the floor pan, have at it. Like the old saying goes though, measure twice, cut once. But if it aint big enough, cut more..

Good luck in the build. Also, does he have a controller for the trans, or is he running efi and kept the connectors?