[BruceWilkie]

Mine was out by about .029 horizontal and about .027 total on vertical using a chev stick housing. I welded dowel hole shut smoothed things up and redrilled as described above. Still not perfect but .003" total is only .0015" which is close enough.

[gavin]

After another look at my P/G case maybe the measurement does not count and I will have to find another case.The weld is in the worst possible place for my runout measurement.

[Green Elephant]

I’m resurrecting an old thread here with hope that I can get some experienced input or advice. I built an adapter plate to install a 1968 Chevy TH400 behind the 389 in my 63 Grand Prix. The adapter plate is .250 thick 4130 steel, I also machined a crank flange spacer to move the flexplate back the amount needed for proper flexplate to torque converter clearance.
I currently have the engine and transmission installed with a scissor jack supporting the transmission and the engine mounts bolted down. I have heard that installing a TH400 in these cars will take some massaging of the floor with comments anywhere from a few hammer whacks to major floor surgery. I’ve already cut an opening in the floor to clear the tail housing flange and have been jacking the transmission up to see where I’m at with driveline angle. I’ve made several additional small cuts to continue opening up the clearance hole in the floor. I’m currently at a 4 degree downward angle at the crankshaft (measuring off the balancer front face) and would prefer to get to three degrees. To accomplish that it looks like I’m going to have to cut the narrow part of the floor hump back to the front edge of the U-channel support that sits under the floor shifter. This should give me clearance for the transmission and front u-joint. I’ll still be somewhat close towards the top of the transmission hump, (just below the vacuum gauge) but I think that will bring me to about 3.5 degrees. I’m also working on a sheetmetal replacement for the floor that will be installed to provide the clearance needed. My first sheetmetal attempt is already in the scrap bin but I’ll get another one started once I have the angle where it’s needed.
Has anyone else done this install? Can you tell me what modifications were required during your install?

[johnta1]

Sure miss Bruce.


Haven't heard from Gavin for awhile.

I'm sure their are a few here that have done this.