The Stovebolt Site Forums The Shop Area Engine Shop Torsion bar IFS and G.V. overdrive don't mix on 62. Help!

I'm rebuilding my sm420 and I WAS going to add a gear vendors overdrive. However, the crossmember that lies between the frame rails that is also part of the torsion bar suspension is right where the pan of the O.D. will be once I install it. I frequently run into these type of issues because a few of these vendors somehow think that parts that fit a 63 -66 will fit a 60-62. WRONG. The 60 -62 frame and suspension are not the same. Does anyone have experience with this torsion bar set-up and/or have you modified or maybe fabricated a crossmember that might allow clearance for such an item? What about changing the suspension on this particular frame. For those of you that might know the difference, it is the "X" style drop frame as opposed to the "ladder" frame used on 1/2 tons from 63 thru 87. Do I have other options or am I up the creek? Thanks for the help.

You could go with the discrete GV unit that could be mounted between the transmission output and the rear differential, if there is enough length (more likely a possibility if yours is a long wheelbase truck). It would have a short u-joint shaft between the transmission and the GV, then a one-piece driveshaft to the diff. Do you have a two-piece driveshaft now?

Or you could go with a late-model manual transmission with overdrive.

That's an interesting possibility. I do have a long wheel base. Also a 2 piece driveshaft. Where the X part of the frame meets shortly behind this crossmember(in front of the X) poses another clearance problem. So does the dual exhaust in front of the diff. and just behind the X. What about the main bearing towards the rear of the long part of the driveshaft? I would then have to re-route the exhaust and the O.d. would have to be pretty close to the rear diff. Hmmm Time to call Gear Vendors. It was sold as a bolt-in. I'll chat with them tomorrow and see what they say. Thanks Loco, good food for thought, something that I can ask them when I talk to them. The O.D. I have has an adaptor to bolt on to the rear of the sm420. I imagine they would have to supply me with different adaptors if they have them and my bet is they don't and I'm usually an optimist.

Maybe you could use the separated GV unit to effectively replace your driveshaft's intermediate carrier bearing, with a shorter driveshaft fore and aft.

I think I may have saved some GV install articles from car magazines... I'll take a look for them.

I talked to Gear Vendors today. They are sending me a plate to replace what they call the deep sump. This will buy me about 2" worth of clearance. That deep sump that I call a pan, is overkill for racing and heavy towing. My 261 will do only a little of either. I'm then going to replace the old motor mounts to lift the motor and transmission the remaining 1/4" that I need. I also may have tweek the transmission cover part of the floor to accomodate. If doing that is not enough, the last thing to do would be to somehow shave or notch the top of the crossmember and reinforce it in a different manner to allow clearance. I feel a little better about things today. Now I just have to figure out how to take this suspension apart. If I could only understand the shop manual!

some people change out the front crossmember and use 1963-87 suspension.try www.chevytalk.com

is "gear vendors" a company?? do they have a web page?

I took more accurate measurements today. Even with the new plate, I need one more inch. I'm going to have to take out this crossmember and have 1 and 1/8" inch cut out of the top of the hump and reinforce it with new steel that runs flat. Time to call Buffalo. This will all work, I will start taking pics and document the project. Being that I have anywhere from 2 - 8 hours a week to work on this, it may take a while. Fort Knox, your 61 should have the same frame. Do you also have torsion bar IFS?