[grouch]

The more I read, the more uncertain I get.

The curb weights I've seen listed for late 80's Corvettes range from 3229 to 3890 lbs (see for example http://www.quickperformance.com/Tech...us_measure.htm at the bottom of the page). The "min/max" weight given at http://www.carnut.com/specs/gen/olds40.html for a 1949 Olds 76 are "3260/3945". (I have trouble believing the curb weight of a Corvette is only 55 lbs less than that old 1949 battle wagon fully loaded).

Any opinions on the strength and appropriateness of grafting a Corvette front suspension under a 1949 Olds? Anything that I use will involve some aggravation because the 'hats' for the coil springs on the Olds are part of the frame. It's not as clean a frame as the same year Chevy.

[farna]

The 80s 'vette has crash beams in the doors and a heavy frame. I bet the frame without the body is heavier than the 49 Olds. The 'glass 'vette body offers little support, the Olds body is much more rigid, and has no crash beams. The door skin and the inner metal just under the door panel is it!

The spring pockets and such won't be a problem. In fact, you should probably remove the rear suspension crossmember. You could weld or bolt a bracket to the center of the existing crossmember if it's strong enoug h in the center to support the car. The 'vette IRS (or Jag) has bolt bosses cast into the top of the diff. That bolts to a bracket on the frame. The 'vette uses a leaf spring across the back of the diff cover. The cover is cast aluminum (older ones may be iron) and has a spring bracket on it. You can add leaves to the spring for more weight carrying capacity, or buy a higher rate spring. You'll need to weld or bolt bracket for the trailing arms to the frame of the Olds.

Take a look at my album. There's a pic of the Jag axle I put in my Rambler wagon. You'll need a similar crossmember, just no shock mounts (or a bracket for the diff to bolt to welded/bolted to your existing crossmember). The Jag uses four coil overs instead of a leaf spring. I was able to use four link type trailing arms, but the 'vette uses a different type arm -- you'll have to use the originals. One thing I've added to mine is a brace from low on the diff to the floor of the car. This helps keep the diff from twisting. I bolted the forward end to the floor (unit body) using fender washers and 5/16" bolts. As long as they are tight there should be no problems. I don't think the diff was twisting any, if so very little, but why take chances?

[grouch]

It's the front that I'm worried about. So far as I can tell, the rear of the frame has no unusual shapes to get in the way. The front of the frame forks into a 'Y' just before the crossmember and also has those bulging hats for the coil springs as part of the frame. (Chevies of the same year had bolt-on crossmembers and the frame rails were simple and straight. The springs, hats and shocks came off with the suspension).

*If* a Corvette really is close to the same weight as this old Olds, it might be worth cutting and simplifying these frame rails to get that suspension under there. It's just really amazing to me to look at the bridge girder-looking frame with complete X and the heavy, full body and imagine a sports car being nearly the same weight!

[S10xGN]

Originally Posted by grouch

Any opinions on the strength and appropriateness of grafting a Corvette front suspension under a 1949 Olds? Anything that I use will involve some aggravation because the 'hats' for the coil springs on the Olds are part of the frame. It's not as clean a frame as the same year Chevy.

Bob @ Progressive Automotive doesn't list one, but I'm sure he could build you a crossmember that will work... I have one in my '47 Ford and the fit-up is excellent!

Russ

[grouch]

Originally Posted by S10xGN

Bob @ Progressive Automotive doesn't list one, but I'm sure he could build you a crossmember that will work... I have one in my '47 Ford and the fit-up is excellent!

Russ

Thanks. Looking at that "Sweet Ryde" is what made me start wondering if a Corvette front end would be appropriate for the Olds. It's also good to hear about your satisfaction with the build, because this Olds has a weird set-up that likely would require custom fabrication.

Attached images show the crazy bulge in the frame. (Scaled down from images in my journal, but I think these are big enough to show the problem).

[home brew]

From the looks of that big bulge I think you will have to cut it out to make any kind of independent suspension fit. There may be a universal sub frame manufactured by someone that could be adapted to your fame. Or - you may be able to cut out the bulge and build up the frame in that area to mount a different independent suspension. A lot of the manufacturers are building front sub frames for lots of different models and may have something that will work. Time to get on the phone or email them to see what they suggest. You don't have to buy what they offer but they may give you some ideas.

[grouch]

Originally Posted by home brew

From the looks of that big bulge I think you will have to cut it out to make any kind of independent suspension fit. There may be a universal sub frame manufactured by someone that could be adapted to your fame. Or - you may be able to cut out the bulge and build up the frame in that area to mount a different independent suspension. A lot of the manufacturers are building front sub frames for lots of different models and may have something that will work. Time to get on the phone or email them to see what they suggest. You don't have to buy what they offer but they may give you some ideas.

I was afraid there would be no magic to get around that bulge. All of the kits I've seen are attached to nice, clean, straight frame rails.

After getting some more junk out of the way, I got a better measurement tonight. It's 57-3/8" mounting flange to flange, along the centerline of the spindles. That makes it very close to the Progressive Automotive kits. I'm going to confirm that everything is symmetrical with respect to the centerline of the frame and then pull everything off the driver's side, down to bare frame. It may be that I can cut out the section that includes the bulge and replace it with straight rails.

Know any place to get dimensioned drawings of a Corvette front end?

[home brew]

I don't know where to get dimensional drawings of a Corvette front end but I bet some of the Corvette owner members on here do.

[grouch]

I sent an email to Progressive Automotive with quite a bit of detail and pointing to several images. Bob Shetrone was very quick to reply, but we don't seem to be communicating. He wants to design a complete front clip, from firewall forward, while I want to replace only that which is in the way. He didn't send the requested dimensions needed for me to plan the modifications to the frame for the kit, but instead requested those needed to design the clip (he attached a pdf that is essentially the same as http://www.progressiveautomotive.com/railstech.htm ). Since he seems unwilling to share even the rough dimensions of the suspension kit, I'll just have to take the longer, possibly more expensive route of working it out myself. (If I have to dig around in a boneyard to get those dimensions, I might as well shop for the parts there, too).

I had to put this project off for nearly 30 years to deal with other people's needs. If I had wanted it built for me, it could have been done before. The finished car is not the only goal. Building it myself is just as important to me. I'm not willing to concede, just yet, that the problems with the frame and front suspension are so big that I have to turn that whole section over to someone else.

Attached: some clearer images of the frame, with background removed.

[home brew]

Who knows, maybe once you get to see what that Covette front suspnsion looks like and get a measure on it it may clear that hump.

[S10xGN]

I can see why he'd prefer doing a complete front clip! By cutting off those bulges, there'd be little left of the frame rail. Even with a steel fixture tacked in place, I'd be afraid the rails would move around while cutting out the bumps. Also, keep in mind the front (engine) crossmember will be replaced - it's a necessary part of Bob's kit either way you go.

Here's a pic of my mock-up with Bob's crossmember in my '47 rails...

Russ

[grouch]

Originally Posted by S10xGN

I can see why he'd prefer doing a complete front clip! By cutting off those bulges, there'd be little left of the frame rail. Even with a steel fixture tacked in place, I'd be afraid the rails would move around while cutting out the bumps. Also, keep in mind the front (engine) crossmember will be replaced - it's a necessary part of Bob's kit either way you go.

Here's a pic of my mock-up with Bob's crossmember in my '47 rails...

Russ

I wasn't proposing just cutting off the bulges; I had in mind doing something similar to what Progressive does for rear suspensions. The front suspension could be mounted on 2 short rails which would either fit inside the existing rails and be welded before removing the bulges, or be a replacement section just for the area of the bulges. In either case, as much of the existing frame as possible would be preserved.

Nice setup in your photo. Could you give me the exact location and a schedule of times when you won't be around? I think I could use a frame jig like that!