C4 Corvette Subframe DOM tubing

[Oklahoma_k5]

I've been hiding in the shop working on a way to put 84 Corvette suspension in my 52 Chevy. I found a couple of ways to do it but I didn't want to spend $800 on square tubing. Especially when I have a tubing bender, press brake and metal laying around.

I'm trying to post up a few pictures.



Made from 3/16 plate, some 1 3/4 .120 wall DOM, and the bent pieces are 1 3/4 .090 wall DOM.

Have a few details I'm still working on. I still haven't found out if the lower A Arm mounts are level front to back or if the whole assembly should be tilted back in the truck frame.

Any thoughts?

[Oklahoma_k5]

http://photobucket.com/AMCustoms

[Oklahoma_k5]

[mknittle]

Verrry interesting!

[crossfire84]

That looks scary.

[Oklahoma_k5]

???? Good scary, or bad scary?
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[coralhead]

Can't tell but are the bolt mounts on the upper "A" arm sleeved though? It would be hard to keep the bolts tight if not. The tube can callapse. Just a thought.

[Oklahoma_k5]

Yep on a crush sleeve in the upper mount. Plan right now is to hole saw the frame and raise the subframe into position through the holes. If I sleeve them now they won't slide through the frame.

Upper mounts will be supported by the frame till the top two or three inches.
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[Oklahoma_k5]

Pic of my truck I'm working on, I was looking for a cheap set of wheels and tire on craigslist for mock up. The ones I found just happened to be Boyd coddingtons. Can't go too far wrong with what I paid. So I got the wheels home and had to throw them in front of the old wheels to see what it looked like.

[papastrk]

I don't think you could go wrong leveling the lower control mount tubing with the frame set at ride height. I would gusset the lower control arm tubes to the two main tubes and add a couple of short pieces of tubing between the two main loops for added strength. You know how bad the roads here in Oklahoma are. Those lower tubes are going to take a beating! I would be real nervous about possibly tearing one out. May never happen, but I would engineer for the worst case. Everything looks very nice so far. Keep up the good work.

[robin58]

I've got a question... how are you going to weld that to your frame? I have installed a C4 crossmember from Flatout Engineering and the top control arm mounts about 1/2" inside the outer edge of the top of the frame rails and about 1" or so above it for a decent ride height. Your tubing is going to run through the middle of your frame rails.

[robin58]

BTW because I realized my question may not have been clear, look at the attached pictures (I apologize for the sketch but my AutoCAD wasn't cooperating this morning).

The yours.jpg is how it seems to me you would have to cut into your chassis to fit your crossmember, the 2.jpg is how a crossmember from flatout or progressive would fit. IMHO the way yours appears it would have to mount doesn't give you enough of a weld area.

[mr48chev]

Interesting, are you going to put some gussets on the lower control arm bracket tubes or rely on the limited area of welds you have? Right now that looks like a potential trouble spot.

[Oklahoma_k5]

This may give an idea of the way the tube work goes through the upper flat of the frame. Because of the way the tubes curve the lower frame flat does not turn out looking as clean. Had to trim the frame back and make fill plates. Also had to notch the frame behind the rear upper mount to make room for the upper a arm.



The frame has sorta been turned into Swiss cheese. I thought I planned my cuts better than this. Of course cutting a big hole in it to clear the rack and pinion doesn't help. I'm planning to box the frame from front to back. Based on the previous comments and the way the frame looks I'm going to add a 90 degree bent piece of tube from the ends of the lower control arm mounts up to the frame.

The other thought is that the only time the sub frame should be holding the weight of the truck is when the truck is on a jack. The coil overs or shockwaves (haven't made up my mind yet) will be taking the weight then transferring it to a bracket on the frame.

[Oklahoma_k5]

I put a bunch of other pictures on photobucket. I'm not going to take the time to link all of them.

http://photobucket.com/AMCustoms

If you are in the area and need something from the factory suspension it currently has an appointment next week at the scrap metal yard. I hate to scrap it all out, but I'll never use it. So if you need something it you can have it.

I think the threaded swing shackle pins are COOL. 60 years old and they threaded out by hand. I have to beat the bolts out of my 87 K5 and they've been in and out more times in the last 10 years than I can count.

[Oklahoma_k5]

I Added 10 or so more pictures to the photobucket account. Finally got the new rear frame mocked into place. Just got a couple of bolts for now. Also got the front coil spring mounts made and sorta in place.

Shockwaves are out. Without the factory Corvette sway bar it might have been possible. With the sway bar in there the 6.5 inch diameter shockwaves were not going in.

Coil overs are still not going to have very much clearance on the sway bar end links.

I wound up building a new rear frame section that starts at about the front cab mounts. The old frame had a massive rust hole under the front shackle mount. In order to put the frame at the ride height I am planning for was going to require a c notch to be put in. Then I would need to box the frame to get some strength back from all the cutting and welding. Adding all this together made $100 worth of 2x4 and 2x6 11 gauge tubing seem like a good investment. Making my own rear frame also lets me keep the Corvette Rear Toe adjustment bar in the factory Corvette location. The old truck frame was going to require the use of toe bar flip kit.

Putting the two frame halves together was a challenge. Had Dad come up and help run the tape measure. Dad can build anything with wood so he is a little out of his element but its great to have an opportunity to work with him. I figure if he can build a house that doesn't lean one direction or the other he can help me build a truck that hopefully doesn't lean either.

I have a Laser Level that is one of the most used tools in my shop. Its kinda my poor mans Faro arm. I still haven't figured out why the frame was not straight. (Besides the obvious reasons of being built using a chopsaw and shop floor) I may have to draw a picture to explain what it was doing but I could x it out from matching spots with equal measurements but when i Put the Laser down the middle of the frame measuring side to side at the front and back the middle was off to the right nearly an inch.

In the end I wound up strapping the frame down to the floor using the floor anchors I've had in the floor since the shop was built but have never used before. After strapping it down i was able to pull it into alignment then heat a couple of spots. Now any way that I measure it it seems to be level, square and straight.

Now its time for a few more crossmembers. putting in the rear suspension and a trip to alignment shop for a preliminary check to see if this combination will align. I know it will have to be aligned again when its complete but at least I'll know if there is something to change before finish welding.

[Oklahoma_k5]

Its always great the things that find their way into the shop and windup in the background of the pictures. Notice the extra toilet next to the fan. That's going to be our candy bowl for trick or treating next week. The best part is we are going to a friends house in an upscale neighborhood and the toilet is their idea.

[NEWFISHER]

Very interesting. Being a K5 guy and an off roader , let triangulation be your friend. Mabey gusset the tubes as the come up through the frame? I'm sure from an engineering standpoint it works, but visually it doesn't flow or look strurdy. Its different, weird, etc but I keep going back to the begining and looking again (3 times so far) its like spandex, I don't understand why but I keep looking lol. just my opinion, but I do think its cool.
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[Oklahoma_k5]

My pictures of fab work are like the offroad pictures I've taken of my k5. i hate it when you are climbing a wall and and anything that falls off of the dash goes straight to the back seat. Still in the picture it looks like I'm driving down a gravel road. Kinda seems like the pictures make every thing bow and bend in a way they really are not.

I think I figured out the problem I was having with frame measuring square but still not being straight. I was cross measuring from the lower a arm bolt holes bringing in 10 or so inches of vertical measurement. At that point I had not acurately leveled the frame so i think the frame must of had a twist to it that was counter acting the sway in the measurements. Anyway it's straight now.

I do like the idea of gussets on the front upper mounts. They won't add much strength as the will be across the load placed on them not in line with it. But I have to cut the inner fender to clear the mount and gussets will make it flow better.
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[zeeman]

I have built Street Rods for 30 years plus and did alot of C-4 C-5 Corvette suspension. I think you would be way ahead using the stock corvette crossmember and modifying your frame to accept it and bolt it in like it was stock. It would be a whole lot less work and you would have all the factory mounts. Check out one I did in a 48 chevy on my web site. Hope this helps.
www.northwestdieseloffroad.com

[Oklahoma_k5]

If the upper a arm mount wouldn't have been bent I'd have looked at doing a front clip using the corvette subframe. Width of the front frame on the truck is not wide enough to put in the corvette sub frame without widening the frame rails or cutting the upper mounts off the corvette subframe and attaching it to the bottom of the frame.

I started this project in my mind 4 years ago planning on using a s10 frame. I read about and thought about it so many times when the c4 stuff came up on craigslist this became a new challenge to think about. Spent hours looking on the Internet for other c4 installs. Found a few but not many with more than one or two pictures. That's why I started posting here, trying to get some infomation out where others can find it. So if anyone has info, fling it out here for the rest of us.

Btw. Before looking at your website I never wanted a Cherokee with a diesel. Now I need to find a clean Cherokee. Thanks, I needed something else to work on.
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[zeeman]

Originally Posted by Oklahoma_k5

If the upper a arm mount wouldn't have been bent I'd have looked at doing a front clip using the corvette subframe. Width of the front frame on the truck is not wide enough to put in the corvette sub frame without widening the frame rails or cutting the upper mounts off the corvette subframe and attaching it to the bottom of the frame.

I started this project in my mind 4 years ago planning on using a s10 frame. I read about and thought about it so many times when the c4 stuff came up on craigslist this became a new challenge to think about. Spent hours looking on the Internet for other c4 installs. Found a few but not many with more than one or two pictures. That's why I started posting here, trying to get some infomation out where others can find it. So if anyone has info, fling it out here for the rest of us.

Btw. Before looking at your website I never wanted a Cherokee with a diesel. Now I need to find a clean Cherokee. Thanks, I needed something else to work on.
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One can never have enough projects!!

[Oklahoma_k5]

Not that it's finished but I needed to get some sheet metal on it to get some motivation back. I moved the front axle centerline forward in the frame one inch. It's a trade off between being centered in the wheel wells or the front of the truck looking like it has an overbite. If I did it again I probably wouldn't go the full inch but at this point I'm not moving it.
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[63 & 64 Bowties]

That was quick! I like the stance. I haven't seen an Old Navy truck for a long time. If I remember right, wasn't it several years ago they were selling them off? Have you had it that long?

[Chris.]

innovative solution!