C5 chassis tucked under a '70 body

I know this has been discussed before and most of you even participated in those discussions. My engineering mind is always working on some crazy idea and this is my current one. Getting the wheel base and track are the most obvious problems because they would affect the overall look of the car.

The wheel base and track of the c3 vs c5 and c6

C3
Wheelbase: 98"
Track: 58.7" F, 59.4" R

C5
Wheelbase: 104.5"
Track: 62.1" F, 62" R

C6
Wheelbase: 105.7"
Track: 62.1" F, 60.7" R


I might be missing something, but to me these numbers seem very close. The c5 would be a better fit due to pricing/availability, but id love to have an LS2-3. The wheel base could be changed by chopping a few inches out of the center and the transaxle could be modified. The increased track wouldnt be a problem either. 3.4" in the front can be made up with flares or some custom work and the rear would easily fit under flares and you could still go wider.

The major issues i can think of would be the width of the outter frame rails on the new chassis. There isnt much room outboard of the c3 rails, if the c5-6 is wider that would take some serious work to move inboard. It could be rough working out a fuel cell around the transaxle without using dual tanks and pumps.

I have seen low mile c5-Z frames which included all suspension, all brakes, engine, manual tranny, computers (including ABS), and steering go for $11-12K. That is cheaper than the SRII chassis plus you get an engine and tranny for free. Once you sell the old tires/wheels, brakes, shocks, etc. It is probably in the stage 1 price range, but again, with an engine and tranny already there. Add pfadt coilovers, bigger brakes, mess with the engine, lots of home fabrication and ive got a rolling chassis, engine, tranny combo for under $20k (if i go ALL out on the suspension and brakes. A good setup could be under $15k). If i went with a SRII stage 2 plus a LS engine and T-56 im at at least $20 depending on how good a deal you can find on the engine/tranny.

Labor doesnt scare me, its part of the draw. Opinions??? I dont want to hear it cant be done. I want to hear WHY it cant be done. Once we know the hurdles its only a matter of time before they are overcome. :beer:

:huh: :twitch:

The biggest obstacle is fitting the rear diff & trans in the back with the stock wheelbase and be able to get some seats in there. The rear double a arms won't be much of a problem IMO, just cut out the storage compartment. The track width, remember that for C5 & 6 it's using pos. offset wheels, so if you want a deep negative offset look you have to count a couple of inches to the total and use some flares to tuck it all in.

The basic problem with a C5/6 drivetrain under a C3 is the transaxle. It's huge! The front of it intrudes in between the seats of a C3. Look at the Philly Motorsports site. They widened the car (take a look at how wide the console is). They also moved the wheel openings back (you probably won't find a side view of the car). Even at that the transaxle still could not be packaged well:



So you can buy a C3 roller for 12K but you don't have a frame. If you removed the stuff that you can't use from a C3 frame you would end up with the siderails and little more.

The SRIII frame or the one that Kid Vette posted a couple of days ago look like a better way to go. Neither use the C5/6 transaxle.

Looks like TT and I just posted the same info except for his point about track width. The published track width is not the outside of tire to outside of tire, it is center to center. So big tires and pos offset (for the C5/6) make it appear that the width of the cars are similar.

That's exactly what I mean, they measure to half width of the rim, but that means that for the C5/6 that's inboard of the brake hub because of the positive offset wheel, for the C3 it's about level with the hub. This means that if you use negative offset wheels you have to consider it will have a wider actual track width. INO a flared car with positive offset wheels look out of place (pos. offset wheels on C3s in general, there are only a few examples where I think it looks good)

Moving the rear suspension backwards is not that big an issue, I did it too. If you add flares there's a good 1.5" -2" you can play with right there so the flare lines up nice. In stock form the flares don't fit well at all, they make the wheel sit forward in the wheel arch.

Lets ignore the ascetic ramifications and pretend i add 6.5" to the rear section of the car. This would move the seats 6.5" forward in relation to the transaxle (keeping them the same distance from the front axle). If philly MS didnt do this, it looks like the seats would now clear the transaxle.

I agree with you that a c3 needs a negative offset wheel. I love the deep offset look. Off the shelf flares would get me 4". The published width of a c5 is 73.6 Inches and a 1970 is 69. IMO 4 inches would get the tires in the fenders, but I might need a little more flare or possibly bulge the fenders in addition to flares in order to get more of an offset.

Thanks for entertaining my pie in the sky ideas. Any other thoughts?

Anything is possible with enough determination and you are willing to make the mods that will be needed.It comes down to knowing what you are willing to change.Stretch the C-3 body?,shorten the chassis.The C-5/c-6 front is an easy swap,Is the transaxle a must?A C-4 dana 44 would not require the mods to the body and chasis and although it has been done alot,it works very well.
(It will also knock off a few pounds from your car!)Still if your set on the Transaxle, I think it can be done but will be hard to hide.:thumbs:It's a glass car and the body can be manipulated very easy.A few inches will not get noticed.(For most)6.5 will be quite a stretch but if you can make it look in proportion still and flow nice it will be COOL! I considered this at one time too,but it was out of my price range and the C-5s were still too new to come by.

Again this is all just my brain running crazy, no actual plans at this time.

I think the best solution would be to widen the entire car. Basically cut it in half and widen it several inches (4-6"). It would be a lot of work, but I have always felt the c3 looked too narrow. This would do 2 things, 1) it would help fit everything inside the fenders and 2) would spread the seats around the transaxle. I would move the rear wheel well back 1-2" and shorten the transaxle. The profile of the c3 is too nice to mess with too much. I feel a few inches wouldnt be noticable and only those who know corvettes would notice the door-wheel gap is larger than 2".

BBShark: Do you have more pictures of that car? I can only find the PDF artical and the one you posted. Thanks.

Double_take said:

Again this is all just my brain running crazy, no actual plans at this time.

I think the best solution would be to widen the entire car. Basically cut it in half and widen it several inches (4-6"). It would be a lot of work, but I have always felt the c3 looked too narrow. This would do 2 things, 1) it would help fit everything inside the fenders and 2) would spread the seats around the transaxle. I would move the rear wheel well back 1-2" and shorten the transaxle. The profile of the c3 is too nice to mess with too much. I feel a few inches wouldnt be noticable and only those who know corvettes would notice the door-wheel gap is larger than 2".

BBShark: Do you have more pictures of that car? I can only find the PDF artical and the one you posted. Thanks.

Click to expand...

I think the Philly MS car was widened at the rear as you describe. Sorry, I don't have any more pictures of it.

I am trying to get some info on the C3/5 frame that Kid Vette posted but not having much success contacting them. Either they are too busy making frames or too lazy to answer their email:confused2:

I just emailed them also. If I get any pics in response I will post them.

Ive been thinking more and more about widening the car. The hardest part to fab up IMO would be the front and rear window frame and trim. Some poly windows would solve the glass issue. Two sets of old cheap front and rear bumpers could be used to add the extra width and could then be rechromed. The body is just glass work which doesnt scare me at all. The hood could be difficult, especially if a L-88 hood is used.

No doubt it would be a monumental project, but if done correctly it could be one really bad ass vette.