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Home Blog Blog interest in rear end swap?

interest in rear end swap?

Home Page Forums Discussion Topics – Ask the Experts interest in rear end swap?

This topic contains 9 replies, has 4 voices, and was last updated by  mini88 3 years, 4 months ago.

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    im wanting to gauge interest in a possible rear end swap for our cars. idk what rear end it will be but im thinking of offering a weld on kit where you get the rear end you want and the kit will come with brackets that you weld on the rear end and control arms to bolt in factory locations on car. alternatively If i can find a rear end thats easy to obtain and make fit i could sell the rear end with brackets already welded on and ready to bolt in. the idea of this is to have a stronger rear end for our cars with more gearing option, posi’s and just the general availability to rebuild them



    also vurious as to what would be more popular, retaining for lug or going to five lug. also disk vs drums, obviously if you dont convert to front disk you will be wanting to have a drum rear. voice your opinions and let me know what you would like to see in a rear end swap.



    I meant to say “also curious”



    Although I don’t think I need a rear end swap at this time, car isn’t on the road yet and the internals look good, I keep hearing how weak they are with lack of parts. Friend and I each have 62’s, cutlass and a Jetfire, and the shop is restoring another jetfire so availability of a good common rear end that would be a turn key bolt-in sounds like a good idea to me. I would go for a drum rear and 5 lug to keep costs down and wheel options up since 5 lug front disc brake kits are available. GM 10 bolt sounds like a good one to me.



    If you were to do this I would use the 8.5 10 bolt. Easy to find and to get parts for. I am not sure how wide they are compared to the 62 rear end?



    i would only use the 8.5 in something with an engine swap, i have one in my 62 back halved 455 cutlass. its way more rear end than these cars need and will need to be narrowed. a 7.5 will be plenty strong for the probably all of us running 215’s and s10 rear ends may not need to be narrowed at all which will keep cost down. i could do an 8.5 for someone but the extra cost of narrowing it will be factored in. you can by gears posi’s axles etc for the 7.5 and even in stock form will be a dramatic improvement. thanks for replying, i would like to bring a few swaps to the market to help keep us on the road as i really enjoy these cars and want others too as well. other things im hoping to bring available will be an auto swap for people who want auto’s, i have not done any testing or anything yet, and possibly headers



    when my cutlass project was supposed to be a street car i had originaly narrowed my 8.5 about 10 inches. the upper mounting point was higher on the new rear end vs old so i had to raise the mounting point on the frame. it all worked but the project evolved and is now back halved and the rear end was narrowed about another 4″ for a wider wheel



    I’ve swapped a “G” body (1978-1988 Cutlass) rear into my Jetfire to gain the 5 lug wheels and daily driver reliability. I cut the lower control arm/shock brackets off of the original, welded them in place and used 1988 GMC 1/2 ton (air)shocks. I fabricated new, adjustable upper control arms due to a slight angle change and retained the original lower arms. From what I read somewhere, the driveshaft/pinion was set pretty low on the original rears to clear the minimal tunnel area on these cars which were supposedly built on the Corvair platform. Consequently, the air shocks come in handy to keep the driveshaft from hitting the tunnel in the rear. When I put the mustang II suspension up front, I used the original Jetfire front springs in the rear. Being that I went with the newer 2004r overdrive trans, I modified a 1980’s driveshaft to hook everything up and it works well as long as I keep some air in those shocks. I also slightly dropped the trans mounting which also helped the driveshaft clearance but it still is an issue. I wanted my car to look like a 442 would’ve looked like in ’63 so I used the 15 x 7″ factory rally wheels which are too wide with the “g” rear so you’d either have to find wheels with a different offset or modify the wheel well lip. I agree that an 8.5 rear (GN) would be plenty of beef for such a light car.



    Did you have to mod the tranny tunnel for the 200r4? And did you keep the 215?



    Yes I did have to modify the trans tunnel to accommodate the HEI and the trans clearance demands. When I got the car it had a cast iron ’65 Buick 300 which didn’t run and someone had put a turbo 350 trans in it. I pulled both and put a roller cam Olds 307 with the stainless tubular exhaust manifolds which I knew I’d have to modify to clear the steering which is the biggest obstacle to putting an Olds V8 in these cars. A double diaphragm Corvette power brake booster squeezes in there fairly well but not with a big block Rocket, only a small block. I wouldn’t have done the mods if it was a practical restoration to original but it wasn’t. Being a heater delete car from Hawaii, the clean firewall made things easier and I was able to fabricate a heater/defroster like the old cars had under the dash. The 80’s Camaro shifter works well with the 2004r.

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