[classic_chevy_guy]

i have a 70 chevelle that is, hopefully soon, gonna support an all aluminum 427 like the corvettes. Im puttin a 6-71 on top of that and so it should be puttin out around 600-650 hp/550-600 lb-ft, i hope. I dont need a whole lot more power than that since its mostly gonna be driven around on the street, and i'll probably have to underwork it because i want it to be a performance vehicle for the street and road course. I know the chevelles are like one of the heaviest things out there, but i still wanna try, cause i think it would really drop some jaws seein that car on the course pullin some great numbers. But to the point. Along with the 427 i was thinkin about puttin in a T56, which those are rated at about 550 lb-ft, and im not sure about the Corvette IRS. I hear a lot of good things about em like traction and stuff, but i also hear that their weak, not made for heavy vehicles, expensive, and have to be worked on 24-7. Can anybody help me, cause im lost and I really need to know if the IRS is a good idea for what i want before i go to spendin.

[crossfire84]

you would want to use the 1968 thru 78 IRS these were all big block bilt. these were used on the L88 vette these were reported to make anywhere from 560- 600 hp+.GM would test these at there proving grounds by doing neutral drops 4000 rpm, they were also testing the turbo 400 this way, if it could live like this i don't see any problem here. I had a 78 i put a warmed over 440 BBC in it with a Richmond 5 spd, a lot of fun. the only problem i see is you mite have to widen the half shafts , also don't forget the rear spring has a high arch to it, sounds like floor pan mods maybe. how are you hooking up the trailing arms? this is a lot of work, you could look into grafting on a rear frame from a vette this mite be the best way. all-so one last thing all the vipers use the Dana 44 rear end same as the vette, hope this helps.

[shawne]

i have been speaking with don mcneill at flat out engineering in orange, CA. he specializes is corvette irs kits for dirrerent applications, he is sending me a kit for my 51 chevy pickup. i don't have the number handy, they do not have a website yet, but their info will come up on a google search. hope that helps.

[427v8]

A decent vette IRS with goos u-joints will take 750hp

U-joints are the weak spot.

Also watch your camber, too much camber change as you launch will ruin your traction

[classic_chevy_guy]

alright well ive done a pretty good bit of lookin around at all the different types and styles of IRS. I havent completely decided yet, and i was wounderin if anybody could help me out on another question i have. I looked at the Corvette IRS from progressive automotive and the IRS from kugel komponents. Both are aluminum, and the only difference between the two is that the Corvettes put brakes on the hubs, whereas Kugel makes one with the brakes located right at the output shafts. does anybody know which would be the better selection, or would either do just as good for street applications???

thanks,
classic