wgbsigns

just finished painting my vette yesterday! new rims came in this past thurs (intro pentia) 18x12 and 18x9. now the question is i ned to lower the rear about 4". i got fiberglass spring and 8" bolts to install at rear. heard you guys talk about raising the rear center section up in the car to prevent half shafts from going past level during scwating of rear when cornering or upon launch. if this is nessesary, i was going to knotch the crossmember. box it in and add a plate to the top, redrill for rearend position. this should raise the rear about half the thickness of the crossmember. then lower the rest of what is needed with the spring bolts. is this how it is done or is there a better way? what do i do at the pinion, shim it??? or will the spring and bolts give me 4" without cuting the crossmember? spring is 360# bolts are 8" car is now big block and it is a t-top car if that matters. any advise would be helpful. thanks, greg
will post pics soon as i get the car buffed out and get it lowered. looks like a 4x4 right now.

TheSkunkWorks

You can raise the diff cross-member about an inch in the frame by doing away with the rubber mounts and tabs, and welding in some mounting plates. If you still want to maintain some isolation from gear noise, another member came up with an interesting idea that still yields about 3/4" higher diff.

This thread includes a post with dimensions for the solid plates... http://forums.corvetteforum.com/show....php?t=1601099

This thread includes info on a poly bushed raised diff x-member installation... http://forums.corvetteforum.com/show....php?t=1774542

BTW, Tom's Diff's has a diff cross-member mount reinforcing kit you might want to look at, while you're at it... http://www.tomsdifferentials.com/catalog.asp?pg=26

enkeivette

My guess is that the half shafts will be parallel to the ground with the 8" bolts. It wasn't until I installed the 10" bolts with my 360lb spring that my halfshafts angled up.

wgbsigns

maybe i will need 10" bolts? rear has to be lowered 4" to 4.5" no less to look right. will the 8s do it or should i go on and get the 10s?

wgbsigns

thanks for the links,

TheSkunkWorks

torqvette, you probably know you're running the risk of binding (and breaking) those U's when your car squats, putting the diff even lower, which obviously makes you a good candidate for raising the diff. I believe it's recommended not to to exceed about 5* angle...

wgbsigns, to go that far (BTW, depending on your current height, that's most likely far lower than optimum high-perf settings, just so you're aware) you should try the 10's first. ...and, you're welcome.

WashingtonRacer

have you drove the car since installing the spring? initally they sit rather high. Mine did the same thing. I pulled it off back off redid it again, dropped it all the way down, Still it sat high. So i finally took it for a 2 mile drive, and when i stopped it was hugging the ground.

chris75stingray

i can't picture the back sitting 4" up with 18" rims and 8" bolts .are you sure everything is settled down?

wgbsigns

no its all stock at this moment, rearend wise. just painted it, put wheels on. still have to install spring and bolts. i just wanted to know what it took to lower what i need and how to do it right the first time to get the best performance possable.
so car is stock hight now with a good factory spring. so it sat a little high to me with stock wheels and a 27" tall tire in back.(meaning the gap between tire and fender) now with fender flares and a 25.9" tire it has the 4x4 look. i could live with 3.5" lower in rear if that would make for better handeling. thanks, greg