When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
Getting ready to put a Quick Performance 9" into my son's 88gta. It's a gen 1 sb/th400 with a 9 bolt. We bought the car as, so don't know if the drive shaft is stock length or not. Anyone done a 9" swap know if we will need to shorten or build a longer drive shaft? Also, Quick is recommending 1/2"x3" studs as this is a drag race only car. Will these studs work with the stock snowflake wheels? Thanks
Stud size is dependent on hp,slips, and weight most of all. I would rather change wheels and suit a big stud and not worry about it then have studs break. Seen it before and it's not pretty.
your same driveline should be able to be used. I would always measure the forward yoke and make sure it is in the tail housing far enough. As well as needing the correct u joint for what you are running for a rear yoke.
Driveshaft length will probably fit but it may be off slightly. All depends on what yoke is used on the diff.
As for wheel studs, the tiny 7/16 and 12mm studs are good for street use. It doesn't hurt to upgrade to 1/2" studs. The factory rims will still fit over 1/2" studs. All you'll need is some 1/2" wheel nuts.
I'm at the power level where I need 5/8" wheel studs which use wheel nut spacers and flanged wheel nuts. My front tires use 1/2".
I've seen 7/16" and 1/2" wheel studs snap on the starting line.
Thanks for the replies. We have a fairly mild 327 with a stock convertor. The posi in the 9 bolt was wearing out and the 2.70 gears weren't good for drag racing. Going 9 inch instead of trying to upgrade the 9 bolt. I figure if we need to alter the driveshaft I'll have the driveline shop change the rear yoke over to a 1350 so we don't need a conversion u joint.
One more question, what are you guys using for brake lines? We are using the QP disc brake kit. Did you use their kit or are there oem hoses that will work?
I use junkyard rear disk brakes (see my sticky in the brakes forum for disk brakes on any diff). I use aftermarket steel braided lines to banjo fittings on the calipers.
First off what yke are you using on the rear? I wouldn't use anything but a 1350 size joint on the shaft, do it once and move on. Drag only I'd use 5/8" studs again do it once and be done. The 1/2 studs most likely won't fit in stock wheels. Very few people ever want to make their car slower once they start racing.
Im installing a QP 9" in the next few weeks and I went with the 5/8x2" studs. I have a nice 3.5" aluminum DS in there now but i think i should go to a steel 3" min if i plan to almost dump the clutch off the line.
get rid of the aluminum shaft. my friend broke the one in his 98 camaro. set off the airbags, busted out the windshield, and beat up the underside of the car. it was a bolton car with a 100 shot and t56/9"/slicks.
oh yea, and i ran 1/2" studs down to a 1.30 60'. you need to torque them down correctly and use the correct lug nuts with no spacers.
Aftermarket aluminum shafts are a bit stronger than an OEM aluminum shaft but neither are stronger than a good 3" steel shaft. I had one custom made for my car. 3" x 0.083" wall steel tube with 1350 ends. Very hard transbrake launches and the driveshaft still survives.
I went with Moser for my 9" housing but used QP for the third member. They're great to work with and set up my gears perfectly.
When I switched over to TKO 600 trans I had my drive shaft re-tubed 1" longer. When I switch my 9 bolt over to the 9" I reused the same drive shaft and it was perfect length. I used the smaller yoke (1330 I think) and my original u-joint too. It's probably best to mock it all up and measure but you'll probably be ok length wise. It really depends on the trans length, yoke lengths and the position of the trans and rear. I have lower control arm relocation brackets and when the control arm is in the lower hole, the yoke can walk fore/aft about an inch depending on torque arm adjustment. I'd get everything adjusted close to where it needs to be prior to measuring.
For brakes I re-used my 9" PBR calipers. I had the rear end setup for 98+ LS1 style brakes and made my own rear brackets. All my stock metal and rubber lines worked with a bit of re-bending of the cross tube line and welding a mount for the Tee. E-brake cables mounted up like stock.
I have an adjustable torque arm I made years ago and it needed a bit of modification to fit the Moser adaptor. Since the QP torque arm mounts differently you'll have different clearances to consider. I'm still using a trans mounted front TQ arm mount too so it depends on the front mount as well. The 9" yoke is moved over about an inch toward the passengers side which required a bit of massaging of my 3 1/2 OD exhaust pipe. Overall its a great mod and I haven't noticed any loss of power (times) or harshness of ride. It did add about 75# of weight.
Last edited by antman89iroc; 01-28-2018 at 05:57 PM.
Your wheels might fit a 1/2" stud but that's a cone style lug nut and an aluminum wheel riding on the stud. Drag wheels have shoulder style lugs where the wheel rides on the shoulder of the lug nut so the wheel doesn't contact the stud.
Did any of you guys go with the fabricated housing QP offers? or just the stamped housing? Curious if the fabricated housing has any clearance issues over the stamped. I will be running the UMI watts link also. I am about to purchase a rear setup and trying to make the final decision and pull the trigger..
Fabricated housing are stronger and save a little bit of weight but are much more expensive. Nothing wrong with either one of them. How much of a budget do you have?
Fabricated housing are stronger and save a little bit of weight but are much more expensive. Nothing wrong with either one of them. How much of a budget do you have?
With talking to quick performance it was only $100 more. Budget isn't as big a concern as getting what I need/want for autocross and track. QP is just shy of 3k for the setup I have quoted right now.
Your wheels might fit a 1/2" stud but that's a cone style lug nut and an aluminum wheel riding on the stud.
With 60 degree acorn nuts, the stud is not in contact with the wheel. The wheel is riding on the hub and the taper on the nuts keep the PCD on the wheel concentric with the studs in the axle. Not sure what you're talking about.
Decided to go with the QP braided stainless brake hose kit. Does anyone have a pic of where you mounted the tab for the tee fitting? I read AlkyIROC's thread. The parts he used/made are very similar to what QP uses.
01-07-2018, 10:47 PM
