Taking the plunge: LS3 into '64 Tempest. Need help with shopping list. by b-man

4 minute(s) of a 224 minute read

.....for those of you who may be contemplating a swap from stock rear drum brakes to Corvette disc brakes.

The thickness of the Z51 13" Corvette rotors where they attach to the axle flange is .275", the GM 9-1/2" brake drums are only .095" thick.

These rear disc brakes will move the rear wheels out by .180", nearly 3/16". Don't forget to use slightly longer lug studs if needed.

Those of you who are tucking super-wide wheels and tires on the back of your car should know this, sometimes there's very little room to spare. In my case the .180" added thickness is a plus, I was expecting about .125" which would have been fine.

I needed a little bit less wheel backspace and this will put my 6.57" backspace 18X9" wheels within about .020" of their ideal location, it's really hard to get it to work out much closer than this.

1-2-2009

.....today fitting the wheel adapters and front wheels to the Tempest and making sure they had clearance.

Also tried out the spare wheel & 245/45-18 tire on the front, it will have to take the place of one of the 245/40-18s if I ever suffer a flat front tire.

I bought this particular size for the spare because it's spec'd at 26.7" tall, very close to the same height as the 26.6" tall 275/40-18 rear tires, but narrow enough that I'll still be able to use it up front with little to no interference with the front wheelwells. Actual measuring showed the 275/40s and the 245/45s to be exactly the same height, right about 26.75" unloaded.

The reason I wanted the spare tire to be the same height as the rear tires is to avoid damaging the posi unit in the rear end. Running tires of differing diameters on the rear end will burn up most limited-slip rear ends if you have to drive any real distance with it that way.

Wheel adapter mounted, I had them made with a wheel-centric ring to locate the wheel as precisely as possible.



Point of slight interference, at the rear bottom corner of the front fender. On right turns, the right fender hits the tire here. Same deal on the other side when turn left. Pictures show the 245/40s, additional clearance will be needed for the spare 245/45 tire.





After a few whacks with a 2-pound hammer there's now enough room for the spare tire to have the clearance it needs to make turns. Even though the Tempest isn't sitting anywhere near its normal ride height right now this was a known point of interference with the old 17" wheel/tire combo. It needed some more attention due to the added diameter of the new 245/40-18s over the old 235/45-17s, not to mention the new taller spare.



The Tempest sits like a 4-wheel drive with no engine, trans or interior installed. I'll have to wait until the car goes together completely before I can figure out how much I'll need to trim the front coils.





Not much else going on right now until the trans and converter arrive in a couple of weeks, the new rear end and rear suspension parts have yet to arrive as well.

I still have to gather up all of the Vintage Air parts I need. There's a lot of things yet to do here in 2009 to get this car running.

Happy New Year all!