Racecar building

Looks like a lot of fun..I wish they had something closer to me like that..

depending on who you run with you may *not* be required to run one...  here's what the NASA CCR states (below).  I haven't figured out what I'm doing yet but I did by a tow STRAP instead of a hook. We'll see if I come up with a good place to attach it. You could put a tow point on the rollcage at the upper corner of the driver's front window.  we have one there on the chumpcar RX7.

Hey Matt. It's not just the rim width. Need to know what width TIRE you want to run. I assume you are running an AMC 20 rear? I have a Ford 9" in the racecar.

Do you have any wheel/tire you can put on to take measurements? What I've done to figure out backspacing is to put something on the car that I can eyeball and take measurements. You want to figure out how many inches you have from the inside of the tire to whatever the thing that the tire will hit first. Usually the leaf spring but you said you have the CF 4 link right? Then you measure from the outside of the tire to the edge of the wheel opening.

So let's say you have an inch both inside and outside and you want to increase the tire width 1" over the mock-up wheel/tire. Well that means your going to gain a half inch to both the inside and outside. In my example I said you had an inch both directions so that's fine. If you also want to move the tire in or out then you play with backspacing. So let's Change my example and say that you had 1" to the inside to play with and 2" to the outside. You want to grow the tire width 1" BUT you also want to push the tire to the outside to be flush with the wheel opening. Well the outside gets a half inch bigger because of the wider tire. If you then also decrease the backspacing by an inch and a half you now have the wheel flush with the wheel opening and you have 2" of room to the inside obstruction. Conversely increasing the backspacing will move the wheel to the inside of the car.

Hopefully that's not as much of a pain to read as it was to type on this tablet but if I lost you just give me a call and I'll see if I can do better talking you through it. I'll PM you my number.

Please post pics of your car. Sounds female caninein'!

great.  also, don't forget to think about DIAMETER of the tire as well... you can adjust by selecting the sidewall height you want.  ie, 275/40 vs 275/45...

GreggR wrote: I've made some glacial progress on the '75 Hornet... The air-shocks that the PO installed in the rear are history. KYB Gas units are stradling the one-legger 15. The old AMC axle will eventually get replaced by a SN95 Mustang 8.8... but that's down the road. The ADDCO 915 small-body rear bar went in today. Oddly, this install came up twice today in the Suspension section... I fitted the Bullitt 17x8's as well. I used 1" wheel spacers, which worked well. When I do the front-end/disc brake upgrade, the 1"-ers may need a redo... This is going to be a slow go... but I want to keep making progress... Thanks to everybody who has helped keep this thread active... love this site...

Race ? 8.8 won't hold HP . 20's are stronger and easy to swap . Look in drive line here .