I was wondering if anyone knew the distance between the tires on a 1986 or so RX7 rearend.

I want to build a +442 but I dont know if that will fit.
I found to donor cars for really cheap. I wanted to go a diffrent way but this will be great if it works.

I guess while i'm at it, how do they measure track width? Is it to the center of the tread or the inside of the tire?

That's measured between the centers of the tread.

Jim McS says on his site somewhere that maybe he should have made it a +3 rather than a +4, because there's very little room for the trailing arms.

56.7" less 46" for the chassis less 8.1" for half of two 205 tires equals 2.6", or 1.3" per side. Not a lot of room! Should be OK with rod ends on the trailing arms, though.

Thats not too bad. I'm sure i could build around it.

I found a 86 RX7 with a blown motor for $300, so it might be worth a look!

Thanks man.