'73 up drum to disc conversion track width change

S'cuder said
That's a good observation. In 1973 the parts manuals have different, new numbers for the drum brake steering knuckles. It's very possible the wheels were pushed out in a similar way as the disc brake equipped wheels. Looking at the OP's car, one notices the track difference, front to rear.

The 73+ drums used a redesigned B-body knuckle starting around November of ‘72 for the ‘73 model year, they used large upper ball joints and the larger 73+ wheel bearings too.

That said, I honestly don’t know for sure if the ‘73+ drums had the same track width as the ‘73+ disks. Based on what I’ve seen I think the 73+ drums have a wider track than the 67-72 drums. But I’m not sure if it’s actually the same as the disks.

Kern Dog said
No, not entirely true.
The B body axle had the spring mounts at 44” center to center. The A body is 43”. I’ve heard of dudes just spreading the leaf springs to mount a B axle but to me, that is a hack move for dudes that don’t have a welder.

Or better yet just move the perches to 42” and get a set of DoctorDiff 1/2” offset hangers/shackles. I mean, if you’re gonna move the perches why not right? Max out the tire clearance for the stock wheel tubs and run some more tire!

But yeah, the B-body 8 3/4’s are not just a “bolt in” operation either way. Leaving the perches at 44” and side loading the springs and losing tire clearance while you’re at it is shade tree hack job stuff.

DionR said
The NVMA specifications only list one front track width for a '74 as well.

[URL]https://www.hamtramck-historic...eManufacturersAssociation-10.shtml?load_img=4[/URL]

I like these specs, but I’m not entirely sure how accurate they are for different option groups. Like the ‘70 specs list the rear track at 55.6” and the ‘74 lists it at 55.4”, but the width difference between a 7.25, 8.25 and 8 3/4 is quite a bit more than that.