8-lug brake upgrades?

[Steve@OldSub.com]

I'm using the IFS from a '72 C20 under a '54 GMC 1-ton project. The '72 has 12.5 inch disk and the C20 and C30 part numbers for brakes are all the same so I'm comfortable this stuff is up to the job.

But never being completely satisfied I looked at the parts available for an '87 and discovered the rotors are 12.875, fully 3/8ths larger in diameter.

So I have two questions: First does anyone think that 3/8ths inch would make a real difference? Second how easy is it to upgrade my '72 IFS to the later larger brakes?

And a third question, is there some other 8-lug brake upgrade that makes sense? I don't mind going out and finding a later IFS crossmember is that is the right way to approach this. I doubt it would cost even $100 to find a later one and I'd rather upgrade before I start spending money rebuilding the early IFS.

But if there isn't really any difference I'd rather stick with what I have and keep building rather than look for more parts and more work.

Thoughts?

[Steve@OldSub.com]

Any input on 8-lug disk brakes?

[panhandler62]

I don't really have an answer for you there. I have a 68. I got the whole front end (minus the actual cross member) out of an 87. I am just getting to the initial stages on the front end now.

I don't think 3/8" diameter on the rotors will make much difference. 3/8" thickness would be a lot though.

Except for a set of drop spindles and trimmed springs; I will be using the 87 components (with consumables like tie rod ends, bushings and ball joints replaced) as is. I rehabbed the arms and will be doing the same for the sway bar. The rotors look like poo. If they don't clean up well I will replace them.

I don't *think* there are any fitment issues from 72 to 87, but with all the grinder and vise time I have put in to date; I don't count anything as a sure bet till someone details having done it.

[Steve@OldSub.com]

Thanks Keith. I may need to do some more research in the parts books. If I'm replacing rotors and calipers anyway and its easy to do with the '72 spindles I'll probably upgrade. If its hard....