My new sbc uses a 6 1/4” balancer. I have a crank trigger set up from another sbc, but from a 8” balancer. I’ve bolted it together and see no reason it won’t work. The trigger wheel is a good bit larger than the balancer but looks like it will work. Has anyone else done this or can anyone give me a reason it won’t work? I would rather not buy another crank trigger set if I don’t have to.

A circle has 360°. It doesn't care what the diameter is.

Roger that is my reasonings too. Just got to thinking about it, since they sell crank trigger kits for different diameter balancer.

You'll be fine.

Best bet is to have a friend with a lathe! I've made spacers of various thicknesses for friends.

Spacing for trigger PU ,pulleys, belts is most important thing.

Bigger diameter is technically more accurate being the trigger points are further apart. But after 5-6 inches it's light years better than the 1-2 inches of a distributor already, so it's not a measurable gain.

All that matters is you have the bolt on bracket and pick-up to match whatever diameter wheel you're using. I think everything is flying magnet now days....

Mine has been that way to years, no worries.

I think I have a BB Chev on an Oldsmobile--works fine bur 1/2 bigger.

The only concern is that the wheel locates properly on the balancer so that it is centered. Some balancers have a lip that is different depending on the size of the balancer and that is why there are different wheels. As long as it is centered when installed, the diameter doesn't matter.