Spitting off the belts?

Valvebounce said
I ran a 340/418 stroker at the drags yesterday.
First run it spat the power steering belt, and turned the water pump belt inside out.
We left the power steer belt off for the day. (After all, that power steer pump is stealing horsepower)
But next run it spat the water pump belt right off. (Fortunately it stayed on the engine, I left a supercharger belt on the start line once lol)
So we raced off to a parts shop to get a new belt.
Third run the belt stayed on fine.
fourth run it spat it again.
All the pulleys are factory ones. The alignment looks pretty good. It anything, there could be that one real thin shim missing from behind the water pump pulley.

Could that be enough to make it throw belts?
It's not a big ask to make new crank and alt pulleys from scratch for it. (Have a fitter and turner at the ready)

I went through the same BS with my 7000RPM 408. I have found, the factory bracketry, likes to flex and wobble too much for my liking (or for belts to stay on for that matter)

the power steering pulleys are thin, and easy to bend/warp. i threw them constantly at high RPM. (until i dumped PS altogether)

i do still run an alternator on the car. once the alternator gets to spinning, it puts out a load on the belt. if it's not perfectly aligned, it walks also, and usually throws.

We sell a small, milodon crank pulley, to slow the alternator belt down, and prevent throwing of the belt. It's the "cheaper" fix, than buying an entire serp setup. Sounds like you're a machinist. Dunno if i'd fire up the lathe for $70.lol

http://paceperformance.com/i-842271...ft-pulley-moroso-performance-64700-mopar.html