Does anyone have any experience in addition to opinion on the durability of a GM ZZ4 shortblock.

This is a road race application only. No street time ever.

How well will the bottom end hold up RPM wise?

I have heard that the hyperturopic pistons are fine as long as you to not expose them to detonation. They crack but do not melt or fly apart.

My plan of action is to add my Champ oil pan, 195 AFR heads, Vic Jr, 750 dp and solid roller from my expired engine.

The expired engine had JE flat tops, 6 inch eagle rods, GM steel crank. I have not yet preformed a post mortum, but believe a rod let go.

I plan to pull engine this weekend.

 

ttt

 

i believe the zz4 had forged internals(rods/crank)/4 bolt mains etc.... i would say that the pistons are gona be your weak spot, then the rods, i wouldnt worry bout the crank/or the caps. id say if its fitted wit ARP that this thing will rev to 6500-7000. u gotta be careful with hypo pistons, there strong but they can go. alot better than cast, but not as strong as forged.... forged have there downfalls too tho... like i heard there is more play with forged bc of how that heat up and wear at the block/ not to mention there weight, etc... hyper pistons are better for the street i believe if u dont throw alot of boost or the giggle juice

 

The rods are PM.

I'd keep it below 6500.

If a rod let go in your current engine, there probably isn't much left of the cam, either.

 

I tore engine down over the weekend.

Lost two rods. Looks like the bolt broke although it may have broken after the fact.
57 Kid I think you are correct about the cam. I cant get it out of the block.

I believe the cam is bent or either the block has shifter and has the cam bearing out of square.

Good new is heads are ok, lifter are ok, valve train except for cam appears to be fine.