machinist said he needs these pistons Speed Pro L2621F
Bore (in):3.897 in.
Bore (mm):98.984mm
Piston Style:Flat top, with two valve reliefs
Piston Material:Forged aluminum
Compression Distance (in):1.338 in.
Piston Head Volume (cc):+5.00cc
Pin Diameter (in):0.945 in.
Rod length 6.098

For my 5.3 build, any idea where i could get some that are a different brand, as that brand discontinued the piston, will i have to go custom? or... any info is greatly appreciated. im emailing some of the piston makers to see the cost, any idea what company might custom make them for a reasonable price?

 

What rods are you using? Is the block already bored and honed?

 

Diamond

 

Using stock lm7 rods, oh and I'll check out diamond. Yes bored and honed, just waiting for pistons

 

For future reference, you really want to have the pistons in hand before honing the block or else you get stuck in a predicament like this.

If the cylinders are really at 3.897", you're going to have a hard time finding shelf pistons. You could easily find something at 3.905" as that is a common bore size. You can probably find a hypereutectic piston that will work though.

You probably need your machinist to get involved selecting pistons for you since the block is already machined and he knows what the critical dimensions are.