I recently received a set of 8 327" SBC pistons, as the owner had no use for 327 pistons and go tired of them setting around his shop for "years".

Well they turned out to be 350 pistons, cast aluminum, with a pop up measured at .175" and very deep valve reliefs. The only identifing marks I can find are a stamped .030 (30 over), four stamped R, and four stamped L. The cast letters on the back side of the skirts "LIFELINE".

My real qusetion is; how do I determine the piston top displacement in cc's? These pistons appear to be very old.

Thanks, Andy

 

How do you know they're 350 pistons? The only diff between a 327 piston and a 350 piston would be compression height. 1.56" compared to 1.675"

And the only true way to measure them is in a block attached to a rod and the crank that's going to be used. You have to measure them as if they're flat tops, minus the difference that the volume of the dome takes up.

 

Using the methods you have mentioned, they have been determined to be 350 pistons.

 

One simple way, would be to use a beaker or something, with graduated markings on the sides; fill it to some convenient mark; lower a piston into it; see where the fluid level goes to.

Another way would be to get some graph paper with 1" or 1cm grid lines, preferably divided down to .1" or 1mm; lay it over the dome, trace the dome on the paper, and count the squares, then multiply by the dome height.

This is not rocket science here, it's just car parts.

 

I thought of using the beaker method, but air will become trapped in the valve reliefs.

I realize it's "not rocket science", but I thought that knowing the compression ratio might be helpful to me later.

 

Then measure the valve relief volume with a head cc'ing buret or a syringe or a pipette.

Don't try to outsmart yourself.

 

Thank you