rod length

[strykr]

A quick question. A guy I work with dad recently passed away. He was into modified racing big time. In his estate he had all kind of new and very little used parts. One of things he had was a set of pistons for a 383 stroker motor. Is there a good way to tell what rod these pistons used 5.7 or 6 inch. They are stamped with SRP 40 on the bottom. I e-mailed the people at SRP but have had no response. I tried to cross reference the numbers with the ones showed one the web-site but the numbers dont match up. Any help would be appreciated. Thanks.

[soonersublime]

Measure from the top of the wrist pin hole to the top of the piston. Then take a piston that you know is a 5.7 or a 6.0 and measure it. This will tell you right away what is what. Or you can mock it.

[bumpdrafter]

No motor guru here but if you can't measure and do the math to figure out what the compression height; if for a 5.7 rod the wrist pin hole should be below the oil ring groove if a 6.0" or longer rod the pin hole should be up into the oil ring groove. If you can accurately measure the piston the math is pretty simple to figure out the compression height which will tell you the rod and stroke for the pistons. Like I said not a motor guru but if I can do it anyone can.

[dirtrace09]

You can take them to a engine machine shop or engine builder. They can measure them very quickly if you are not comfortable doing it.

[parrot69777]

To figure compression height you measure from the top of the wrist pin hole to the top of the piston (flat part... not top of dome). Then you add that to half the wrist pin diameter. If they are 6" rod pistons....it would be somewhere between 1.120-1.125. 5.7 rod would be around 1.425.

For those who don't like doing math.....goto www.KB-silvolite.com or United Engine & Machine. They have all kinds of engine calculators. All you have to do is put in the info they ask and it calculates everything for you.

[strykr]

Thanks for all the help. I really do appreciate it.