I heard just a couple weeks ago (from a builder)that when you order a 383 rotating assembly that the #7 piston will be a slightly different size than the rest of the pistons. Has anyone else ever heard of this? I had not, but the guy swore to me that he has read horror stories of where people have not put the correct piston in the #7 cylinder.

Is this just a myth or has anyone else ever heard of this?

 

I don't know about other kits but with the Lunati kit, that is not the case.
They are all the same size.

 

yeah and you need a left hand screw driver to replace that muffler bearing

 

You may also be a little low on headlight fluid....

but seriously I have never heard of that.

 

Im not sure who you are talking to, but that is not true. If you are looking for a rotating assembly shoot me a PM.

Thanks,
Leo

 

Thanks for the replies, and the sarcasm LOL. I will have to get the guy who told me that to post on here and explain why he thinks one piston is different.

Edit: He said its the #8 piston, not the #7, and only with certain aftermarket crankshafts and 383 kits.

 

Well, after talking to Jon at TSP, he tells me that this guy is actually correct about one piston being slightly different for 383 stroker kits. One piston will be slightly notched in the back and that one is intended to go in the #8 spot. The notch is there for clearance where the piston will come close to the reluctor wheel due to the longer stroke.

Now, my question is: If one piston has a notch cut out, then the weight of it will be just the slightest bit different than the other 7. How can the rotating assembly be balanced if all pistons aren't the exact same weight?

Any thoughts on this now?

 

Ok well maybe on some brand of pistons this may be true. On the Wiseco's and Mahles that we use to assemble engines in house we have never had a notch to deal with on the piston. We have also never had an issue with clearances between the piston and the reluctor wheel.

 

It is true of Diamond pistons as well, and it only applies to those going on a 4" stroke or greater. I know when I put my 408 together, I forgot to put the right one in the #7 hole and the motor wouldn't turn over by hand. Figured it out and swapped with no issues.

 

Mine are diamond pistons. So is it the #7 or the #8? I am hearing two different stories.

 

Whichever one is the rearmost. I guess it's actually 8.

 

Ok, thanks for your help.

 

Yeah if you just look at the piston, you'll see it. I just forgot about it.