360 bore, is piston match a necessity?

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Mopar204

Mopar204

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I have an engine block I just bought, from a very reliable guy in the mopar community where I live. Long story short, the block is bored and decked, cleared for a 4" stoker kit. I bought a 408 striker kit. Then I was told I needed to get my pistons bored with the cylinders. How essential is that to be done? Is there measuring I could do to see if I could avoid spending more time and money getting my pistons and rings matched to my cylinder bore? This engine isn't gonna be more than 450hp steet car
 
In a perfect world yes. Match piston to bore. In the real world? You can get away with not doing it. Now watch 24 people will chime in and tell you 24 different things. Throw up 17 disagree flags & change the topic to what cylinder heads you should run. Let the games begin. Keep your build simple and easy. Good luck. :rolleyes:
 
Well...the reason the machine shop wants the piston is to ensure you have the correct clearance...as forged...cast and hyper piston and even different manufacturers tell you what piston wall clearance to use...

if they are boring the block there is no extra cost or time involved...plus the machine shop needs to know what kind of rings you are using so they can hone the cylinder wall to the correct finish for the rings....
 
I'm sure there wouldn't be an issue with it being matched to my pistons and rings if I(myself) was the one that got it bored. But the fact that it has already been bored before me getting it doesn't help. I think I'll keep in mind the clearances the kit tells me they want and if I'm out of range maybe I'll get a machine shop to match them together.
 
Has the engine already been final honed? Check to make sure you have the proper piston skirt clearance. If you are within spec for the pistons You are using then You won't have to resize. If you are tight you will be asking for trouble. If you are loose you are asking for trouble. chevk with your piston manufactirer. KB pistons and cast pistons like to be tighter than forged pistons. Forged pistons grow with heat so you jave to typically set them up with more clearance. After all that You should make sure you have the correct finish for the rings you are using. Molly rings require different finish than standard cast rings. This is why the machinest wants your pistons when he is finish honing the cylinders.
 
Oh and if your ring gaps are too tight they will break rings. Always Always check to make sure the parts you install are fit to specs. All Parts
 
Maybe it is a good idea to send the pistons with the block. Sounds like I'd better be safe than sorry. It has yet to be honed and the pistons are forged. Not sure on the rings though
 
Yes, for sure. If you bore for hyper piston clearances and put in forged pistons, then the pistons will scuff (damaged and ruined). If you bore for forged pistons and put in hypers, then they will rattle (and have poor ring seal). These problems will show up even on a 1 HP street engine.

Giving the pistons to the shop is like Machine Work 101.... help them do it correctly. There are some things you can skip for a lower performance engine but this is not one of them.
 
Stick a piston in the bore about 2" from the deck and see how big a feeler gage you can get between the piston skirt and cylinder wall. Most use moly rings, I'm betting the finish is right but the clearance is a mystery, most likely near .002...but you need to verify the above.
 
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