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There's the best picture I could get of the clearance. We got the rings gapped and got the first rod and pistons in, haven't torqued the rod bolts down yet, just by hand with a socket. It's really really close in my opinion, but then again this is the first stroker I've ever put together. Setup is a 4" Lunati crank, 6.125" Lunati H-beam rods with ARP2000 bolts, and a Weisco +5cc dome aluminium piston. Main caps are torqued and degreed in the picture so the crank is in place properly. Block already bored and decked by the machine shop.
Thoughts? It's only pretty close on this side, but it's still making me worry a little...
Mark it and clearance with a hand carbide. Nothing bad will come from grinding in clearance here, but a lot of bad will come from the bolts hitting the block from flex and thermal expansion. I generally go a little over board here and give about .100" - .125" radial clearance. It will move a little less forward and aft. Just make sure that there are no burrs on the inside of the cylinder to scrape on the piston as it moves.
Last edited by Crf450r420; Oct 29, 2017 at 10:33 PM.
Tried to find a good stock block clearance in my pictures, but just have a sort of shot on my motor. Also have an RHS motor done much more to at least show you to not really fear doing what is needed.
Thanks everyone for the pictures and advice! The machine shop didn't listen to me because I had seen guys need to clearance LS2 blocks for a 400+ stroker. Gonna have a nice little chat with the owner tomorrow to see what he can do for me since he had my block for almost a week longer than he was supposed to. Either that or a local friend of mine said he'd come and help me in trade for moonshine lol
He's going to be there for guidance, he's built a ton of LS motors for the speed shop he works at. Since this is my first time and my GTO is my baby, I'd rather have two sets of eyes. My other question is that I have brand new Chevy Performance main cap bolts, and since I'm assuming the crank and everything need to come out to safely grind, can I reuse those bolts?
He's going to be there for guidance, he's built a ton of LS motors for the speed shop he works at. Since this is my first time and my GTO is my baby, I'd rather have two sets of eyes. My other question is that I have brand new Chevy Performance main cap bolts, and since I'm assuming the crank and everything need to come out to safely grind, can I reuse those bolts?
Yes, bolts are reusable. Clean everything very well before you re-assemble, including all oil galleries. Remove the barbell on the back to do this correctly. There will be metal shavings all over the place.
Take caution...there are water jackets in there somewhere...
Torque to yield bolts have a few torques in them or you would have to change the bolts from just a line hone. My rule is I never use them again if the motor was ran and this would be your 3rd torque if you did a line hone, so in my mind the last. The stock line hone is only off by a couple 10ths from the factory.
Tape up the oil passages in the mains and most of the metal will fall out through the cylinder. Then blow off the rest in the webs. Remove the tape and do a clean with brake cleaner and air. Your buddy will have his own process, so if you trust him, trust him.
Another "less messy" fix would be to remove that rod bolt and grind the head of it for clearance It will only lighten it a few grams ands shouldn't ruin the balance job
I've actually shortened the twelve point head to half its height and as long as you can torque it up with a quality brand socket it will be fine
No main bolts issues. No shavings. Nothing to clean but the rod bolt/s
Just remove the needed material and you'll be fine. If you're this worried about it, I'm sure you'll be extremely careful when doing this job.
All of the answers are in this thread. Tape up the oil galleys and take great care blowing out all leftover debri inside and outside of the block especially in the oil galleys.
(I would have cleaned the oil galleys anyways because you can't trust anyone and this just came from the machine shop)
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ARP2000 to block clearance? (402 LS2) 
