Jrod2011

So I am currently in the process of building a 392 stroker. I am using a 1978 318 block with 1968 heads so no pollution BS. I have been looking at a couple of rotating assemblies that will bump my stroke from 3.31 to 4.0 inches. I am doing all the work zero decking the block and boring it .040 over. My question is if I am going to have to do any machining to the block with the bigger crank? I know making a chevy 350 into a 383 stroker you have to mill the sides of the block out so the crank bolts don't hit it. I just never stroked a 318. I am using the rotating assembly from Campbell Enterprises you can check it out here https://moparforums.com/forums/newth...newthread&f=81
So I need to know what all I am going to need to do for the block to accept this crank. Any guidance is appreciated.
Thanks!

TVLynn

Most likely you will need to do some grinding So a trial assembly is mandatory You may save some room by using ARP rod bolts if the kit doesn't come with them- they are 12 point I would also think hard about some ARP main studs

PK1

I couldn't open the link but most SCAT kits with I beams fit without modifying.

You should always mock up the assembly and check. You can do this after machining and should do to confirm that your machinist theoretical "zero" deck is correct.

Jrod2011

Thanks for the help i'll have to look into the ARP kits. Was going to for sure check everything anyway. The zero deck height shouldn't be to big of a problem with the flat top pistons with valve relief. Should have the appropriate clearance between valves and top of piston. But will check for sure. Thanks.

Jrod2011

sorry posted the wrong link in the initial posting. the rotating assembly can be seen here
http://www.campbellenterprises.com/3...roker-kits.php

PK1

Suggestion for you and some stuff that has helped in the past.

If you haven't built a motor like this consider the following.

Buy the kit unbalanced without rings and bearings. Make sure they have a good return policy or will swap pistons if you need. You can check your current bore to ballpark your overbore circumference but wont know how it cleans up until its machined.

Select an engine shop that does some normal machining for rebuilds and NOT a parts store machine shop that does some engine building. The former should cost 10-20 percent more but its well worth it.

Have the shop do the balance and check the clearances on the block and crank for you. They will spec you a bearing. This puts critical measurements in their hands and they have the tools for it. You may want them to file fit your rings. The cost is not that much more if you don't already have the grinder. If you get a bad ring or he needs a "do over" he usually has many of what he uses on hand.

Jrod2011

Thanks for the advice but I am doing all the machining work not taking it to a shop. I already bored the cylinders to .040 over thats done and out of the way. I had already decided to do the file to fit rings. I provided the proper clearance when i was honing the cylinders. Although I do not have the ability or know how to balance a crank, or adjust the block for clearance. That is why I asked what I have to do to account for clearance. A buddy of mine has a mock up crank that you can adjust the rods out to see if it will hit or not but was not sure how much i could trust that. And about the return policy I do not know about that site i posted above has anyone used them before?

Thanks

PK1

Several things come to mind and don't take this the wrong way, if you already know it forgive me for mentioning it.

Final bore of a cylinder is determined by the piston manufacturer and its rate of expansion. Forged vs hyper vs cast all have different bore requirements as they all expand at different rate. The professional builder will know how to sneak up on the tolerance or back off based on power achieved and review of their print notes from prior builds.

The piston manufacturer will spec clearance for rings. They are all different.

If you have these notes in hand and already did the work then you are ahead of the game.

The 392 is no different from a gen1 Chevy 383 mil. The only place you will need to remove material is on the pan rail if at all BUT check the bottoms of the bore skirts too. I have used I beams and had no issues but you are using H beams and I don't know if the rod bolts stick out more. I would still mock up anyway as production materials vary. I use a sharpie or dykem and a scribe. I have a carbide bit on a variable speed hand grinder. Remove in small amounts.

I have no clue how you balance a crank at home. You can buy it balanced if you want to. Some check out just fine. I just prefer to have mine done locally as I dont want to go back in after its installed.

Jrod2011

Thanks for all your help PK I appreciate it. If you don't take free advice your stubborn haha. I appreciate and I will have to look into somewhere that balances cranks I agree it would be worth the money to have it done right the first time. I was aware of the piston ring clearance though but I can completely understand how it could be over looked. Thanks again for all the help.

TVLynn

Just in case??? Put it together without the rings, torqued down to specs. Don't forget to re wash everything before the final assembly