I went to install the rods into the 350 I'm building and it turns out that I have a massive side play of about 25 thousandths. I measured the crank and rods and it turns out that the rods are to thin about .938 inch. Does anyone one know if there is anything you can do to fix this other than getting different rods? Is there like some shims or something you can put in there to make them work?

.025 is the upper limit, but still in spec. It's measured by spreading the rods aparts and measuring between them with a feeler gague.

Rod side clearance is one of the least critical dimensions in the engine.
I don't recall ever assembling an engine with OEM rods that was within spec.

on performance,, i use .015 as the minimum spec and like said,, about .025 for the max. iirc,, most of the time,, end up opening up the sbc's for clearance. think they are about .943-.944 stock width each rod in stock form. with .015,, that gives a theoretical .005 between each of the 3 oil leak out points at the big end of the rods. just my thoughts on it. i can't see it seroiusly hurting anything with it as much as .030,, but might knock just a tad. and probably wouldn't notice it over an open exaust.

most bbc stock setups are anywhere from .022-.027 anyway. don't think i've ever seen them tighter than .020 even stock.

if it was me,, i'd probably run it and never think twice about it. but that's me.
hope it helps.

I too would run it with .025" side clearance and never miss a moment's sleep over it. FWIW some aluminum rods want in the order of .050" side clearance.

We have worked on sone piston guided rod engines that have almost .100 side clearance and no oil pressure problems.

You have to remember its the bearing clearance the regulates the oil flow between the rods not the side clearance unless you had under .008 side clearanc then it would restrict the oil flow and in turn burn up the bearings.

We have some of aur engines we build that have up to .040 side clearamce and no problems with any knocking.

Rindoze, no need to shim, ( its impossible anyway;-) the guys who answered above must have a few thousand SBCs and other North American V-8 engines under their collective belts by now;-) .025" is not a show stopper of any kind.

Rindoze, Glad to hear your finally putting your engine together. how did the heads turn out? Don't worry about that much side play. I've seen worse run with no problem.

We have worked on sone piston guided rod engines that have almost .100 side clearance and no oil pressure problems.

You have to remember its the bearing clearance the regulates the oil flow between the rods not the side clearance unless you had under .008 side clearanc then it would restrict the oil flow and in turn burn up the bearings.

We have some of aur engines we build that have up to .040 side clearamce and no problems with any knocking.

exactly,,, as long as the side clearance isn't pinching off the flow path of whatever the bearing clearance is. that's my thoughts as well. more of an area of clearance exit area. good info on the .040 without knocking. thanks cnc. never tried that much.

Rindoze, no need to shim, ( its impossible anyway;-) the guys who answered above must have a few thousand SBCs and other North American V-8 engines under their collective belts by now;-) .025" is not a show stopper of any kind.

Not quite up to the numbers you mentioned but we are getting there.

maybe,,, pretty close,,,,,,, 4 years on the builders table in production doing an average of 4-6 shortblock assembly's a day,, monday through friday. floated arround to some machines during that time though. but maybe getting really close when adding in the others when out of production environment,, like 2-4 a month in a custom machine shop environment. full machine work getting done as well. over 16 years total time in machine shop's. 30+ years messing with engines i guess,, since my beginning. never really thought about the shear number of them before. huhh.

Rindoze, Glad to hear your finally putting your engine together. how did the heads turn out? Don't worry about that much side play. I've seen worse run with no problem.

Thanks again for those heads man. Couldn't find any real problems on the heads, just need some new seals and springs. Lots of carbon buildup on the intake valves though. But about the side clearance I appreciate all the input I was just worried because specs I saw for rod side clearance was 8 - 14 thousandths and the rod seems like it would wobble during operation (I can wiggle it on its sides some) but no up and down play. The rods are chamfered if that makes any difference.

correction there seems to be up and down play because I can cock the rod sideways. Plus I need to clearance the block because the rod bolts hit the block