This is my 1st Olds 455 build and I dropped off my crank at the machine shop to be measured sinced both mains and rod journals were already .020 from a previous rebuild. The machinist said the rod journals can be polished to keep the .020 measurment but the mains must be grinded down to .030 and he does not recommend it and thinks I should get a new crank. Any advice will be helpful because I wasn't expecting to be buying a new crank since I'm on the last of my budget. He also recomends flat top pistons for a 10.5 compression with my e-brock heads. I already have the heads. The car will be street driven but may see the 1/4 mile a few just to find out how fast it is after the build. He doesn't recomend the .030 for a street car on the mains. Thank you guys for all your help. Hopefully I'll be done soon.

 

Here's what I know, right from the guys at Clevite;
The std and .010 under bearings share the same thickness shell(metal backing). The additional thickness for a .010 under vs std is taken up by the aluminum, babbitt etc. material.
A .020, .030 and .040 under bearings also share the same shell with each other, again with the difference being in the other layers.
So in essence a .030 under bearing should give the same support as a .010. And there is some cushioning effect with the added thickness of layers. Some say they absorb trash a little better too.

I'd grind it to .030 and not look back. However I'm not sure I'd go .040, not as much bearing support.

Jmo.

 

I still can't figure out why he said that but the machine shop is also a race shop for all makes. So should I leave the Rods .020 and grind the mains to .030 or grind both to .030? This is sort of bothering me because I was not expecting this. And don't have crank money in my build. Also does it matter if i use stock rods or eagle rods for a street car?

 

Never take off metal where you don't have to, .030" the mains and leave the rods .020".

As for rods, if you're planning to keep it under 550 HP there is no need to get the Eagle rods. Have them shot peen the crank and rods you have and they'll do just fine.

As for pistons, get the Keith Black IC886's...plenty of compression, they're light too...you'll be happy. Mark and I have both used them with great success...

Steve

 

Rebuilding stock rods and instaling ARP bolts costs about the same today as aftermarket rods that are much stronger. Stock rods are soft and the big end gets out of round too easily with high power and rpm, especially if you use heavy (stock weight) pistons and pins.

 

i agree with cutlassefi on the crank the only thing i would probably do in addition is have the crank nitrided again as the factory nitriding is most likely gone or will be at .030" under. if your stock rods are in good shape and your intended use is moderate performance then you'll be fine but Run to Rund is right about the $$ aspect of it... i've accumulated a couple sets of 425 rods and recently stopped by the machine shop to see about having them rebuilt & new bolts installed, holy crap!!
it will help if you run the lightest piston you can afford...

 

I had my stock rods rebuilt with ARP bolts for @ 160.00. I'm not making high HP, but didn't see aftermarket rods for less than 400.00...

 

Go with .030 on the mains,and leave the rods at .020.
I did one with .040's,and it is still fine/I think I did that engine in 2001 or so.
You don't neccessarily need a flat top piston,just because you have Edelbrocks,but you need a good piston.You also need to know if the deck was ever milled,and if so,how much.What do you want as your end result for compression?You can run 11:1 with pump gas,but that doesn't mean that you need to.

 

I was comparing costs with stock rods that had been sized, sides ground and shot peened, balanced, etc. True, a simple rebuild and bolts would be cheaper.