I bought a 4bolt 350 that didnt come with the main caps that hold the crank shaft. so i ended up buying some off of ebay. now the engine has had some machine work done to it. so when my freind took a look at the engine he told me that i have to make sure that the main caps i bought are the right size. He explained to me that some machine shops use a certain process to find the size. But my local machine shop doesnt know how to do it. I live in palm bay florida if anybody knows of a machine shop that can do this please help me out. Thanx

 

Do you have these caps? You can get a measurement by using caliper, but if the block or caps have ever been align bored/honed, then they won't work with each other. You might have to have them bored/honed together.

What kind of machine shop can't measure a bore? We have several dial bore guages, some accurate to .00001"

 

There's no real "process" for measuring them... it would be pointless anyway, because whenever you take caps that were machined for one block and bolt them up to another, they're ALWAYS wrong.

What has to be done, is to take the caps, and cut a little metal off them; bolt them up to the block; then re-bore the crank journals. The name of the operation is "align-boring". It'll cost around $125-175. Most any competent racing machine shop can do it.

You'll find that it costs more to do that, than buying a whole other block. You'll have enough money tied up in all that, to where you could have bought probably 2 blocks WITH their caps. I would advise against it. Cut your losses now. Sell the caps to the next "greater fool" (yes, there's always one out there...). Go buy a complete block. They're EVERYWHERE, and cheep.

Lesson being: if a block doesn't have its main caps with it, and you're not going to install splayed-bolt ones, it's not worth buying.

 

If you've already sunk $400 or so of machine work into it, (bore/hone, deck, etc) then you'd better continue, it wouldn't be economical to find another block and start from scratch again.

I didn't think you'll need to align bore it, maybe just align hone it. I paid $125 for that because I didn't mark which cap went where. $125 lesson I won't forget...

So you told the machine shop you bought new caps for the block, and you want the guys to "make 'em fit", and they looked at you and didn't know what to do? I'd grab my stuff and RUN FAR from that machine shop. That screams incompetence. My machinist didn't even bat an eye when I handed him a mixed baggie of main caps which were unmarked. He just wrote down the price for an align hone job on my price quote and told me why I needed it. When i'm paying $120/hr for machine work i'd damn well better get some free expertise out of the deal!

 

$120/hr! We need to raise our prices soon.

They actually gave you a break on the align honing, then. Setup on something like that usually takes .5-1 hr alone, unless they just finished a SBC and bolted yours in place.

 

Well they do a lot of SBCs I imagine. I dropped $2k there, so they did toss in a few freebies... Installed pistons to rods free, little things like that.