So this isn't exactly an LT1 specific question, but I feel like I know half of you guys from reading your posts so often, and I feel more comfortable posting here.

I've got a bare 350 block that I want to get rid of. It came out of an early 80's Chevy truck and has 4-bolt mains, but the main caps are missing. Just posted it on craigslist and got a response from an interested person.

He asked me about the block and I gave him the details, he then told me that without the main caps the block is scrap.

That's about when my bullshit detector went off. I don't know a whole lot about building engines, but his statement doesn't really make much sense to me. I was under the impression that you could just buy new main caps and have the block align bored, good as new.

Is this guy right or full of ****?

 

He's right. Without the caps the block is garbage. There's no way to restore the block's original crank centerline without them.

 

^^ Really? I've never heard of that.

 

Call any reputable machine shop and ask them if they would recommend building a block with no caps and see what they say.

 

So answer me this: Why does anyone ever replace stock main caps with aftermarket caps, if it's so critical?

 

you have to have it line honed if you replace the caps which equals more money than its worth to the average person cause 350 blocks are a dime a dozen and the average guy doesnt need upgraded caps.

 

This is the same thing you just said, which is what I thought. And getting a block line honed is no big deal.

And a lot of us aren't average guys. If you're going to build a 350 (unless it's for a restoration), build it BIG and make some power. In that case, upgraded caps are a good idea.
I would have been nuts to use stock caps in my motor.

 

Most everyone who replaces caps do not replace the front/rear caps. I should clarify- I have talked to three different machine shops about this in the past and all of them state the front/rear caps are critical to have when doing a line bore/hone. If all caps are replaced the only thing I can think of is the stock front/rear caps are used to line bore and after the inside caps have been done then centerline can be referenced enough to have front/rear caps line bored/honed.
You can easily rebuild a block using new caps w/out the originals. The question is if the crank is riding on its true centerline and if it isn't, how long will it last.

 

Well this has been educational to say the least. I appreciate everyone's input on this one.

At this point I'm almost ready to drop the block off at the scrap yard and take my twenty bucks, but I think I'm gonna leave it posted for a bit and hope I have better luck with the next person.

It'll probably sell, seeing that I'm not asking much more than scrap value for the damn thing. Plus craigslist is free so I've really got nothing to lose.

 

You can replace the caps. Like mentioned earlier your block would need to be line honed to make sure everything was straight. If it was me though I would look for a block with the caps.

Unless its absolutly necessary I wouldnt line hone anything. It moves the crank closer to the cam and can effect your timing.