Would it be worth boring my 400 .30 over. what kind of power would it give me?
What mileage?

 

Welcome to FTE!

Yes it would.

Just so you know ,The 335 engine series forum is the best place to ask questions like this.
You can find it in the engine section of the forums

You can also do to your engine what this guy does to his 400's

http://home.earthlink.net/~bubbaf250/

btw, I was Born in Vanguard,Sask

 

I would only bore it enough to clean it up, you're going to gain very little cubic inches by boring it more than it needs.

 

I would look at the cost of getting it bored, how long you plan on having that block, and what you would gain from it. IMHO, I would not bore it for performance reasons. It's too expensive for netting only a few cubes. Put your money elsewhere and I think you will get more out of it. Just my .02

 

Try to look at your bigger picture. Are you changing pistons. If so what do you want to get compression ratio wise and what pistons are available. I would agree that if the block is in good shape just do the minimum. If you were to go say .040 over, like mine you would be at 408ci. No big deal. Going with Badger flat tops will net you around 9:1 cr. Also consider that if just a leanup of the cylinders is considered how much is come off and will you be able to get the proper ring end gap.

 

trust me boring you're block to make power will leave you very unsatisfied. The only reason for you to bore your block would be if it is needed, otherwise dont bother spending the money for a miniscule power increase. If you're looking to make some cheap power slap on a set of headers or something. I am running a set of headers i bought for 120 on jegs and am very happy with them.