SSandman

I guess this could have went in the F/I section but it is really specific to the bottom end and I figured there would be some technical debate so it may belong here?

First off, how do you splay main caps on a motor if it already has 4 bolt mains? Im guessing material would be welded into the old bolt holes so the new holes can be drilled? Is this going to compromise the strength of the block over starting with a fresh 2 bolt main block?

What do all of you guys think about deck O ringing? I find so many mixed opinions on this when searching it is not even funny. Is it needed/necessary on a motor putting out less than 15psi? I plan to try to achieve my power levels through a well breathing motor with relatively low boost (wont see over 15psi).

How about head studs instead of bolts? Another mixed bag of opinions although my gut instinct tells me that SBC's seal pretty well so I don't think i'd need studs with 15psi or less.

thanks

Injuneer

Is this a stock 4-bolt LT1 block you are asking about?

SSandman

The block I have is a 4 bolt block, not originally (it's an LT1 block not LT4) but it was drilled out for std 4 bolt mains. NOT splayed however, but I wish to convert it to splayed due to the added stress on the mains from the blower.

Injuneer

I buddy of mine started with a stock 4-bolt LT1 block. 383, Vortech S/C making over 20# of boost and 1,125HP. The stock 4-bolt configuration held up fine to that level of power.... upgraded caps and bolts of course. The shop that built the engine took some measurements before commiting to keeping the straight bolt configuration. They seemd to feel that GM had done their homework in designing the LT1 block, putting the extra metal right where it belonged for the straight 4-bolt configuration. Drew parallels to the design of the Bowtie block, in that respect. They seemed to feel that drilling splayed holes where GM didn't intend bolt holes to be located might actualy produce a weaker configuration than the stock straight bolt setup.

Just a thought.

SSandman

Wow, thanks. I'll have to talk with my machine work guy about this and see what we come up with. It'll save me some cash for sure if indeed I don't need or shouldn't have splayed caps.

1racerdude

Keep what you have as Fred said.
The extra machine work isn't worth it. There is an ongoing debate as to which is stronger.
The block will fail before the streight 4 bolts and caps.

MachinistOne

Keep the block as is, I assume that the 4 bolt conversion uses studs?

For the kind of boost that you are talking about, a stock gasket with head studs will hold just fine. If you want to be extra safe, I like the SCE Titan ICS copper gaskets - no need to be doing an o-ring install on most blocks these days with the quality gaskets that are available.

rskrause

I use straight 4-bolt billet caps.

Rich