4 bolt lt1?

[Caveman]

so ive been thinking about trying to push some more power out of my lt1..ie turbo(s).. im really worried about the mains though... i really dont like the 2 bolt set up at all..but i love my lt1...Id love to have a little less worry of my bottom end.. anyone do a 4 bolt conversion? on any engine..not just lt1..

Id be willing to cough up the money..just not sure how to do it or who to have do it.. any ideas/suggestions? thanks!

[DETROITMUSCLE]

may I ask why wouldn't you consider an LS swap? They are much more boost friendly in stock form or fully forged.

[Caveman]

ive already got a pretty substantial amount of money put into the block already. maybe down the road ill do an ls swap but im not ready for that yet.
that and i just like the lt1 a lot...

[meissen]

From what i understand, a splayed 2 bolt is stronger than a standard 4 bolt.

[Caveman]

From what i understand, a splayed 2 bolt is stronger than a standard 4 bolt.

splayed 2 bolt? can you elaborate a little? im still kinda a noob..

[JoeliusZ28]

I was going to say the same thing but i dont exactly have the answer for you. I believe "splayed" refers to a specialized, beefy, variety of main cap.

do some searching on camaroz28.com - lots of good info there.

Also LS1s are indeed much more boost friendly.

[meissen]

Splayed is when the bolts are angled outward. Stock is vertical. With the bolts being angled, it's believed to make it stronger and stop movement of the cap.

If I understand it all correctly, it goes in this order:

Stock 2 bolt < Stock 4 bolt < Splayed 2 bolt < Splayed 4 bolt

I've read that stock 2 bolts are good up to 500hp, stock 4 bolts have handled about twice as much but they have a weak point in the webbing because GM drilled the outer holes too deep on the 4 bolt block.

Then again - there's a guy floating around on CamaroZ28 and LS1Tech that has a stock 4 bolt (upgraded bolts and mains, of course, but no added metal to the block) pushing well over 1,000hp.


Here's a good picture of splayed main caps:

[MunsterZ28]

good info B did no know that

[my95z28]

A factory four bolt main block is much stronger than a factory two bolt block. Corvettes came with four bolt main blocks. There have been reports that some F-bodys might have gotten 4 bolt mains toward the end of production, probably because they had left over corvette Lt1s built that they didn't need.

A splayed two bolt main is stronger than a factory four bolt main block. You get a splayed two bolt, by taking your block and caps to a machine shop, and they convert it to a four bolt, with a more aggressive rod angle. The more aggressive rod angle makes the splayed two bolt stronger than the factory four bolt.

Regular four bolt main


Splayed two bolt

[Caveman]

thanks! yeah i just found that out about the splayed caps on camaroz28..

i have a stock 2 bolt..so splayed caps are pretty much out of the question i take it.. can i have my block milled for a 4 bolt? do they do a 4 bolt cap with inner 2 straight (to utalize the existing holes) and the outer 2 splayed maybe?

also..how do i know if i have 350 mains or large journal? its the stock replacement lt1 ordered through autozone when i blew my origonal one up..

[my95z28]

B beat me to it. So wait, there are jsut 2 bolt mains that are splayed, IE two bolts per main, just angled outward? I don't think thats right Brian, the reason they can angle the outer bolts, is because they are completly drilling & tapping them from scratch. I think that a splayed 2 bolt, means there are actually 4 bolts now.

[Caveman]

the pic says splayed 2 bolt but theres 4 holes... am i missing something or is that just a typo

[my95z28]

the pic says splayed 2 bolt but theres 4 holes... am i missing something or is that just a typo

Read my post above you, I'm 90% sure that a splayed 2 bolt = a 2 bolt that has been converted to a 4 bolt main, with the outer bolts on an angle.

[meissen]

I'm not sure - I've read people specifically call some jobs a "splayed two bolt" and other jobs a "splayed 4 bolt."

Edit: Looks like there's no such thing as a splayed two bolt - it's really a splayed 4 bolt?

[Caveman]

Read my post above you, I'm 90% sure that a splayed 2 bolt = a 2 bolt that has been converted to a 4 bolt main, with the outer bolts on an angle.

summit just says splayed 2 bolt is just that...two bolts, just angled.. splayed 4 bolts are 4 bolts..

would something like this work for me?
http://www.summitracing.com/parts/ES...S/?image=large

says the outer bolts are splayed..but dosnt say anything about the inner bolts..could they be straight? would that work? like a 4 bolt cap with two straigh and two angled? i still am not sure if i have large journals or 350 mains..whats the difference?