I did use the search button but it was nothing i was lookin for. So far on my research i have discovered that most say 2 bolts can oly handle 500hp. Now a true 4-bolt can handle well over a 1,000 fly. Notice i said true 4- bolt. Now what i wondering is most build up consist of a 4-bolt splayed conversion which is only 3 caps, where is the advantage of this over a studded 2bolt. I can see a little added strength but for some reason with out the end caps a conversion would be worth less.

Now side note: im a little old school but when i see 2-bolt ford motors with just bolt upgrades and old sbc 400 cranking out 700+ fly i dont see where are factory lt1 mains lack. Can some one fill me in? I ll i see in a splayed cap conversion is making the webbings weaker. Any articles,opinions, on this would be great. I tring to learn more about the engines structures(figuring out strenghts and weakness).

 

A "true" GM 4-bolt only has 4 bolts on the 3 center caps (at least on my 4-bolt LT1 block). The splayed 4-bolt end bolts go up into the main webbing on the side of the block, which spreads the loads into the block sides, as opposed to straight down next to the center bolts. You get some benefits from the triangulation. And the aftermarket caps are forged or billet, as opposed to the stock cast caps. I wouldn't try 1000 on a stock 4 bolt block.
Unless you are running a blower at high boost, the 2-bolt end caps are plenty strong, although I change them out to studs. I don't know of a conversion to 4-bolts for the end caps, and you would need a modified oil pan also.
The other thing is that the 4-bolt LT1 blocks are pretty rare, so adding the stronger splayed caps to your stock block makes sense.
On a high horsepower buildup, I like to fill the bottom of the block with block fill, up to the bottom of the side freeze plugs. I doesn't affect the cooling, and greatly increases the strength of the base of the cylinders, which see the most side loading. Do it before you bore though, it will change the bore slightly as it sets up.
You should also align bore the block if you change from bolts to studs, or at least get it checked. They pull the caps down a little different and may distort some.

 

theres no conversion "kit" for the end caps ive only seen it done twice many cause the cost is so high to do. And sorry for the type o but its not both caps done its just the front. I could almost swear the last time i seen a a 4-bolt lt4 block it the front cap was 4 bolt also... but i look to be wrong(poor white guy can only afford 2-bolt blocks) . So your saying that the actual bottom of the cylinder need to be strengthen. What else are weak point in the block???

 

BTW there are four bolt front and rear caps for the SBC(LT1 is just GenII)

I am thinking of getting my LT1 running again to get me by till I can finish my 18* motor. I am just going to run my 2 bolt block filled about an inch or so

I only plan on running 10s so it should be just fine

 

Why do you say "4-bolt LT1 blocks are pretty rare"..... other than the fact that the 10's of thousands of C4's that they used them in haven't made it to the bone yards in large numbers?

Baxter used the "stock 4-bolt" configuration for his 1,125HP 383/Vortech running over 20# of boost. Billet caps obviously... but a straight 4-bolt factory block. The block was sold after 4 years, was still in good shape, and is being reassembled in an 1,100HP nitrous configuration that is currently on the engine dyno. No fill was used in either application.

 

Straight 4-bolt is obviously plenty strong. IMO the splayed method is a bit overrated.

 

So here is a difficult question, at what hp level do the two bolts caps start moon walkin? I know every engine is different but a average wount hurt. Also how would say about 1/4 to 1/2 fill in the block work for a street motor i always try to stay away from filler unless it only sees track time.Any cooling issues??? Are there any other way to improve the the 2 bolt block.

 

I said "pretty rare" so far as availability at this time. Heck, it is hard to find a decent 2-bolt sometimes. Not too many C-4 owners want to part their car out.
I would agree that the stock 4-bolt is pretty tough, for a drag car that gets what, maybe 50 miles a year? 1/4 at a time. I have seen old style 400 SBC making 600 hp with a cast crank last an entire season. With 2-bolt blocks.
I am talking about the average guy that wants to build something to last a while, not tear it apart once or twice a season.

So far as helping it be stronger, studs in the mains, billet or splayed caps, totally deburr the block and remove any stress risers or sharp edges. And starting with a seasoned block is better, since it had already gone thru heat cycles and any and all core shift is done.