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i have no real stats, but a 2 bolt can handle a 383.

i would recomend balance it and dont spin it above 6000 rpm
 

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How much stronger is a 4 bolt main than a 2 bolt and how much HP can a 2 bolt 383 handle.
HP isn't really the problem, RPM is. If you don't plan on spinning over about 6500-rpm, a 2-bolt will be fine.

Personally, I feel 4-bolt blocks are overpriced and overrated. A good 2-bolt block with quality aftermarket studs is stronger than a 4-bolt with factory hardware.

Use the money you save buying a 2-bolt block to buy quality studs instead.

Old threads about this topic:
http://stevesnovasite.com/forums/showthread.php?t=84498
http://stevesnovasite.com/forums/showthread.php?t=84435
 

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How much stronger is a 4 bolt main than a 2 bolt and how much HP can a 2 bolt 383 handle.
that really depends.. on machine work, block prep, selection of parts, quality of the block, quality of parts selected, your foot, expected longevity..

too many variables....

the 4 bolt 400 vs the 2 bolt 400 was and has been debated for years....

One person I respect, has seen little to no difference in the two...

I suspect it would have more to do with weight of the car and intended use rather than strength of the block or ability of one block over the other......
 

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i have no real stats, but a 2 bolt can handle a 383.

i would recomend balance it and dont spin it above 6000 rpm

Definitely get it balanced. :yes: I ran a 2 bolt 383 (approx. 500 hp) in my drag car for 4 years. I shifted at 5600 rpm and went through the traps at around 6000 rpm. It held up perfect.
 

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can someone explain what a bolt is, 2 bolt and 4 bolt..is that something you can do to the block?
What we are talking about is the amount of bolts used to attach the (middle 3) main bearing caps to the block itself.

A 2-bolt block uses 2 bolts (1 per side of the crank) while a 4-bolt block uses 4-bolts (2 bolts per side of the crank).

Standard two bolt production block:


Standard production 4 bolt block:


Aftermarket splayed bolt 4 bolt main cap block:
 

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For what it's worth, the guy that has built three SBC for me, two of them currently reside in both my cars, laughed when I first insisted that he build me a 4-bolt engine. He said the 2-bolt works just fine and that 4-bolts are overrated and it's just an old wives tale. I figured he should know, he has been building racing engines for decades. He said most of the local roundy round dirt guys use 2-bolts with no problems.
 

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oooooo ok i get it now thanks alot for making it easy to understand..but how do you do that to a block? is that something you can do it any block?
You can do it to just about any 2-bolt block. Basically you just drill and tap. The factory did 4 bolts parallel to each other. Aftermarket splayed bolts are on an angle. The middle 2 are straight like normal but the outside 2 are on the same angle as the sides of the block. You really can’t add splayed bolts to a factory 4-bolt block.

Personally, I think the extra holes weaken the block. Most things don't gain strength when you drill holes in them. But that's just my opinion.
 

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You can do it to just about any 2-bolt block. Basically you just drill and tap. The factory did 4 bolts parallel to each other. Aftermarket splayed bolts are on an angle. The middle 2 are straight like normal but the outside 2 are on the same angle as the sides of the block. You really can’t add splayed bolts to a factory 4-bolt block.

Personally, I think the extra holes weaken the block. Most things don't gain strength when you drill holes in them. But that's just my opinion.
who do you know what bolt you have? i have a stock 350 so im curious
 

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And the extra bolts aren't mainly for block strength, they're to keep the caps from walking around at high RPM. Big block's euse 4 bolts, but enen their 2 bolt mains are strong. They use a registered main cap to keep them located. Pontiacs use dowl pins. here are many ways to do thins. I'd like to see an aftermarket main cap for a SBC that uses dowl pins to positively locate the caps. This would leave alot more material in the main webs of the block casting.
 

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he means, tale the oil pan off and see what caps you have.

you cant lawys run the numbers, it has to be visual
 
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