whats the better block for me to build up? 2 bolt or 4 bolt lt1?i
#1
whats the better block for me to build up? 2 bolt or 4 bolt lt1?i
I'm planning to build a forged solid roller 383 forced induction,meth injected ltx. Afr comp ported (or trickflow) 210 cc heads
I'm hoping for 650 rwhp w a p1-sc blowr (that's what I have currntly) making 12 psi or so boost.
Later on, I'm hoping to fit in a bigger head unit and make 18+ psi boost and app. 800 rwhp.
What kind of block should I be looking for? Should I reuse the one I have? Build another on the side?
If I build another on the side, then do I want 4 bolt (corvette) or 2 bolt?
Btw this is on a 93 corvette.
Also, does anyne have any recommendations on who builds ltx motors?
I'm hoping for 650 rwhp w a p1-sc blowr (that's what I have currntly) making 12 psi or so boost.
Later on, I'm hoping to fit in a bigger head unit and make 18+ psi boost and app. 800 rwhp.
What kind of block should I be looking for? Should I reuse the one I have? Build another on the side?
If I build another on the side, then do I want 4 bolt (corvette) or 2 bolt?
Btw this is on a 93 corvette.
Also, does anyne have any recommendations on who builds ltx motors?
#2
Re: whats the better block for me to build up? 2 bolt or 4 bolt lt1?i
I would pick the 2 bolt block you want to use, have the cylinders sonic checked, the whole thing magnafluxed for cracks, and if it's good, put splayed caps then have them blueprint the whole thing. What kind of compression and cam were you thinking of? Because a (big) solid roller cam won't work down low and neither will the centrifugal blower.
Last edited by Kevin Blown 95 TA; 10-04-2011 at 04:49 PM.
#3
Re: whats the better block for me to build up? 2 bolt or 4 bolt lt1?i
You'll get a lot of differing opinions on this. If you're committed to 12 psi on a 383, you pretty much have to go 4-bolt. The question becomes, do you run a factory 4-bolt, splayed conversion, or straight conversion.
I was running 20+ psi on a 383 on a straight conversion.
The factory 4-bolt blocks have been proven to very high hp levels, even with the cast caps. Theoretically, the billet caps supplied in conversion kits have much higher tensile strength, but it's pretty dang rare that someone actually breaks a main cap.
As for straight versus splayed, people will argue this til they're blue in the face. I can only think of disadvantages of splayed when compared to a straight conversion. Some say that the splayed cap puts the bolt threads in a weaker, thinner part of the block. I have to way to know if this is true. However, from a bolt loading standpoint, the register-fit retains the cap laterally and the bolts vertically. By putting the bolts at an angle, you don't improve the lateral stability, but you do reduce the bolts vertical holding power. Furthermore, they are more expensive and difficult to install.
Another thing to consider is that the factory 4-bolt caps have the register fit at the very edge, whereas conversion caps have the register between the bolts. This makes the conversions more difficult to repair if you spin a main and have to machine the mating surface to close up the main bore.
In short, if you have a factory 4-bolt main block, use and it never look back. If you have a 2-bolt block, convert it. Read up on the straight vs. splayed debate and make your own decision, but realize that you won't break either one.
I was running 20+ psi on a 383 on a straight conversion.
The factory 4-bolt blocks have been proven to very high hp levels, even with the cast caps. Theoretically, the billet caps supplied in conversion kits have much higher tensile strength, but it's pretty dang rare that someone actually breaks a main cap.
As for straight versus splayed, people will argue this til they're blue in the face. I can only think of disadvantages of splayed when compared to a straight conversion. Some say that the splayed cap puts the bolt threads in a weaker, thinner part of the block. I have to way to know if this is true. However, from a bolt loading standpoint, the register-fit retains the cap laterally and the bolts vertically. By putting the bolts at an angle, you don't improve the lateral stability, but you do reduce the bolts vertical holding power. Furthermore, they are more expensive and difficult to install.
Another thing to consider is that the factory 4-bolt caps have the register fit at the very edge, whereas conversion caps have the register between the bolts. This makes the conversions more difficult to repair if you spin a main and have to machine the mating surface to close up the main bore.
In short, if you have a factory 4-bolt main block, use and it never look back. If you have a 2-bolt block, convert it. Read up on the straight vs. splayed debate and make your own decision, but realize that you won't break either one.
Last edited by engineermike; 10-08-2011 at 08:25 AM.
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