Searching for LT1 4 - bolt main block!
07-02-2013, 08:13 AM
#1
Searching for LT1 4 - bolt main block! Is their anyone in this forum selling or knows anyone who is selling a LT1 4 bolt main block? Just trying to save money on getting the caps splayed even though its potentially stronger than factory 4 bolt main. Let me know, very interested.
07-02-2013, 09:23 AM
#2
Shipping engines is not cheap...unless some local junkyard has a LT1 Corvette around, you should probably look into getting your 2 bolt LT1 splayed, or do a real upgrade to a LS 
It has 6 bolt mains, which by my calcuations, makes it 3X better than your 2 bolt LT1 
It has 6 bolt mains, which by my calcuations, makes it 3X better than your 2 bolt LT1 
07-02-2013, 09:18 PM
#7
By the time 4-bolt really matters vs. studding the 2-bolt you should be looking at aftermarket caps anyway. The machining plus having paid a premium for the block means no savings.
The guy with the fastest NA Impala putting 500ish rwhp down runs studded 2-bolt, but everyone here building a mediocre stroker wants to spend the cash on 4-bolts and "save" money on the topend. If you have the cash to spend great, if it is going to cause you to cheap out somewhere important like topend maybe reconsider.
The guy with the fastest NA Impala putting 500ish rwhp down runs studded 2-bolt, but everyone here building a mediocre stroker wants to spend the cash on 4-bolts and "save" money on the topend. If you have the cash to spend great, if it is going to cause you to cheap out somewhere important like topend maybe reconsider.
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07-03-2013, 02:39 PM
#8
Either go with a two bolt......or splay your block. The GM OEM 2-bolt is a pretty damn strong block.....and the OEM 4-bolt is weaker than what a good machinist would do for ya.
KW
07-04-2013, 05:51 AM
#11
07-04-2013, 01:27 PM
#13
I picked one up here on the forums. complete shortblock shipped from Va to NY for $400 just gotta find one. I am going for a stock 4 bolt main because if you look at the webbing its stronger in the stock location then if it were to be splayed. just my .02 tho.
07-04-2013, 01:30 PM
#14
My issue with a .060" overbore ain't the 4-bolt mains, it's the .060" boring.
This is generally considered the max you can bore a LTx engine without cutting into the water jackets. The engine is still servicable, just that you may not have the wiggle room to cut the bores in the future.
The fact that the engine already has 4-bolt mains is a small bonus over a two-bolt engine.....NOTHING at all wrong with that
!!!KW
07-04-2013, 06:20 PM
#15
The LT1 4-bolt blocks are the same castings as the 2-bolt.
Guys with stout 383 setups can see bore movement in NA LT1s at a .030 overbore and given enough time crack the deck or a bolthole to a bore.
If I were going to even consider a .060 over bore I would want to see the receipt for the sonic test. There are those who use a.060 overbore but anyone with a clue would do so cautiously and sonic test the block first.
Far as further cleanup on future rebuild how about just getting the bore and hone right for whatever new pistons you order?
07-05-2013, 07:44 AM
#16
The splayed vs. straight argument gets beaten to death but honestly if making enough power both are upgrades over 2-bolt so it seems to be splitting hairs.
The LT1 4-bolt blocks are the same castings as the 2-bolt.
Guys with stout 383 setups can see bore movement in NA LT1s at a .030 overbore and given enough time crack the deck or a bolthole to a bore.
If I were going to even consider a .060 over bore I would want to see the receipt for the sonic test. There are those who use a.060 overbore but anyone with a clue would do so cautiously and sonic test the block first.
Far as further cleanup on future rebuild how about just getting the bore and hone right for whatever new pistons you order?
The LT1 4-bolt blocks are the same castings as the 2-bolt.
Guys with stout 383 setups can see bore movement in NA LT1s at a .030 overbore and given enough time crack the deck or a bolthole to a bore.
If I were going to even consider a .060 over bore I would want to see the receipt for the sonic test. There are those who use a.060 overbore but anyone with a clue would do so cautiously and sonic test the block first.
Far as further cleanup on future rebuild how about just getting the bore and hone right for whatever new pistons you order?
07-05-2013, 08:14 AM
#17
LOL!!!
That's .015" wall thickness. Do people really think sonic testing can get it that close? Not that I have seen after cutting a couple of blocks apart.
Btw, LT1 blocks are not "really strong". They are typical late model GM thin wall castings, of shity cast iron. If you ever start to make any power (not talking 400) you are going to have a hard time keeping your cylinders straight. Rings don't seal in cylinder walls that move around. Fill the water jackets, and when you put it back in the hone at the end of the season, and first pass with the hone you will see where the grout stops. That costs HP.
That's .015" wall thickness. Do people really think sonic testing can get it that close? Not that I have seen after cutting a couple of blocks apart.
Btw, LT1 blocks are not "really strong". They are typical late model GM thin wall castings, of shity cast iron. If you ever start to make any power (not talking 400) you are going to have a hard time keeping your cylinders straight. Rings don't seal in cylinder walls that move around. Fill the water jackets, and when you put it back in the hone at the end of the season, and first pass with the hone you will see where the grout stops. That costs HP.
Last edited by Ed Wright; 07-05-2013 at 08:17 AM. Reason: Still can't type
07-05-2013, 04:04 PM
#20
I kn ow girdles are popular on Furd 302s. If it were a good way to strengthen a SBC I think we would see more of them and from some decent companies. I think the particular weaknesses in each block design demand different solutions and just because a girdle is a good addition to one engines doesn't mean it is the answer for another.