Lt1 block Q's 2 bolt vs 4 bolt
I have heard that on some blocks it is weaker to go 4 bold as you say due to the lack of material, I just left mine up to my engine builder, He says its ok then I will let him be the judge, If you judge him, just to let you know he ONLY builds very high end Pro Motors,Like I said at 648 RWHP my caps danced around so I am hoping going 4 bolt will give me a little more stability....
If not, then maybe he isn't being critical of a 'lowly' LT1... Just because someone only builds high-end motors doesn't mean much. It can mean they are ciritical in EVERYTHING they do and will do things properly. It could also mean they are pompous ****** and don't cover the fine details on something as 'low-powered' as your average LT1 mill...
Sorry, been in this game long enough and know enough people to know that just because a shop/builder CAN do awesome high-end work doesn't mean they will all the time. Some base thier 'critical attention' only on those projects whose dollar amounts demand it. Sad, but true.
I hope it all works out for you.
As a side note I still assemble all motors I will be putting my name to. I double check all the machine work done, tedious and time consuming, but I have yet to have a failure due to somethingbeing overlooked and have caught various things that others would have just let go. It ALL comes down to the details. It is not about trust, it is about doing it once and doing it right.
I think it would also depend on what angled degree splayed caps you use. A lower angle degree would be closer to a straight cap resulting in assuring more material to play with. Correct?
I have a 2 bolt with ARP main studs... I'm wondering how much this will be able to hold? Also if I put callies caps would it be able to hold 1000hp? being a 383 boosted..
Sorry, any of you saying a splayed 4-bolt LT1 block is better than a 4-bolt straight converted or stock 4-bolt block absoloutly DO NOT know what you are talking about...
The LT1 blocks have less material in the webbing, thus a 4-bolt splayed LT1 block is weak by lack of material.
A factory 4-bolt block, or even better yet, a shop converted 2-bolt to straight 4-bolt block is the best you will have on a LT1.
For other blocks a 4-bolt splayed may be the best, but FOR SURE not on a LT1...
It is just amazing how stupid the responses get when a few people in the know stop posting... This was a known fact about LT1 blocks FOR YEARS! I mean WOW, a bunch of guys here just read an article and think they have a clue, or hang around some old-school guys and think they can just repeat what they heard without having any idea about what they are 'experts' in...
Hell, most of us knew this back in 1998-1999... It is pretty damn easy to even compare the amount of material in the webbing vs some of the older style blocks... It is quite visible that the LT1 blocks are light in that area.
It is just amazing that no-one else even mentioned this well-known 'FACT' of LT1s...
Then again, most of those with a clue just refuse to post, or don't care about the boards anymore due to all the stupidity going around... Hmm, maybe it IS time to move onto the LSx motors???
The LT1 blocks have less material in the webbing, thus a 4-bolt splayed LT1 block is weak by lack of material.
A factory 4-bolt block, or even better yet, a shop converted 2-bolt to straight 4-bolt block is the best you will have on a LT1.
For other blocks a 4-bolt splayed may be the best, but FOR SURE not on a LT1...
It is just amazing how stupid the responses get when a few people in the know stop posting... This was a known fact about LT1 blocks FOR YEARS! I mean WOW, a bunch of guys here just read an article and think they have a clue, or hang around some old-school guys and think they can just repeat what they heard without having any idea about what they are 'experts' in...
Hell, most of us knew this back in 1998-1999... It is pretty damn easy to even compare the amount of material in the webbing vs some of the older style blocks... It is quite visible that the LT1 blocks are light in that area.
It is just amazing that no-one else even mentioned this well-known 'FACT' of LT1s...
Then again, most of those with a clue just refuse to post, or don't care about the boards anymore due to all the stupidity going around... Hmm, maybe it IS time to move onto the LSx motors???
my next build will be a studded 4-bolt block.
Well there is another option if you money is tight, you can buy a sbc main girdle which bridges all 5 main caps together and will strengthen the bottom end for added insurance. I got one from ebay for like $75 bucks and I'm going to use it on the engine I'm taking out of my car to install my 383. I'm going to rebuild the stock engine withe forged rods and pistons with a polished stock crank and keep it as a spare in case anything happens to my 383.
YEP and thats why I did 10* splayed caps instead of 22-23* caps. The 22+ degree caps also tend to hit the water jackets if drilled to far.
On The Tree
Joined: Jan 2004
Posts: 105
Likes: 1
Just curious how often people convert the two outer caps as well? I went with just the three center billet caps. With all five studded its still probably a bit overkill for my setup, but considering these relatively small pieces hold the entire assembly together (and all the HP from rocketing out the bottom of the engine), its worth the peace of mind...
Last edited by DVS LT1; Jun 14, 2022 at 10:54 PM.
From what I understand, the factory four bolt blocks are stronger than converted mains, because in a factory block, the webbing is CAST for the extra bolts. With converted mains, you're drilling into webbing designed for a 2-bolt block.
A very reputable engine builder told me this, so go easy on me.
A very reputable engine builder told me this, so go easy on me.
TECH Regular
Joined: Jun 2009
Posts: 448
Likes: 0
From: new york
like said before , in a lt1 your gonna hurt a rod before the crank or mains get hurt . im on a a.r.p studded 2 bolt block because the material wasnt there for a splayed 4 bolt setup . my machinist said i was safer on a studded 2 bolt also . i spool mine up to 7k at the track with a 200 hit under it all the time as long as its tuned right your relativley safe . BUT IN THE END ANYTHING WITH THE RIGHT AMOUNT OF ABUSE WILL BREAK
The comments about the 2-bolt blocks not having the material for the 4-bolts to tap into are based on
OLD BLOCKS NOT LT1s
This has been covered over and overbut people insist on bring in outdated "information", the 4-bolt LT1 blocks are the same block as the 2-bolt.
Read carefully I am not saying your engine guys are wrong about some blocks, just saying they are miss applying an old gen 1 issue to the gen 2 motor.
OLD BLOCKS NOT LT1s
This has been covered over and overbut people insist on bring in outdated "information", the 4-bolt LT1 blocks are the same block as the 2-bolt.
Read carefully I am not saying your engine guys are wrong about some blocks, just saying they are miss applying an old gen 1 issue to the gen 2 motor.
On The Tree
Joined: Jan 2004
Posts: 105
Likes: 1
I'd have a hard time believing there was any difference between the 2-bolt and 4-bolt LT1 blocks in terms of casting thickness. If that were the case I'd think everyone would be after the factory 4-bolt blocks (certainly those we need a block). Meh...
Those LSx iron blocks must be monsters - 6-bolt caps.
Those LSx iron blocks must be monsters - 6-bolt caps.
