3.8 or 4.1 cylinder wall thickness

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
Hi Guys,

I have a question for those that have sonic checked their stock blocks prior to using them. I'm interested to know what cylinder wall thickness you're seeing and what the bore size was. I've built a # of stock block engines over the years but have never sonic checked them. Anyone with actual #'s please give input.

Thanks

Neal
 

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
No one has sonic checked their block prior to using it? Where is Mr. Spool when you need him? Surely he and his crew sonic check all of their 1000 H.P. stock blocks.

Neal
 

ek02

Well-Known Member
Joined
Jan 31, 2008
My 484 casting 4.1 blocks have been an average of .250. The 291 4.1 blocks I have done are as thin as .130. They also have less material in the timing chain area. I have a late 140 , I think that's the number on it, 4.1 casting that checks out at .250. Weak main webs and cracking between the water passages and the bolt holes are the real problems on 4.1's.
 

BEATAV8

The Engine Whisperer
Joined
Feb 14, 2002
Something i snagged a while back
 

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750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
Thanks! This is good info. :cool: The reason I got into this is that I recently picked up an off center 4.1 block which is in nice shape but has a 4.060 bore. I'm sure the cylinders will be thin but was wondering how it compared to a stock block casting.

Neal
 

ek02

Well-Known Member
Joined
Jan 31, 2008
I saw the add for the off center. Those blocks were pretty thick. If the bores will clean up with a light hone and some custom pistons it should be ok. Those blocks are so hard to find without a pan rail that’s been repaired these days.
 

Mr.Spool

Well-Known Member
Joined
Nov 6, 2006
No one has sonic checked their block prior to using it? Where is Mr. Spool when you need him? Surely he and his crew sonic check all of their 1000 H.P. stock blocks.

Neal
Lol things get checked but the block still moves around alot.the engine builder has the final say in my world,I'm just the send it guys lol.the blocks aren't all the same but I have found that it still holds the power when other things are in place.i prefer to run a 3.8 stock stroke when I plan on really giving it the squeeze.prolonged hits above 150hp per hole will shorten her life.
 

750H.P.V6

Brutal 6 Racing
Joined
Sep 4, 2001
I saw the add for the off center. Those blocks were pretty thick. If the bores will clean up with a light hone and some custom pistons it should be ok. Those blocks are so hard to find without a pan rail that’s been repaired these days.
It's a clean block with no damage and it was in my neck of the woods so I bought it. Our machine shop had a sonic tester so I'll borrow that and see what the wall thickness is.

Neal
 

dank GN

BlackArts Automotive (661)993-8277
Joined
Jan 11, 2009
It's a clean block with no damage and it was in my neck of the woods so I bought it. Our machine shop had a sonic tester so I'll borrow that and see what the wall thickness is.

Neal
Yes I would be curious if you are talking about the block I ran down to you.
 

SCOOBY DOO

I'M NOT A MONSTER, I'M JUST AHEAD OF THE CURVE!!!
Joined
Feb 18, 2007
I'd tell everyone to stay as close to standard bore as possible. I had a .030 over 109 that cracked two different cylinders into the water jackets. I had the block sleeved twice and when it did it a 3rd time into another different cylinder I scrapped the block and went to a standard bore block.
 
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