Cylinder wall thickness

theman440 · 11-29-2017, 02:40 PM

A question for the engine builders here on CR - What would be a minimum cyl wall thickness you would want to see? The block is a factory Mopar 440 for a bracket car shootin for 700-750 hp.

Thank you

GTX JOHN · 12-01-2017, 04:46 AM

I would want .175 or more at finished overbore in a big block mopar or .135 in small block mopar.

theman440 · 12-01-2017, 07:16 PM

Thanks John,

Are you back in town? - you happen to have a sonic checker? call me I still need some wheels.

Paul Precht · 12-21-2017, 10:45 PM

The only blocks that are that are thick are the 413 industrial and motorhome, most 440s are less than .175" before boring and 700HP would be about the safe limit IMO. The aftermarket blocks are the way to go if you can get one. The 400 blocks are a bit stronger in the web area and more rigid due to the shorter cylinder length. A 400 block filled Halco machine grout and Pro-Gram Engineering main caps would be a good start.

Todd Gross · 12-28-2017, 07:52 AM

There were some thick blocks in 67-69 era. Back when I was more adventurous, we took some old blocks, filled them, bored/honed to 4.560 and put a 4.625 stroke to make an alcohol 604" It required a main girdle and good caps to hold things since the cylinder walls were at .060" +/- a little.
They didn't stay round very long as one might expect. That was back around 1990 and the only aftermarket blocks were KB. Thought it was worth a try. It wasn't.

GTX JOHN · 01-01-2018, 10:35 PM

We have seen thick and thin blocks......No matter what year
the 440 blocks are. Just have to check them.

SST3193 · 09-09-2020, 12:20 PM

I bought the 440 out of a 1971 New Yorker and it had the thickest cylinder walls, at about .220. That block also had water pump bosses cast into the back of the block, over the top of the bell. I assumed it was supposed to be a boat part.

Frank Castros · 11-25-2020, 06:59 PM

I have a friend who had a 426 NASCAR (Petty) Wedge block that was stupid thick on the thrust side. How many of those are out there.

11-29-2017, 02:40 PM	#1
theman440 Junior Member Join Date: Apr 2013 Location: Fabulous Las Vegas Posts: 97 Likes: 16 Liked 16 Times in 8 Posts	Cylinder wall thickness A question for the engine builders here on CR - What would be a minimum cyl wall thickness you would want to see? The block is a factory Mopar 440 for a bracket car shootin for 700-750 hp. Thank you __________________ Jeff Dudgeon '66 Coronet #10771 - bracket puke "the Flying Brick"

12-01-2017, 04:46 AM	#2
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 1,856 Likes: 955 Liked 849 Times in 255 Posts	Re: Cylinder wall thickness I would want .175 or more at finished overbore in a big block mopar or .135 in small block mopar. __________________ John Irving 741 Stock 741 Super Stock

12-01-2017, 07:16 PM	#3
theman440 Junior Member Join Date: Apr 2013 Location: Fabulous Las Vegas Posts: 97 Likes: 16 Liked 16 Times in 8 Posts	Re: Cylinder wall thickness Thanks John, Are you back in town? - you happen to have a sonic checker? call me I still need some wheels. __________________ Jeff Dudgeon '66 Coronet #10771 - bracket puke "the Flying Brick"

12-21-2017, 10:45 PM	#4
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 578 Likes: 99 Liked 57 Times in 24 Posts	Re: Cylinder wall thickness The only blocks that are that are thick are the 413 industrial and motorhome, most 440s are less than .175" before boring and 700HP would be about the safe limit IMO. The aftermarket blocks are the way to go if you can get one. The 400 blocks are a bit stronger in the web area and more rigid due to the shorter cylinder length. A 400 block filled Halco machine grout and Pro-Gram Engineering main caps would be a good start.

12-28-2017, 07:52 AM	#5
Todd Gross Member Join Date: Mar 2016 Location: Crete, IL Posts: 147 Likes: 131 Liked 34 Times in 15 Posts	Re: Cylinder wall thickness There were some thick blocks in 67-69 era. Back when I was more adventurous, we took some old blocks, filled them, bored/honed to 4.560 and put a 4.625 stroke to make an alcohol 604" It required a main girdle and good caps to hold things since the cylinder walls were at .060" +/- a little. They didn't stay round very long as one might expect. That was back around 1990 and the only aftermarket blocks were KB. Thought it was worth a try. It wasn't. __________________ Todd Gross

01-01-2018, 10:35 PM	#6
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 1,856 Likes: 955 Liked 849 Times in 255 Posts	Re: Cylinder wall thickness We have seen thick and thin blocks......No matter what year the 440 blocks are. Just have to check them. __________________ John Irving 741 Stock 741 Super Stock

09-09-2020, 12:20 PM	#7
SST3193 Junior Member Join Date: Oct 2009 Posts: 34 Likes: 1 Liked 2 Times in 2 Posts	Re: Cylinder wall thickness I bought the 440 out of a 1971 New Yorker and it had the thickest cylinder walls, at about .220. That block also had water pump bosses cast into the back of the block, over the top of the bell. I assumed it was supposed to be a boat part.

11-25-2020, 06:59 PM	#8
Frank Castros VIP Member Join Date: Nov 2001 Location: The Low Country Posts: 1,607 Likes: 756 Liked 605 Times in 226 Posts	Re: Cylinder wall thickness I have a friend who had a 426 NASCAR (Petty) Wedge block that was stupid thick on the thrust side. How many of those are out there.

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