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max overbore on a 72 400 block #873190 12/06/10 09:01 PM 12/06/10 09:01 PM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	sonic checking showed i have a good standard bore 400 block(.369top,.374middle,.376bottom). all bores read the same. how many thou needs to be left in cylinder wall after being bored as a minumum? thinking about boring.060 to clean up enough,but would like some left for future use. thanks http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873191 12/06/10 09:10 PM 12/06/10 09:10 PM
Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY H hemigod426 top fuel
hemigod426 top fuel H Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY	id start with .040 over pistons, then have 40-60 room later. ive put .30 over boring cutters in 400 blocks that were so out of wack it would not hit all the way around the bore. fill it with block filler only up to soft plug bottoms only and bore away. if it wont clean up at 40 id get another block, or if you have the 60 over pistons now go with that block and some filler. MOPAR OR NO CAR

Re: max overbore on a 72 400 block [Re: hemigod426] #873192 12/06/10 09:23 PM 12/06/10 09:23 PM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	ok,but whats the minimum allowable thickness? the 400 lost a rod and damaged one cylinder. the guy that checked it sugested having it sleeved. it does'nt look that bad to me,just beat up on the bottom of the cylinder. i can't see with the naked eye,but he said their where some holes in the cylinder wall only seen with the magni flux. i thought maybe a .060 over bore would be enough to clean this up. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873193 12/06/10 09:34 PM 12/06/10 09:34 PM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	They appear to be pretty good #s , IIRC .250 thrust side is good...............gotta take advantage here , take her out .090" with a 4.5 crank , 554 CUBES. Last edited by 602heavy; 12/06/10 09:37 PM.

Re: max overbore on a 72 400 block [Re: 602heavy] #873194 12/06/10 10:07 PM 12/06/10 10:07 PM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	so .250 thrust side is the minumum? if so that leaves me .119 max. at that rate i could go .060 no problem. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873195 12/06/10 10:11 PM 12/06/10 10:11 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	If you need the .060 to get clean up go for it. Otherwise, I'd go minimum. I had a stock 400 clean up at .020 over and that's what I ran. Even though thickness sounds OK, thicker is always better if/when you need to freshen it later. Plus stiff cylinder walls help power.

Re: max overbore on a 72 400 block [Re: ahy] #873196 12/06/10 10:17 PM 12/06/10 10:17 PM
Joined: Aug 2006 Posts: 614 Michigan G Get-X mopar
Get-X mopar G Joined: Aug 2006 Posts: 614 Michigan	I've seen a lot less than .250 in the major thrust without any trouble. Those sonic numbers seem crazy good to me. '65 Belvedere '68 GTX '57 Dodge pickup

Re: max overbore on a 72 400 block [Re: ahy] #873197 12/06/10 10:17 PM 12/06/10 10:17 PM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	only lookin to build a 499/505. the 4.375 bore seems to be the best for off shelf piston selection and the 4.150 stroke would be easier on thrust side. should last a long time with 6500 shift points. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873198 12/06/10 10:25 PM 12/06/10 10:25 PM
Joined: Aug 2003 Posts: 43,259 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,259 Bend,OR USA	Quote: sonic checking showed i have a good standard bore 400 block(.369top,.374middle,.376bottom). all bores read the same. how many thou needs to be left in cylinder wall after being bored as a minumum? thinking about boring.060 to clean up enough,but would like some left for future use. thanks That is a exceptional block The best 400 block I've seen(12 to 15 only) had no more than .250 thick in the major thrust side and then had less than .190 on the minor thrust sides, some as thin as .120 If you decide to sleeve the bad cylinder in your old block ask the shop to use a ductile iron sleeve, have them install it before doing any other work and then pressure test the block on the side that has the sleeve before doing any thing else to the block Don't ask why I'm suggesting that If your machine shop does not know how to install a sleeve in a block without distorting the cylinder walls next to the sleeved cylinder have them bore it to the next oversize you can get piston rings for after installing the new sleeve Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: max overbore on a 72 400 block [Re: mopar dave] #873199 12/06/10 10:30 PM 12/06/10 10:30 PM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	Quote: the 4.150 stroke would be easier on thrust side. should last a long time With those numbers i'd have no worries going 4.750" stroke using a tiny rod. .....0.250 thrust (pas side) is not considered the 'minimum' , some blocks out there are considered good @ .190 , you have a very good block sitting there regards cylinder wall thickness , saddle area may be something else to look at. Last edited by 602heavy; 12/06/10 10:31 PM.

Re: max overbore on a 72 400 block [Re: mopar dave] #873200 12/06/10 11:18 PM 12/06/10 11:18 PM
Joined: Jan 2003 Posts: 6,591 Canton, Ohio S Sport440 master
Sport440 master S Joined: Jan 2003 Posts: 6,591 Canton, Ohio	Id be very suspect of those numbers. Especially when you state all bores the Same Whats the non thrust sides measure .020 Idont mean to rain on your parade but something doesnt seem right. Id hate for you to proceed with a build if the numbers might not be correct. mike

Re: max overbore on a 72 400 block [Re: Sport440] #873201 12/07/10 12:11 AM 12/07/10 12:11 AM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	its either the same or he only measured the thrust side,but what would it matter. would'nt the thrust side be more important anyway? http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873202 12/07/10 12:17 AM 12/07/10 12:17 AM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	cylinder 1 is the same as cylinder 2 and 3 is same as 4, 5 same as 6 and 7 same as 8. 1,3,5,7 have different numbers,but each matches the bore on opposite side of block. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873203 12/07/10 12:32 AM 12/07/10 12:32 AM
Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY H hemigod426 top fuel
hemigod426 top fuel H Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY	Quote: ok,but whats the minimum allowable thickness? the 400 lost a rod and damaged one cylinder. the guy that checked it sugested having it sleeved. it does'nt look that bad to me,just beat up on the bottom of the cylinder. i can't see with the naked eye,but he said their where some holes in the cylinder wall only seen with the magni flux. i thought maybe a .060 over bore would be enough to clean this up. after reading that, id make sure not cracked in main webbing. and when you say holes in bottom cylinder, id have it pressure tested to make sure bore is not cracked to water passage. what are your plans for motor, if you say racey at all ill say sleeve it, or get another block MOPAR OR NO CAR

Re: max overbore on a 72 400 block [Re: hemigod426] #873204 12/07/10 12:34 AM 12/07/10 12:34 AM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	lookin to make 700-750hp with it. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873205 12/07/10 12:37 AM 12/07/10 12:37 AM
Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY H hemigod426 top fuel
hemigod426 top fuel H Joined: Feb 2007 Posts: 2,315 MOPAR HEADQUARTERS IN ALDEN NY	Quote: lookin to make 700-750hp with it. [8 sleeves and block filler short pour/quote] MOPAR OR NO CAR

Re: max overbore on a 72 400 block [Re: Sport440] #873206 12/07/10 12:41 AM 12/07/10 12:41 AM
Joined: May 2008 Posts: 1,131 Thigh-Gap Junction @ @#$%&*! New user name, Same old jerk!
@#$%&*! New user name, Same old jerk! @ Joined: May 2008 Posts: 1,131 Thigh-Gap Junction	Quote: Id be very suspect of those numbers. Especially when you state all bores the Same I doubt the accuracy and usefulness of the numbers you were given. Sorry.

Re: max overbore on a 72 400 block [Re: @#$%&*!] #873207 12/07/10 12:49 AM 12/07/10 12:49 AM
Joined: Aug 2003 Posts: 8,716 Baltimore/Denver 64Post master
64Post master Joined: Aug 2003 Posts: 8,716 Baltimore/Denver	Quote: Quote: Id be very suspect of those numbers. Especially when you state all bores the Same I doubt the accuracy and usefulness of the numbers you were given. Sorry. X3 Silly question: Is there heavy scale in the jackets? Was the block tanked/scaled before measuring?

Re: max overbore on a 72 400 block [Re: 64Post] #873208 12/07/10 12:55 AM 12/07/10 12:55 AM
Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,043 Mt Morris Michigan	the block has not been tanked yet. wanted to get it mag'ed and sonic checked first. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: max overbore on a 72 400 block [Re: mopar dave] #873209 12/07/10 01:06 AM 12/07/10 01:06 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Those are some SUPER good numbers... I would take it to another shop to have it tested... the guy I take my blocks to gives me a PILE FULL of numbers, 64 readings per cylinder for $70... I have never heard of cyl being that equal... would be nice if it is

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