400 Overbore question
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400 Overbore question
I am in the process of rebuilding my 400. I just found out that my cylinder walls have already been punched out once to .030 over, and have a good amount of wear on them. The machine shop said they dont think they can clean it up to run .040 over, and would be somewhere in the realm of .050-.060. I tried doing a search for safe overbore limits on the site, and on Google, and it came up dry.
I have always read that these engines shouldn't be bored over .030 to .040 at most.
And aside from that my Crank is toast along with 3 rods...
What are you thoughts?
I have found a few on CL for pretty cheap complete, but i don't know what the internal condition is like. Do i take a gamble on a whole new engine?
I have always read that these engines shouldn't be bored over .030 to .040 at most.
And aside from that my Crank is toast along with 3 rods...
What are you thoughts?
I have found a few on CL for pretty cheap complete, but i don't know what the internal condition is like. Do i take a gamble on a whole new engine?
Cargo Master
Joined: Apr 2010
Posts: 2,600
Likes: 64
From: Billings, MT
From what I've heard .040" is pushing it. If the shop doesn't have a sonic tester to check wall thickness on the thrust side, I'd find another block, or find a shop who can sonic check. Don't know where you are, but a buddy of mine has two 400 blocks that are good, one is already bored but not finish honed. In Montana
Laughing Gas
Joined: Jan 2006
Posts: 883
Likes: 7
From: New-brunswick,Canada
And aside from that my Crank is toast along with 3 rods...
[/QUOTE]
did the crank touch the rods or it's just the bearing ?
My block still have some small hole from rust after 30 over. had to sleeve the block on 3 cylinders. I ask if the sleeve were expensive they said about 20$ each so i said change it. What they never told me it was the time involve to replace them. 30 over job was 350$ with new cam bearing , frost plug and the color of my choice. i end up almost 1200$ Fu#$$#%$%!*%^! cker.
if it touch steel to steel, find a better block with better rotating assembly.
also visit TMeyer, Inc. Precision Automotive Machining
[/QUOTE]
did the crank touch the rods or it's just the bearing ?
My block still have some small hole from rust after 30 over. had to sleeve the block on 3 cylinders. I ask if the sleeve were expensive they said about 20$ each so i said change it. What they never told me it was the time involve to replace them. 30 over job was 350$ with new cam bearing , frost plug and the color of my choice. i end up almost 1200$ Fu#$$#%$%!*%^! cker.
if it touch steel to steel, find a better block with better rotating assembly.
also visit TMeyer, Inc. Precision Automotive Machining
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jlj6t
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
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Mar 13, 2021 08:44 PM
