360 blocks

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moparstud440

moparstud440

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Are the earlier/older 360 blocks better than the newer ones? I've heard that some of the 1st 360s were built using 340 cores thus resulting in thicker cylinder walls. Have and engine now that I'm certain has cracked on the backside of cylinder #8 and think the block is a early 80s but have to double check. Engine has 12:1 compression so maybe looking for another block. I know any block can be junk, but was going to try and source the "better" year blocks if there is such a thing.
 
There is (was) a 72 360 block for sale in the parts section. IIRC the 72 had the smaller 340 water jackets to take the 4.04 bore so it may (legend?) in fact have thicker cylinder walls.
 
So it is said but that isn’t the end all but a huge plus if you have thicker cylinder walls. The compression ratio isn’t a huge factor for cylinder wall thickness but more so the power being made. If anyone had any worry, a half fill of hard block is the answer.
 
I don’t know man. I like the late ‘80’s roller cam blocks better. The one I had Brian at IMM check out for me was good for a .070 over bore. So he built my 408 out of that block which cleaned up at a .020 over bore. They have taller lifter bores so not much work at all for a solid roller.
 
Yes the later blocks, lates 70's and early 80's are a crap shoot.

Any of the cyl walls can have cavitation...and that can lead to a cracked or pin hole cylinder that will give out and hydro the cyl walls out and send chunks everywhere destroying it all.
 
I probably have 10-13 (360) LA blocks. When it’s time to build a fresh engine I grab one, have it bored .030 and run it. I’ve gone as far as .040 but by then that block has served me well (after it’s worn out) I throw it on my scrap pile. I have a sonic checker and at those sizes I’ve never checked one.
 
I sonic tested a few and the best I had was a 76 casting, thicker than an early block I had.

I also tested several 318 blocks and they were also worse than the thinnest 360 I had tested.
 
Block is a 1977 and has about a 2" crack in #8 cylinder. My dad has ran Mopars all his life. Was mainly a BB guy til about 15 years or so ago. He and I have assembled atleast half dozen 360 and this is the 1st block issue we've had. Also happen to be the 1st stroker he built to. On the bright side issue was found so just need to get another block, could have scattered on the track and cost a whole lot more $$.
 
moparstud440 said:
Block is a 1977 and has about a 2" crack in #8 cylinder. My dad has ran Mopars all his life. Was mainly a BB guy til about 15 years or so ago. He and I have assembled atleast half dozen 360 and this is the 1st block issue we've had. Also happen to be the 1st stroker he built to. On the bright side issue was found so just need to get another block, could have scattered on the track and cost a whole lot more $$.
Click to expand...
Check rod clearance to bottom of bore.

If the clearance isn't enough, the slightest bit of crank torsioning can cause interference and crack the cyl at the bottom. It sometimes goes around then up...and at high rpm the cyl falls out. The blocks heat expansion needs to be considered too.
 
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moparstud440 said:
Block is a 1977 and has about a 2" crack in #8 cylinder. My dad has ran Mopars all his life. Was mainly a BB guy til about 15 years or so ago. He and I have assembled atleast half dozen 360 and this is the 1st block issue we've had. Also happen to be the 1st stroker he built to. On the bright side issue was found so just need to get another block, could have scattered on the track and cost a whole lot more $$.
Click to expand...


Why not sleeve the crack and use the block?
 
Only one absolute way to know
( SONIC TEST ) cheap insurance
If u have multiple blocks have them checked hopefully the first one is what u seek !!

20210728_001457.jpg
 
The answer is sorta. You have a greater chance of getting a thicker block with the early ones, but nothing's set on stone. Since over boring is really not the way to make power, it's really a moot point anyway.
 
I personally worry about core shift more than year casting. If doing a roller, grinding the lifter valley is a crap shoot. So to me, a roller block would carry more weight for me than a certain year casting.
 
Caco2120 said:
I personally worry about core shift more than year casting. If doing a roller, grinding the lifter valley is a crap shoot. So to me, a roller block would carry more weight for me than a certain year casting.
Click to expand...

Right and thing about it, casting methods only improved over the years, so the later blocks are generally better as far as not having a lot of core shift. Even though the earlier blocks can be thicker, they sometimes suffer from core shift worse than the later blocks. That's why it's always best to get them sonic tested so you know what you have.
 
I have an 80 block that is bored .060 and is 4"stroke. It's has been in my racecar it's entire life. Started out at 11.5 and now is 12.5.
 
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