Early LA 360 Blocks
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abodyjoe
Well-Known Member
i say go 89-up 360 la block. they are set up for a roller set up.
moper
Well-Known Member
Do a search. It's be hashed and re-hashed several times, and opinions vary as greatly as the facts.
My short, short version... No advantage to an earlier block, and as Joe says, if a hydraulic roller cam is what you want, it's cheaper to start with an 89-91 roller LA 360 block.
My short, short version... No advantage to an earlier block, and as Joe says, if a hydraulic roller cam is what you want, it's cheaper to start with an 89-91 roller LA 360 block.
K Will do thanks. Was interested in other than the obvious.
Block strength, cyl thickness, overbore capacity (CAN it go to 4.1 like a 340?) not so concerned about ability to go roller as am very happy with my solid flat cust grinds, and drop in rlr lifters have been avail for some time.
Would like updated info from those that actually HAVE and are running the early blocks, esp in 400+" apps.
Already have a few of them, so expense of obtaining isnt an issue.
Thanks
Block strength, cyl thickness, overbore capacity (CAN it go to 4.1 like a 340?) not so concerned about ability to go roller as am very happy with my solid flat cust grinds, and drop in rlr lifters have been avail for some time.
Would like updated info from those that actually HAVE and are running the early blocks, esp in 400+" apps.
Already have a few of them, so expense of obtaining isnt an issue.
Thanks
Snake
Mopar Nut
I have an 86 360 block punch 20 over with no issues.
abodyjoe
Well-Known Member
well you seem to already have all the answers so do what you want.
MRL Performance
Well-Known Member
Magnum blocks are the best. They have less core shift and have a much better oiling system than the older blocks(larger passages and relief cuts on the main oiling at the bearing). I have sonic tested hundreds of blocks and they almost always come out great.
Something intellegent, preferably from actual hands on experience, that a more experienced engine builder than myself would know. But thank you for your ingenious answer to my rlr cam ?
MRL--Thank you. That does help. Is there enough material in the early block to modify it to magnum oiling capacity? The mag appears to have larger main web supports also, is this due to difference in metal strength/composition vs the early? And are the lower cyls less likely to crack in the early block in higher hp stroker apps without block filler vs the mags?
Ok. Here's my actual hands on experience. Let the war begin, but I have CONFIRMED it over and over and it is very easy to confirm for yourself. The 71-73 360 does indeed have thicker walls and you don't need a sonic tester or a bore thickness gauge to tell. Know what you need? Your eyes. All you have to do is pop a freeze plug out from between two cylinders on an early block and a late block. Compare the distance between the cylinders between the two and you will see a big difference. People can talk and argue and blow smoke and bullshit all day long about it, but that is the FACT about it. Look for yourself if you don't believe me.
Strkrscmp: Hale Yeeea! Thats what i want to hear. I have no blocks past 73 left in my collection to compare an early to. Only 340s and early 360s. Was sure someone had already done this, but didnt want to read thru a bunch of condescending juvenile bs to get to it. 
Higher nickel in the early? My machinist gripes whenever i bring an early to be bored/decked/mains resized.
Due to better metal or just old and seasoned?
File test on mag/vs early: mag cuts like butter, early is one hard sob.
Higher nickel in the early? My machinist gripes whenever i bring an early to be bored/decked/mains resized.
Due to better metal or just old and seasoned?
File test on mag/vs early: mag cuts like butter, early is one hard sob.
I don't know about the high nickle blah blah, but I do know about the other. I have personally bored 3 early 70s 360 blocks .100 over and one 1977 360 block .070 over. People get confused when talkin about cylinder thickness because they forget to divide by two. When makin calculations for cylinder bores, you have to consider the other side of the cylinder. lol I know plenty of guys around here who've gone to 4" with 318s. A LOT of them. At first thought, you think ****, that's .090" over....and it is...........but you're only taking .045" off each side. That kinda tells you the real deal. Most 318s will go that far...and truth be told there's probably room for a .030" over from there. ....now watch the flamin. LOL
Mad Dart
Nothing to see Here!
I don't see why you would need a newer 360 block because you want it set up for a roller cam, maybe if you want a rollered stock engine other than that who cares. The op is talking about 400+ CI, the new Roller Lifters take the guess work out of the equation when going roller cam. The block I used for my latest build is a 1973 360, it passed sonic test no problem and I used Brians solid roller lifters that drop right in. The LA valve train is way more stable than the Stud mount of the magnum set up. Mine is now 410 CI of Twin Turbo Small Block Mopar!
MD: nice. Did you o ring or check deck thickness? If so was it +/- the published .500 average?
Yes, i do have my own opinions & theory's, but what good are they if they cant be tested, and or put up to others. Wether they be like minded or not.
Yes, i do have my own opinions & theory's, but what good are they if they cant be tested, and or put up to others. Wether they be like minded or not.
Mad Dart
Nothing to see Here!
Brian at IMM did all the machining. It was decked, mains line honed with studs etc, I also had him line hone the cam journals which made a huge difference. With the pan off you can grab a counter weight and spin the engine with ease. It's the nicest rotating engine I have built to date. No I did not o ring it, I used Cometic MLS Head Gaskets and ARP head studs, the heads and the block were milled for them nice and smooth. I also used copper coat on the gaskets right before installation.
moper
Well-Known Member
Strkrscmp: Hale Yeeea! Thats what i want to hear. I have no blocks past 73 left in my collection to compare an early to. Only 340s and early 360s. Was sure someone had already done this, but didnt want to read thru a bunch of condescending juvenile bs to get to it.
Higher nickel in the early? My machinist gripes whenever i bring an early to be bored/decked/mains resized.
Due to better metal or just old and seasoned?
File test on mag/vs early: mag cuts like butter, early is one hard sob.
Condescending juvenile bullshit? Thanks.
And this is.....
and this is... I spliced it together for you.
pot or kettle???
I'll sit back, watch the fun.
enjoy the ride.
moper
Well-Known Member
That was me suggesting you to do a search, where there are in depth facts by me and others for you to read through. I apologize but I can't see how you define that as condescending. You said have your own ideas on the subject and perhaps you are simply receiving the info from the position of "prove me wrong". I don;t care if you believe me or not. I generally just try to help. There is a lot more misinformation than fact on this subject because not everyone has the experience over the decades, the right equipment, connections, or knows how to use it properly. That's not a condescending opinion on my part. It's just what I've found over time. It's also not a problem for anyone who wants to add to the discussion to do so, regardless of thier background. Now so you don't have to do the search... Here's some truths I've found over the years:
Concerning 360 LAs -
Truth - they are cast of a better quality iron. "High nickel" is a term usually reserved for GM or Ford because historically they use softer iron for production blocks than Chrysler. Studebaker has the highest nickel content and hardest blocks I know of in a gas engine...
Truth - The first year LA 360s were cast using the 340 cylinder cores. This was a simple idea to use existing materials on the "new for 71" engine. The resulting smaller bore means they theoretically have thicker walls. This was changed for 1972, my guess is to use less iron in each casting.
Truth - Mopar's casting quality sucked. It sucked for everything, all displacements, right up to the Magnums. So the fact they used a 340 core, and good iron, didn't stop that core from shifting when they were poured.
Truth - Using a good certified sonic tester, on more than a few blocks, is the only way to find these details out for yourself. I happened to buy my own good one, and paid to have them train me on how to use it. I have tested for shops, racers, customers of mine, and friends locally for 9 years now. I've tested a variety of makes, but I've been building only Mopars since the mid 80s.
Truth - In the mid 70s Chrysler changed to a low quality iron. I believe it was around 1977 but that's info supplied to me by a shop that was rockwell testing various year blocks for a circle track program they have so call the year en estimate. Around the same time as this material change was made, the blocks seem to have gotten generally thicker in the major and minor thrust, when not affected by core shift. This is true from later 70s to the Magnums. A point of interest on what MRL posted... The Magnums have the larger main feeds, but so do the later roller 80s-91 LA 360s. As far as mods, enlarging the main feeds only requires a long drill bit and a steady hand. I do it on all the builds I do.
Truth - Visual inspection of any kind is only as good as the eye and the lighting. Sorry to disagree with Stroker but anyone that knows about castings or machining will tell you your eyes are the last thing to use to test. This would be why I also own a magnufluxing setup and why the better sonic testers are certified.
Truth - The most consistently well-cast 360 blocks I've tested are the 89-up 360s. I have not tested many Magnums. Only one, which was on par with the later LA 360s, so I'd agree with MRL there. As a point of interest, the best 340 blocks seem to be the 72-73, not the earlier ones.
Truth - The fact that the factory wanted a certain result has little influence on the production quality. This is also true for the "230" 400 B wedge blocks that were actually supposed to be thicker... but still suffer from core shift. Just like the early MP Hemi and RB blocks, and the early production 59° MP small blocks that were unable to go more than std bore. I have several 422s running around in blocks that went .060 over and had meat left over. I've also seen stock 340s that needed sleeves due to cooling jacket rust that caused pitting and thin spots that were thinner than .070" at std bore and a little wear. I've had numerous blocks that got one or two sleeves to make them passable. That's because 40 years of use, the elements, and foundry's lack of quality control created thier own truths regardless of the intent of the engineers.
Concerning 360 LAs -
Truth - they are cast of a better quality iron. "High nickel" is a term usually reserved for GM or Ford because historically they use softer iron for production blocks than Chrysler. Studebaker has the highest nickel content and hardest blocks I know of in a gas engine...
Truth - The first year LA 360s were cast using the 340 cylinder cores. This was a simple idea to use existing materials on the "new for 71" engine. The resulting smaller bore means they theoretically have thicker walls. This was changed for 1972, my guess is to use less iron in each casting.
Truth - Mopar's casting quality sucked. It sucked for everything, all displacements, right up to the Magnums. So the fact they used a 340 core, and good iron, didn't stop that core from shifting when they were poured.
Truth - Using a good certified sonic tester, on more than a few blocks, is the only way to find these details out for yourself. I happened to buy my own good one, and paid to have them train me on how to use it. I have tested for shops, racers, customers of mine, and friends locally for 9 years now. I've tested a variety of makes, but I've been building only Mopars since the mid 80s.
Truth - In the mid 70s Chrysler changed to a low quality iron. I believe it was around 1977 but that's info supplied to me by a shop that was rockwell testing various year blocks for a circle track program they have so call the year en estimate. Around the same time as this material change was made, the blocks seem to have gotten generally thicker in the major and minor thrust, when not affected by core shift. This is true from later 70s to the Magnums. A point of interest on what MRL posted... The Magnums have the larger main feeds, but so do the later roller 80s-91 LA 360s. As far as mods, enlarging the main feeds only requires a long drill bit and a steady hand. I do it on all the builds I do.
Truth - Visual inspection of any kind is only as good as the eye and the lighting. Sorry to disagree with Stroker but anyone that knows about castings or machining will tell you your eyes are the last thing to use to test. This would be why I also own a magnufluxing setup and why the better sonic testers are certified.
Truth - The most consistently well-cast 360 blocks I've tested are the 89-up 360s. I have not tested many Magnums. Only one, which was on par with the later LA 360s, so I'd agree with MRL there. As a point of interest, the best 340 blocks seem to be the 72-73, not the earlier ones.
Truth - The fact that the factory wanted a certain result has little influence on the production quality. This is also true for the "230" 400 B wedge blocks that were actually supposed to be thicker... but still suffer from core shift. Just like the early MP Hemi and RB blocks, and the early production 59° MP small blocks that were unable to go more than std bore. I have several 422s running around in blocks that went .060 over and had meat left over. I've also seen stock 340s that needed sleeves due to cooling jacket rust that caused pitting and thin spots that were thinner than .070" at std bore and a little wear. I've had numerous blocks that got one or two sleeves to make them passable. That's because 40 years of use, the elements, and foundry's lack of quality control created thier own truths regardless of the intent of the engineers.
moper, we don't disagree......I have always said the BEST thing is to sonic check. ....but don't drag me into this. LOL
airwoofer
Drivetrain limit explorer
How bad is it if a cyl is sleeved? My stroker (73 340 block) has one cyl sleeved.
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