LA blocks

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63SplitWindow said:
Other than the cam and lifters, are there any other differences from the older LA blocks?
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Well yeah. The main bore diameters from the 273, 318, 340 from the 360. Also the bore sizes. Some blocks have more meat than others in various places.
 
"It's been said" that the early 360 blocks had more meat around the cylinders due to the factory still using 340 water jacket cores when they cast the 360 blocks the first couple years. More dimensionally stable, and possible bigger overbore- but you'd still need to have it checked to confirm a big bore.
Roller blocks, other than a slightly different valley configuration to accommodate the lifter retaining spider, also had taller lifter bores; which can be helpful in keeping some lifters from exposing their oil grooves with high lift HFT cams or with some aftermarket retrofit roller lifters.
 
Professor Fate said:
"It's been said" that the early 360 blocks had more meat around the cylinders due to the factory still using 340 water jacket cores when they cast the 360 blocks the first couple years. More dimensionally stable, and possible bigger overbore- but you'd still need to have it checked to confirm a big bore.
Roller blocks, other than a slightly different valley configuration to accommodate the lifter retaining spider, also had taller lifter bores; which can be helpful in keeping some lifters from exposing their oil grooves with high lift cams or with some aftermarket retrofit roller lifters.
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ok.....thanks Professor
 
I can’t 100% verify but magnum blocks are said to have a lower deck height spec. They have more meat in the pan rail as well. Not sure if those carry over to the roller LAs.
 
63SplitWindow said:
basically, I want to know which would be the better choice (if any) for a 360 stroker build
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I'm biased to old non roller 360. I have a 1975 360 block in my dart sport and it runs well. I make sure to use higher zinc oil to help cam survive. I like to keep all the drivetrain as it would be in its era. But everyone is open to their way of doing things too. I believe a non roller is just as good as a roller LA. I don't like magnum LA's because of the Chevy style rocker set up. I prefer shaft rockers.
 
QuickDart360 said:
I'm biased to old non roller 360. I have a 1975 360 block in my dart sport and it runs well. I make sure to use higher zinc oil to help cam survive. I like to keep all the drivetrain as it would be in its era. But everyone is open to their way of doing things too. I believe a non roller is just as good as a roller LA. I don't like magnum LA's because of the Chevy style rocker set up. I prefer shaft rockers.
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Understood
 
Early 71-74 were stronger and sought after when building a stroker 360. They had much thicker cylinder walls. The blocks were much stiffer. Most engine builders years back were always looking for Casting date 1970-1972. I was selling them for double of other years. especially the low pour numbers. 360-1 1970 were golden.
 
63SplitWindow said:
Is there any availability issues with the choice of roller cams for the LA roller blocks?
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Any of the retrofit LA roller cams will work in the roller block, although with the factory retainer you are limited to factory-type hydraulic roller lifters. I am not aware of anybody making a solid roller lifter that works with the factory spider.
Magnum roller cams will also work if you don't need to run a fuel pump eccentric, and take into account the difference in rocker ratios when you select your cam specs (LA-1.5:1, Magnum-1.6:1).
 
Has anyone ever weighed the different LA blocks (preferably virgin) to perhaps get a hint of how much metal difference each has or have the resources? (early 360, late 360, '80s pre roller, roller blocks & Magnum) Add sonic testing the cylinder walls and a clearer picture may emerge. (Preferably with the same scale & test tools to eliminate calibration variances.)
 
Only the first couple years of the Magnum block has the hole drilled for rocker shaft oiling. Run the magnum with their heads and you’re gonna be oiling through the push rods.

If you’re using aftermarket heads, most use oiling through the head.
Your course can use oiling through the push rods on the LA heads but you need the proper rockers and the good ones to run about seven $800 for a set.
 
Locomotion said:
Has anyone ever weighed the different LA blocks (preferably virgin) to perhaps get a hint of how much metal difference each has or have the resources? (early 360, late 360, '80s pre roller, roller blocks & Magnum) Add sonic testing the cylinder walls and a clearer picture may emerge. (Preferably with the same scale & test tools to eliminate calibration variances.)
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I never did a weight or cylinder wall thickness comparison with another block but when I built my 408 I used a 360 block dated march 73 and had it sonic tested and my machinist said it had some of the thickest cylinder walls he'd seen and he'd been testing them for 40 yrs. It's been over 12 years so I don't remember the exact thickness of the walls but he said if I had wanted to bore it .070 over (to use .030 over 340 pistons) it would've been fine. Since it wasn't a race application I just went .030 over. Hope this helps
 
The thing is, the MOST important issue is the thinnest area in any given bore. Doesn't matter how thick 7 cylinders are if one is thin. The old blocks are over 50 years old, and corrosion inside the water jackets takes its toll. And the old claim about "much thicker" cylinders is greatly exaggerated. Even if they used "340" water jackets, that would only be .040 difference, or .020 per side. Big deal.
 
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