360's

[twodko]

What's the difference between LA and magnum 360 small block
crate motors?

Which is more desirable for a street machine?

[68X426]

I may be wrong, but I thought that they are essentially the same block and heads, but with the Magnum having more "modern" internal components.

I'd say a Magnum crate would be the choice, what with EFI and the availability of performance upgrades.

Looking at a Dart roller and wanting to add your own motor?

[TUFCAT]

What's the difference between LA and magnum 360 small block
crate motors?

The first visual difference most people notice is the intake - which looks like the side of a beer keg. The valve covers are rectangular shaped, and the water pump/timing chain covers is unique to this family.....along with a serpentine belt system and (not so obvious) crank sensor.

Internally, Magnum engines use roller camshafts. The heads also changed valve sizes and use different ratio rocker arms without rocker shafts. There's no exhaust crossover in the heads.  

The lower end of the magnum was kept pretty much the same as the LA,  but top end parts are not interchangeable between the two families.

[Troy]

The biggest difference in the engines are the heads. Magnums flow really well! Since the heads are different the intakes aren't interchangeable (different bolt pattern). Later Magnums were all roller cammed from the factory. I believe all were fuel injected. Due to the FI, a mechanical fuel pump wasn't necessary so the timing cover and most of the other stuff on the front end is different. This is all interchangeable with the LA stuff though.

Troy

[twodko]

Thanks for all the input gentlemen.
I'm leaning toward an LA motor only because
I think a shaft based valve lifter arrangement
is stronger.

I'm going to recon a '73 Dart Swinger today.
Red with black interior & VT. 318 auto driver. A buddy
is riding shotgun in case I buy the car.
Low 4 figure pricing is more palatable for me
than low 5 figure pricing.
I'll post the link toot sweet.......stand by........

[twodko]

This listing is on SF Bay Area CL. Car is in Concord.
It's had some left front fender damage and needs a new
front bumper but appears to be in great shape otherwise
according the owner. I hope that is indeed the case.

More to follow after a look see today.

[Troy]

I should mention a Magnum "crate" has all the LA components on the outside and, usually, a carb intake so it drops right in place of an LA in an older car.

Troy

[TUFCAT]

Sorry for the bad information guys!    ...and thanks to Troy for the clarification.  I should do better research before spewing bad information!  

After I quick tour on Moparts I learned Magnum heads are interchangeable with LA engines. Many do it for the closed chamber design, better breathing, and swirl characteristics.

Its not a "direct" swap - but its fairly easy.  Since rocker arms are no longer used, replacement oil fed pushrods and lifters are required. Additionally, intake bolts don't line up to the old LA intake... (bolts go into the heads at different angles).  This is no longer a problem since Mopar Performance makes an intake to facilitate mounting your favorite 4bbl to a Magnum headed LA engine.  

The valve covers are 10-bolt instead of 5 bolt so they'll look different.  No way around that.  

Since all Magnums used electric fuel pumps, a Magnum engine swap also has unique fuel pump considerations.....(it's a mounting issue). If you don't want to convert to electric, most threads said it was just a matter of swapping in the LA cam, and using the LA engine front timing chain cover.

Sorry for being wrong....   Like I said, I should done better research on this.  

[twodko]

No worries Tuffy, you always give sage advise. Besides who doesn't
trust a "I'd hit that" fellow MOPAR guy? If you're not already ex-navy you
would have been a great squid! 

In other news.....

The '70 Dart Swinger I looked at today was a pig with lipstick.