What is the refrence of "Magnum"

[GT_My_way]

I noticed a lot of people refering to magnum heads and magnum blocks. What are they and how can you tell them apart. the block I have is a 71 340 x heads. thanks

 

[snowymountainman]

Magnum block/heads are the small blocks that were manufactured after 1991. I'm not real sure on that year but the really easy way to tell them apart is by the number of bolts holding the valve covers. LA style engines have 5 bolts (3 on bottom, two on the top). Magnums have 6 or 10 bolts (I think!! Haven't seen one in ages!! ) on each valve cover.

Here's a cut/paste from Allpar.com

The main differences to the "new" 5.2l and the "old" 318 are in the block and heads. The new block affords roller lifters, yes it has changed lifter agle for same, and has bosses for the lifter retainers. The heads are high-swirl / high-flow heads, though not the old "X" heads of the 340, and obviously the Magnum has that cool intake. the "new" 5.2l came about in changes made in '87, which were fully incorporated by '90. The changes were made to facilitate a more common creation of both the 5.2 and 3.9 engines.

The "Next Generation" V8 family produces similar power with less weight, fuel use, and emissions, though durability is unknown. I'll miss the LA family's low-end grunt and long life, but the new engines seem to rev more freely, are more efficient, and may be as bulletproof.
Gary Howell wrote: "The Magnum 318 and 360 engines are LA engines with different cylinder heads. The blocks are physically the same as the earlier LA engines, except the oil passage for the shaft mounted rockers is not drilled, because the Magnum engines oil through the push rods. The boss is there if you need to use the old style heads."

 

[AdamR]

Yup Magnums are late model V6 and V8s. The heads flow better then the earlier version and have a better combution chamber. They are also Hyd. roller cams.

These are the same motors that Mopar Perf. uses for the crate motors.

Hows 380 horse power with just an intake and cam swap sound ?