Magnum vs LA compatibility

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matt030305

matt030305

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Hey FABO techs, I was wondering on the part compatibility on magnum engines vs LA engines. I recently had a 340 block crack on me and now have a bunch of top end parts made specifically for an LA block. I’m contemplating if I should build a 340 based 416 Stroker or a 360 based 408 Stroker. 360s are more abundant and I’ve heard that the magnum blocks can handle more power as well. Since I have a bunch of top end parts made specifically for my LA block, Here is the list of parts:

-trickflow 190 heads with hydraulic roller springs (supports lift up to .680)
-edelbrock air gap intake for LA block
-morrel hydraulic roller lifters
-Harland sharp 1.6 roller rockers made to support LA block oil thru pushrods

I know I have change the intake since the bolt pattern for the magnum block is different, lifters since magnum blocks came standard with roller lifters.

My question is: should I return my roller rockers since Magnum blocks have a different oiling system? And is there anything else I need to replace? Thanks!
 
The intake has to match the heads, not the block, so if you have Trick flow heads and an LA pattern intake those match and can be used on a Magnum block.

Double check your rocker arm part numbers. If they have the oil through pushrods provision they can be used with your Trick Flow heads on a Magnum block. If they were LA style without the oil through pushrod provisions you need different rocker arms.

You can run the factory Magnum hydraulic roller lifters with a new hydraulic roller camshaft for either LA or Magnum.

I do not know if the LA retrofit hydraulic roller lifters will fit a Magnum block because I never tried it yet. The top of the lifter bores on a Magnum block are a little taller than an LA block.
 
Personally, I love the 340 as is and would never stroke that one. I'd put the stroker in a 360 or a magnum 360. If I wanted to use roller lifters I'd use the magnum. I'm in the same situation and have a couple 340's and a 360 police motor and a magnum and that's the plan I came up with.
 
If your just using the magnum block only the main difference is the rocker oiling, magnums oil through the roller lifters, some have the LA style oiling holes too on the deck most don't but probably could get a machine shop drill them if you wished. And the Deck height is slightly shorter from what I hear. Other than that it's basically a roller LA 360 block.

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Like has allready been pointed out before, AND in your other thread, with the parts you have, you can put your top end on the magnum block, zero issues
 
NC Engine Builder said:
Like has allready been pointed out before, AND in your other thread, with the parts you have, you can put your top end on the magnum block, zero issues
Click to expand...
...and you can put the LA front end on the Magnum. I wanted my 5.9 to look as much like an LA as possible so I used my LA timing cover, water pump, v-belt pulleys, and fan.
 
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