Magnum vs LA compatibility

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.