What parts do i need in doing a 302 into a 5.0L HO????

Let's figure out what you have before we get too deep in this...

This doesn’t prove that the block is HO. Some trucks evidently use a HO firing order
with a low lift cam. However, it will definitely prove that a block can’t be HO because the firing order is wrong.

Remove the #1 & #3 spark plugs. Put your finger in #1 spark plug hole. Crank the engine over until you feel compression on #1 cylinder. Slowly turn the engine until the TDC mark and the timing pointer line up. Mark TDC on the balancer with chalk or paint. Put your finger in #3 spark plug hole and crank the engine 90 degrees. You should feel pressure trying to blow past your finger. If you do not feel pressure, repeat the process again. If you feel pressure, it is a HO engine.

No pressure the second time, remove spark plug #5. Put your finger in #1 spark plug hole. Crank the engine over until you feel compression on #1 cylinder. Put your finger in #5 spark plug hole and crank the engine 90 degrees. If you feel pressure now, the engine is not a HO model, no matter what it says on the engine.

Using a small carpenter or machinist square to mark the harmonic balancer off into 90 degree sections may be helpful here.

A 15/16 deep socket & breaker bar or ratchet may be used to turn the engine.

The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8



Now that we know if the block uses the standard firing order, here's the next step.

The camshaft and computer for a HO 5.0 are different from the standard 5.0. Do not attempt to move
the fuel injector wiring around to compensate for the difference in firing order. It will mess up the fuel
distribution and 4 cylinders will run lean and the other 4 will run rich. See http://fordfuelinjection.com/index.php?p=92 for more details.