Mopar purple .528 for a 383?

Nice what kind of aluminum heads? Regardless of brand/type they should have smaller closed chambers than the 906s which will give you a nice bump in compression and much better knock resistance. The Edelbrocks on my 360 are the "open" chamber (more like recessed closed chamber) versions intended for positive-deck 340 pistons but I'm running them on a 5.9L Magnum short block with stock pistons .050" below deck. I've accidentally had the initial+mechanical advance as high as 44 degrees BTDC (on 85-octane regular gas at 5000' elevation) and not once did I ever hear pinging. No shiny specks on the plugs either. I currently run 87-octane regular pump gas near sea level with 36 degrees and it screams with no signs of detonation.

On the other hand the 360 in my D200 pickup has stock open-chamber iron heads and stock cam with around 8.2:1 compression and that will ping when it's hot out with the total advance at 32 degrees, go figure. I'm about to put a colder (180-degree) thermostat in it to help with that.
Speedmaster victor copies, from a member on here, he did a bunch of work on the to make them “right” on the low deck. I’m getting the heads, offset roller rockers and pushrods. I needed rockers and pushrods for the solid cam anyway and this was a no brainer.

I just have to check everything very close. I have to look out for piston to valve, and valve/bore shrouding. Then I need to see how big of a compression bump I’m in for.