Are there any easy mods to get 300-500 rpm out of this moter, the prop is already labbed and I want to avoid changing because it's new

you need to drop down 2 pitch sizes. your prop is to big if you need that many rpm's. your killing your outdrive when you plane off.

Treadwell

Aftermarket exhaust manifolds and MSD ignition will get you close.

Like Treadwell said drop the pitch a couple of sizes. I have had my prop tweaked 3-4 x's trying to get the extra RPM......it is working! I'm installing a set of 1.7 ratio Crane Gold Rocker Arms , (hidden under a set of trick 2 piece Eickert Valve covers), to see if I can get a little more! Tinker, Tinker , Tinker.....

What about cmi headers, msd ignition and flame arrestor, what gains do yall think I would get

I am going to have to start charging you guys for the use of my name.

Good start. You may not get what you would want out of these upgrades, but it is a good starting point for bigger and better modifications. Good Luck!

I was thinking more on the lines of "Mr. Tinker Train " by the infamous OZZY. No offense! Good name! Great hobby, keeps you off the streets and in the drink!

youll get rom 100 to 200 rpm. but your gonna spend 5 grand vs buying one prop.

Treadwell

you would be better off selling your motor, and buying a hp 500. then you would be good to go.
Treadwell