300wheel hp or simply 300crank hp? Quite a decent difference between the 2 though neither is hard to make it all takes money.
Food and math for thought:
300crank hp is how much wheel hp? Well, we can assume anywhere from 20-30% drivetrain loss through the trans and differentials. So:
300 x 0.8 = 240 so roughly 240 wheel hp.
I estimate mine sits around 250 (look through my signature) as it made 223whp with just the m1, superchips pretend tuning, cotton air filter and a muffler swap. That's before I added a larger throttle body (52mm), real tuning (FlyinRyan) and headers. I'll post some pics shortly of what kind of difference Ryan's tuning does. So, with those changes I'm fairly confident that I'm around 250whp. That comes out to 312.5 roughly. Quite a bit of fun, however, if you're happy with that kind of output there's a much easier cheaper route.
Port the kegger
52mm tb
Shorties
SCT canned tune by Ryan
1.7s
and you'll probably make more than that and using the factory kegger will give you better drivability than I have now and it'll be much quicker until about 70mph.
Now if you wanna make 300 wheel hp, you'll want the M1 or airgap and definitely heads. I would do heads before cam simply because you'll get better drivability matching the cam to the head/intake combo than you would heads to intake/cam combo unless you know what you're doing with cam specs. EQs are a cheap aftermarket head that is basically a stock casting that flows about 40cfm more and is thicker so it won't crack along the valve seats. Jegs sells em bare (if you want port work done) or assembled. Airgap will be easier to acquire than an m1 simply because it's actually still produced and can be ordered like most any normal aftermarket part and they perform so similarly until things get crazy that it's simply preference until then.
m1/airgap with EQs, 1.7s, shorty headers, sct tuning, 52mm tb will put you in that range, even with factory cam but will cost more for obvious reasons.