You keep saying you will “only do the heads”. You do realize that bolting your stock NPI aluminum intake to a set of trick flow heads is going to seriously choke them off, and result in little if any power increase, right? Likewise with the cams, putting heads that flow a lot more on the top end, and leaving cams that run out of breath at 4800rpms is going to make for a lackluster engine. The heads, cams, and intake manifold all work together. Trick flow heads with NPI cams and intake is going to be a complete dog!
As for compression ratio, more compression will always make more power across the whole powerband, as long as you have the octane to keep the knock away. Cam timing also comes into play here, so a cam with a lot of overlap (like the comp 268s or even 274s) will let you run a higher compression ratio than one with a very small overlap (like the stock NPI or even PI cams), but the realistic limit for 91-93 octane pump gas in a naturally aspirated engine is around 11:1. Much more than that, and even with aggressive lopey cams, you wind up having to back off timing which costs power, or run race fuel, which costs money. Either way though, 11:1 compression will require the right cams, and a lot of time spent tuning to get it to start, idle, run, and drive like a normal car.
So I say again, PI heads, cams, and intake manifold. Or if you want to blow extra money, PI heads and intake manifold, and the Comp 268 cams.
Oh, and I would upgrade the fuel pump for any of these combinations. The stock pump is 110lph, or at least it was 25 years ago. That means it is theoretically can support about 270hp, but remember that is crank horsepower, not accounting for parasitic losses from the accessories, or exhaust restrictions, or anything like that, and if it is either a 25 year old pump, or a Chinese made generic aftermarket replacement, then who knows how much volume it is actually putting out. A Walbro 255lph pump is cheap insurance to make sure you don’t run lean and burn up a piston.
