You can get non-EGR version of the Performer, not have to deal with shaker issues and matching to small-block heads etc. There are gains in the top end to be had, are they worth it on a 403 in a TA, I wouldn't say so.
Oh, you mentioned the non-EGR swap too. 2 inches is a lot (Hello Ladies) and it moves the power band into a high-winding screamer which a 403 isn't ideal for anyway, unless designed for the strip and you like the challenge of something different. An early 350 might be a different ballgame. The cam and carb would have to be swapped to suit taller intake to justify its use, or it's just a whole lot of extra dramas and getting nothing from it.
I know nothing of the Sniper kit, is it currently stock height of the carburetor? Does the factory aircleaner fit without mods? How much spacer would you need to clear, or just completely in the way?
I had an old OL4B intake years ago off a 350, it had no EGR mounts and probably would clear. But they are now rare, and other than being alloy, probably didn't even flow better than stock. But it had an Edelbrock logo and that's what sold it. Think it had to be modified to even use HEI.
