Either work towards all motor / all motor + n2O
(cams, cam gears, pistons, IM, TB, P&P, etc)

Or look into a JRSC
which would mean swapping out your 4-1 for a 4-2-1 (shorter primaries = good for JRSC)
and get a 3" tapered shortram (like comptech, again tapered shortram is good for JRSC)

pullies are not worth the cost. The alternator and PS pullies do very little, and the underdrive crank pullies mess with the harmonic balance of the engine and can cause serious problems down the road.