1985 1/2 ton Truck with TBI vortex engine

[DustermDuke]

I have a 85 Chevy Truck, i put a 305 vortex engine it has the 2 bbl TBI on it and I would like to put a 4bbl Cab on it, What way should I go?

[jveik]

all you gotta do is switch out the intake manifold for an edelbrock intake, they make ones that fit on vortec heads (vortecs have the 4 bolts running along the top, while most others have 4 around the side called perimeter pattern). then get a carb prolly 550cfm will be sufficient, and stick it on there. dont get a very big carb, cause the engine is only a stock 305 and will not need anywhere near that much fuel and air. if its slightly modified, like a lumpy cam or something like that, go with a 600cfm. since it is a truck, make sure you get one with vaccuum secondaries and NOT mechanical secondaries, if you want to know why, search the forums for it and there are many explanations for why this is so. basically, the mechanical secondary carbs are for lighter cars and vaccuum is for heavier cars, like your truck, although if tuned properly, there are always exceptions...