318 poly intake manifold/carb questions

crewcabdon · Post by **crewcabdon** » Mon Mar 06, 2006 12:43 pm

Mine currently has an oilbath aircleaner and 2 barrel carb??

I am curious as to what is a good upgrade. I have seen the 2x4 set up on the cars (two fourbarrel carbs) and I have seen the O.E. single 4 set up. Just curious if I should stay with an O.E. setup or is there a better aftermarket setup. Not looking for a drag motor, just to upgrade a little and keep it stock appearing. The 2x4 is not stock appearing for the truck, but would be a cool looking setup if it works good.

thanks
Don

Jeffc · Post by **Jeffc** » Mon Mar 06, 2006 1:39 pm

Really can not recommend the 2x4 for the truck engine unless you want to do up grades to the engine.
It was set up for a 9.2 to 1 compression poly car engine with a hotter cam than other engines. Truck engines were 8 to 1 compression (plus to get one will take $600 with unrebuilt carbs to over $1k with rebuilt ones. They came with a matched set of WCFB carbs that have not been made in over 40 years. Holley carbs will not work on this intake and 2 500cfm carbs are just too big for a stock poly truck engine).

Best up grade to the stock truck engine is the 4v stock castiron intake with a with a 500cfm 4v carb, next best it the Weaind (Holley) 4v low highrise alum intake (still made) with same size carb.
Stay away from the 600cfm carbs, their too big for the truck engine and you will have tuneing problems for the carb to engine size. The 500 should plop right on, adjust the needles and away you go......