so i acquired a 78 d150 with a 318 2bbl carter carb for 500 bucks. Runs ok but the carb is missing parts and i need to replace it. Well i got a hold of a edelbrock 1406 for $50.00 so now i want to change out the manifold. Well problem is this...i have heard a lot about some of the 318 la's have small ports on the heads. Would i happen to have that in a 78'? looking online at the manifolds for a 318 they say "for 318,340,360" so they must be thinking i have the large ports.

 

well the only large port 318 engines were the ones originally equipped with a 4bbl.
I would just get a eldebrock performer and port match the heads to the intake.
If you dont, the mismatch will cause some serious turbulence and effect running.
Most intakes that say they are good for a 318 assume that you have changed the heads to the larger port heads like the 360 heads. (which is another option).
I think the only factory intake that might work would be a 4bbl intake off of a 273 with a 4bbl. You might be better just putting some 360 heads on it too.

 

What parts are missing? You may want to just look around for a stock carb if you want to fix it easy.

 

for a daily driver that "turbulence" isn't as bad as "hyped"; 360 heads and the drop in compression ratio due to larger chambers would be a larger power decrease.

 

Will the turbulence affect its performance enough to where i would notice driving problems?

I noticed these 2bbl to 4bbl adaptors (attach a 4bbl to a 2 bbl intake)
I know these cant be the best choice but would they work good enough? pro's and cons?

 

DO NOT put an adaptor from a 4 BBL carb to a 2 BBL intake; that WILL cause a performance bottleneck; but the 4 bbl intake to a set of regular 318 heads, not near as bad. For your uses you won't notice an issue. Find an intake like an SP-2P (edelbrock) that is made for teh "318-sized" ports; I think Offy or Wieand made one similar; the "holy grail" is an Edelbrock LD-4B but even a standard "Performer" )basically equal to a stock OEM Mopar intake except in alum instead of cast) would do you just fine.

 

I had a 360 4bbl manifold on my stock 318 when i bought it. It ran horrible due to overcarburation and the ports not matching. You will end up dumping raw gas into the cylinders. I recomment keeping the 2bbl manifold and putting on a holley 350 or 500cfm 2bbl if you crave performance. This is much less work and cheaper.