I recently purchased a dodge D 100 prospector 1/2 ton that i am going to restore,It has the stock 318 2bbl holley carb,I have recently found a 340 4 bbl intake and was just wondering if any body knew if it would work on my 318 block  and any advice on what 4 bbl carb to use on my truck as it will be my daily driver when completed any info would be appreciated as this will ge my first dodge resto  

i dont think just the intake will work!!

you'll have to take the heads off of the 340 and put them on the 318 block if you wanted to use that intake!

The 340 heads and Intake swap will fit on the 318, but the compression will be around 7.2:1, which is not very good for performance but it's is if you wanna use low grade gas!!

im not 100% sure on this though, if someone eles is please let me know, i'd hate to be wrong   !!  

The manifold will bolt on, but the larger 340-sized manifiold ports will have your air-fuel mixture running right into the 318 heads small port window occluding the opening. A performance improvement over the 2-bbl? Well sure, but certainly not ideal. If you wish to retain the 318 heads the Ed. Performer is a closer fit. If you wish to make everything right-bigger heads, proper compression-it would certainly be easier to drop in a 360.  

A mild cam coupled with a closer fitting edelbrock performer manifold and a 4bbl carb will make a difference you'd feel on a 318.

Just adding the 4bbl manifold & carb by itself won't do much except use more gas.  

The replys are all right, although I have actually seen this swap done with positive results without changing the heads. Certainly not ideal, but a friends 318 Duster picked up a 2-3 tenths with a 340 intake and a 600 holley carb with no other changes. A set of 1 5/8 headers also helped the car pickup another 2 tenths.
If your on a budget than these upgrades will net you close to a half a second or 40-50 horse power.
 A nice increase for a cheap set of headers, a factory intake and a rebuilt Holley.  

Hi Doc,
Yeah, I know-I've done the swap a couple of times myself. My '69 D200 has a 318 w/360 intake, AVS, el. ign., 1-5/8" hdrs, 2-1/2" exh. It runs well, and after getting the adv. curve and carb set up it spins it's 12.50x33s all the way through 1st gear w/4.10s. My friend and I swapped an entire 340 top end including the 340 exh. manifolds onto his '70 318 D200 also. It ran great! Both cases were a "parts on hand" kind of deal though. Given my druthers I'd rather sell the 360 iron to help defray the cost of a used Performer. But yeah, it does the trick 'till the big block.