650 or 750 holley

750 dp carb (mechanical secondary carb)
>> The 4 corner idle is only on the 750 and 850 dp carbs.(4 screws)

all other double pumpers have only primary idle screws(2 screws)
A 750 dp is one of the best carbs ever made and works on everything, so in the future if you build a new motor it will work on that to.

Mine is set up on my 318 like this >>>>>>>>>
69 front jets
78 rear jets
4.5 power valve
40 shot in front
35 shot in rear
1 inch four hole spacer
Front pump cam in hole 1 on carb and hole two on the cam it self.
Rear pump cam is in hole 1 on carb and hole one on cam.

I keep the accelerator arms a little looser then stock and it works good.
This is the set up i use on my 360 bracket car engine and the only difference is the jet's.
Buy a brand new one and don't look back.
I just sold my new 750 dp off my 360 to my friend because the cheaper 750 vacume carb he just bought new ,would not idle with his motor, because at idle it was way to lean.(metering plate)

I had the idle screws all the way out and it ran like ****.

I sold my 750 dp to him, and went over and set it up on the car and it ran perfect \\\ the idle screws were turned out only about 1 turn.

Holley puts a leaner metering plate in there cheaper carbs and they just don't work as good as there 750 and 850 double pumper carbs.
I ordered a 700 carb and sent it back because it was a total different carb then the 750 double pumper carb.
I bit the bullet and bought a 750 hp series instead.
In a hp series a 650 has a 4 corner idle and has a good flowing metering plate and would work great on a 318,but i don't think i could justify spending all that money on a street 318.

A regular 750 double pumper works so good on my 318 that if you were to take it for a cruise, you would see it has no dead spots, and is easy to drive slow or fast.
Oh buy the way i bought the 750 i run on my 318 in 1996 for my 360 bracket car ,and it still works perfect, so now it's on my 318.:cya: