If I floor it from a dead stop, there is about a second delay. And it really only pulls once the RPMS get higher. Does this sound like theres too much or too little gas going to the carb?

 

Too little.

Is it a double pumper?

 

Yeah, but read my other post. The carb caught fire.

 

Unrelated.

Sounds like you've got more carb than engine. There is a certain RPM that you have to be above for a given size of engine before you can go WOT with a DP carb. The chart is on the Holley website. I'd have to look, but I think for a 305 and 650, that is something like 2000 RPMs.

 

Well I think what might have happened was the fuel pump wire came loose and the car died. So I got the plugged back in, let the motor run little bit, gave it some gas. Then when I floored it from dead stop, not enough fuel.

 

http://www.holley.com/data/TechServi...Carburetor.pdf

Here's the deal: When you first open up the throttle (doesn't matter if we're talking primaries or secondaries, mechanical or demand-based secondaries), the main metering system hasn't had any fuel flowing through it. It is drawn into the air stream through the booster venturi by air flow. So, which comes first, the chicken or the egg? In this case, air flow. Air flow without fuel is called "lean". To supply some fuel while the main metering system catches up to the air flow, the accelerator pump squirts some fuel into the air stream while the fuel starts flowing through the main metering system. By the time the accelerator pump squirt is used up, the main metering system should be adding the fuel to the air stream.

When you put a "large" double pumper on a "small" engine, the flow area available through the carb means the speed of the air flowing through the carb will be reduced. The booster venturi work based on the air zipping through them - reduce that speed, the vacuum pulling the fuel into the venturi will be reduced. Reduced vacuum, increased time to pull the fuel into the air stream. Eventually the fuel catches up to the amount of air and you start getting some power.

I overstated it a little. 650 CFM on a 305 engine needs about 1400-1500 RPM to start working. Possible solutions are: Larger secondary pump volume (50cc vs. stock 30cc) to make the squirt last longer; smaller carb; higher stalling torque converter.

This is all assuming everything else is up to snuff - float levels, jetting, accelerator pumps, ignition, etc.

 

OK thanks, I installed all new MSD system at same time. Ignition, distributor, coil. I just remembered too, I haven't done the gap on my spark plugs

 

if you have msd ignition gap your plugs at 60 or so ( if you have a 6al and blaster or equiv.) and ROLL into your throttle as the rpm's come up.... not real slow, but slow enough to let your motor come on before the holley unleashes its fury ( had a 650 dp on a 5.0 302 with mild porting many years ago and remember this exact thing...,) also if your carb catches fire, i would check your timing...!!!
this car ran 12.7 with stock short block and stock ported heads, stock cam, 4.10's drag radials, etc...... lots of other mods, car was waiting for the motor in the garage, had everything else done

 

same problem with my fathers 74 camaro. has a 62impalla 300hp 327 block, 69 z28 fulley cam with 74 camaro 350 heads and a torker manifold with a 650holley DP. has a m-21 in it. if you try to get it out of the hole hard at all it bogges bad and jumps all around wants to die pop all that stuff u have to be easy with it out of the hole but once you get the rpms up a lil u can mash it and it will pull hard through all 4 gears. I have rebuilt the carb and the P have jet size 62 and the S have 84s do you think the S jets are to big? we want to drag race it soon but there is no way to launch and get it out of the hole fast.

 

secondary jets are typically 6-8 larger than primaries if the primary has a PV and the secondary does not. FYI 355tpipickup

 

PV? we also just bought another 650 dp holley off a member from this site and i took it aparts to check it out, and he had 60 and 62 on the P and 60 62 on the S side what gives with this setup?

 

PV = power valve

Obviously the one you bought just tossed in some extra jets laying around. you would want 60/66 for example and tune from there. I believe I'm running 74/82 right now in my car which is a 8 jet difference from front to back.

 

Yep, sounds like somebody just threw some jets in there. Unless they thought they were "balancing" a weak vs. strong bank or something.

Jetting is a matter of giving the engine what it wants. Right now in the 396 I'm running 74 primary and 90 secondary - I never would have thought I'd ever jet with that big of a spread, but that's what it seems to like. The "standard" Proform jetting is 72/84.