Carburetor stumble

[52 Bone Speed]

68 HGTS, thanks for that chart!! Worth a thousand words. AG, are you mounting cams in position 1 or 2? If in 1, move it to 2 for more rapid shot. Also what pump nozzles size and are you on the 30 or 50cc shot bowl?

 

[68 HEMI GTS]

68 HGTS, thanks for that chart!! Worth a thousand words. AG, are you mounting cams in position 1 or 2? If in 1, move it to 2 for more rapid shot. Also what pump nozzles size and are you on the 30 or 50cc shot bowl?

I’ll be honest, there’s no golden rule. Usually takes some experimenting to see what the combo likes. There’s so many things that play into the combo other than the carburetor. I was building a lot of dominators for a little while. I would test them on my road runner. I can tell you that even though I was building all 1050 carbs they all wanted slightly different tune ups and pumps shots. Just variations in the castings and models affected the tune ups even on the same engine. And then the tune up would change slightly depending on what combo the carb ended up on.

 

[Aron Gleason]

68 HGTS, thanks for that chart!! Worth a thousand words. AG, are you mounting cams in position 1 or 2? If in 1, move it to 2 for more rapid shot. Also what pump nozzles size and are you on the 30 or 50cc shot bowl?

The cams are in #1 hole. Squirters are 42 in front put in by the dyno guy who couldn't get the stumble out. And 31 in rear. Both pumps are 30cc.

 

[68 HEMI GTS]

Usually dyno guys aren’t neasesarely carb tuners. I’d shrink the primary side down. Run the big squirter in the back. With most of my dominators and most everything else I get by with a 35 in the front or even less.

 

[Aron Gleason]

Usually dyno guys aren’t neasesarely carb tuners. I’d shrink the primary side down. Run the big squirter in the back. With most of my dominators and most everything else I get by with a 35 in the front or even less.

Usually dyno guys aren’t neasesarely carb tuners. I’d shrink the primary side down. Run the big squirter in the back. With most of my dominators and most everything else I get by with a 35 in the front or even less.

I thought it didn't make sense that the guy never checked the pump arm. And clearance after removing the float bowls, or checked float level which is good. To me, a good tuner would've checked everything and not overlook anything. And yes, the primary squirter is way too big.

 

[Old Sparky]

I recently had my car dyno tuned. It runs alot cleaner, but still has a bad stumble. When cruising down the road I can stab the throttle and it will fall on its face. The carburetor is a modified 950 quick fuel/thumper carburetor. I've had everything from a 750 vacuum secondary carb to the 950. About 5 different carburetors. And they all have had the same stumble. What am I overlooking? I was told by a local tuner to put a 10.5 power valve in it, and to lock the distributor.

My guess is you need more juice pump and or bigger pump jets

 

[Aron Gleason]

Update on my stumble. Took it out today, and with the carburetor back to where it was when I got it it runs alot better. The stumble is still there, but it only stumbles less than 2 seconds and it goes like a bat out of hell. Cruise afr's are low 11's so I need to drop the PVRCs a little. But overall it's alot better.