The Ford Barn

coxswain98 · 05-15-2025, 11:41 PM

Setup: .030 over, 77-B cam, dual points crab distributor, dual Holley 94s, 3.5 power valves, 51 jets in front carb 49 jets in the rear, both carbs rebuilt with tested floats and new needles. Currently no air cleaners to tune the engine.

I need some help!

I recently replaced to power valves since I was silly and had dual 7.5s causing bogging on throttle. With the 7.5s, I was able to sync the carbs just fine, both carbs pulling equal vacuum. It just died if I gave it gas, since the PVs were opening or were already open, flooding it.

Changed to 3.5 and while I was in there, checked my float settings and needles. Set the floats for a tilting engine. On startup, it idled like crap! But throttle response was amazing!

Cleaned the spark plugs of their blackened state and that helped with the idle. Idled even better at temp. When I grabbed the Unisync to start balancing, the rear carb is pulling a ton more air than the front. Nothing blocking it that I can see, and this wasn’t the case before the PV change.

Has anyone had this experience?

Additionally, I can see that the venturis are dripping fuel. My fuel pressure gauge says approx 2.75 psi and I’ve been tapping the needle housing to see if it is a stuck needle.

Any help would be appreciated!

05-15-2025, 11:41 PM	#1
coxswain98 Member Join Date: Jul 2020 Posts: 85	Edelbrock Slingshot air flow imbalance Setup: .030 over, 77-B cam, dual points crab distributor, dual Holley 94s, 3.5 power valves, 51 jets in front carb 49 jets in the rear, both carbs rebuilt with tested floats and new needles. Currently no air cleaners to tune the engine. I need some help! I recently replaced to power valves since I was silly and had dual 7.5s causing bogging on throttle. With the 7.5s, I was able to sync the carbs just fine, both carbs pulling equal vacuum. It just died if I gave it gas, since the PVs were opening or were already open, flooding it. Changed to 3.5 and while I was in there, checked my float settings and needles. Set the floats for a tilting engine. On startup, it idled like crap! But throttle response was amazing! Cleaned the spark plugs of their blackened state and that helped with the idle. Idled even better at temp. When I grabbed the Unisync to start balancing, the rear carb is pulling a ton more air than the front. Nothing blocking it that I can see, and this wasn’t the case before the PV change. Has anyone had this experience? Additionally, I can see that the venturis are dripping fuel. My fuel pressure gauge says approx 2.75 psi and I’ve been tapping the needle housing to see if it is a stuck needle. Any help would be appreciated!