Need guidance, running out of throttle.

[kridgleyud]

Looking for guidance/help/thoughts.  1940 dodge sedan back on road after resto.  Dual carbs, vac advance working, langdons HEI, 12V, mechanical fuel pump, fresh rebuilt motor, 3 speed column shift and ford 3.55 rear. 

 

She accelerates through 1st, 2nd and into 3rd fine ... But I find there is not enough throttle left to push past 2,000 rpm in 3rd. Flat roads, tops out at 48-50 mph at 2k per cellphone gps.  I feel like she should have some more room left to go past that, but pedal is to the floor.  She'll cruise there for miles without issues. 

 

Where to look first, directions, tips?  I see folks here say they can cruise at least 60 without issues. 

 

Not trying to race her around town, but feels dogged. 

[maddmaxx1949]

Just spitballing here but maybe running too rich as you add gas to it? so by the time you are hitting full throttle your ratio is off?

 

(Edit) And have you checked the linkage for your accelerator pedal. i.e. Pushing the pedal all the way down equals wide open on the carb. Possibly not pushing your valve all the way open?

Edited April 14, 2021 by maddmaxx1949

[greg g]

Have you visually verified the throttle plates are fully opened when the gas pedal is floored?  May e your advance isn't going through its full travel.  What do your plugs look like? Any restrictions in the exhaust system?  What does the vacuum gauge tell you?

[maddmaxx1949]

3 minutes ago, greg g said:

Have you visually verified the throttle plates are fully opened when the gas pedal is floored?

Thank you greg, throttle plate is the word I was thinking of when I said valve. Was on the tip of my tongue

[greg g]

Also, check your point gap.  If they have closed up, that effects coil dwell time and makes for a weak and or late spark which would effect running at higher rpms.

Edited April 15, 2021 by greg g

[kridgleyud]

Thanks for the pointers.  Going to out to car this weekend to take a look at pedal range vs carb fully open and pull the plugs for any signs there.

exhaust is dual manifolds into a single 2.5, so larger than original.  I'm going to check the vac advance as well and rev in neutral if previous don't show cause.

[Andydodge]

I'd be disconnecting the accelerator linkage at the carby, move the carby lever/s to full throttle and see if the unattached linkage will reach to the same position........if not then thats the problem, after that then vaccum, leads, plugs, etc.......andyd     

[Booger]

my first thought gas and linkage. lots of variables

[Adam H P15 D30]

Check your rubber fuel lines and make sure they aren't collapsing. Fuel tank pick up partially plugged?

[MackTheFinger]

As noted, best first guess would be throttle linkage. Another possibility, dragging, smoking hot brakes.. Hey, it happens!!