Under powered. Any ideas

[brumster]

On the power thing, let's be honest, it could be an utter plethora of things and an internet forum is just going to throw you all sorts of potential problems and things to investigate the devil will be in the detail, particularly how you describe the issue and whether you miss minor details (not intentionally) or include stuff that's unrelated. There's nothing quite like having the car in front of you; everyone will have different approaches.

Systematic investigation/diagnosis, step by step, rule stuff out rather than trying to hit the nail on the head first time... If it just flats off at 2500rpm under load with no pull, the carb thing does sound a good first bet (my knowledge on Pintos is minimal to be fair). Maybe start there, fair does, but it could be so many other things around ignition/cam timing, fueling, electrical breakdown in the ignition, yada yada

[cb750]

I had exactly the same thing when I bought my car.  Although it ran fine at low revs and gave no indication that there was a problem, it struggled to get passed 2500 rpm.  Checked it over and found the following:

Valve clearances closed up with 2 cylinders having no clearance.

Spark plugs had never been changed, 1 had the tip missing and 2 had a ball of carbon on the end

Timing out of spec

ignition leads breaking down

I was amazed it ran at all!  SO before you start pulling things apart I would recommend carrying out a full service and then go from there

[Snapperpaul]

On 5/19/2019 at 1:36 PM, dandan62 said:

Ps.. forgot to say mine is a stainless monocoque. I think heavier than a 2b??

Lighter

[Snapperpaul]

First thing to check is if the throttle butterfly on the first choke opens fully when you put the accelerator pedal to the floor. The second choke won’t open unless there is enough vacuum.

[Guest David mcmaster]

I have now had the carb off. Fully cleaned and rebuilt. Timing set up with a strobe. Goes Great now. Lots of muck in the carbs new filters and what a difference. The engine note from 4000rpm now sings sweetly