[llyr]

i have a 1971 mustang with a 351 cleavlend and it runs good but when accelerating it has little miss fires and when i get going above 20 and give it a bit of gas it seemes slugest. it makes noice but doesnt really throw you back in the seat like it use to. i put a new timing chain and cleaned the carb . it does have what lookes like the stock coil though. so can you help me out ?

 

[bayerd]

Complete tune-up would be in order; i.e., spark plugs, points, condensor, Make sure you set the correct gap in the points and the plugs. Also might as well throw in some spark plug wires. I wouldn't suspect the coil but what the hey..change that too!

 

[camden]

problem fixed it was the timing it was a bit retarded, its a rocket now holy pie!!! 25 mph and able to brake loose and burn rubber

 

[Wren]

Sounds like it needs a full tune up.
Being '71 it's still got a points ign. system. Points wear, burn and crack alot. If you can, swap it to an elec. dizzy.

New plugs, cap, rotor, plug wires, points if staying with them, check and set timing, adjust carb for highest vac readings on a vac gauge., new fuel filter

The carb may be in need of a rebuild as well

 

[imported_Corey]

I would advanced your timing a little bit, and if that don't help, I would go for a tune up. If it's been awhile since you tuned it up, I would go ahead and put new plugs and plug wires in it.

 

[Gyles]

my charger was doing sort of the same thing. i cleaned my plugs replaced and upgraded my ignition to an MSD unit. i also replaced my wires and my distributer. then i tuned it timed it and it ran great.

 

[stanley]

I agree with the timing comment. Could also be a problem with the carb depending on the last time you replaced it.

 

[berdy]

sounds like you need to advance your cam timming just a hair