tomme12

Not sure if this is the correct forum. We have a 289 shelby kit cobra. Holley 600 carb, hauls ****, etc.

She's great up to around 3k, then all of sudden just dies out after 3k. Almost like you turned the key off (but still running). Fuel pressure tests (while running) are ok, carb is clean. new fuel line from tank.... im beside myself on what it could be.

no vacuum leaks (check with gauge)

Points look good.... Im about ready to put it on a dyno and have someone figure it out. But figure I would ask you ford experts first.

Only thing I have not checked, not sure if the tank has an antisiphon valve, which maybe its clogged?

Any input would be great

Car collector

I wouldn't be sure without driving the car but some idea's I'll toss about

Vapor lock- (had this on an old jeep and again on a el camino) But this is where the gas line gets hot and the fuel separates before getting to the carb so your basibly pumping air in but this would usually occur after the car has been driven awhile and would stop once the line has cooled

Fuel pump can't keep up - you said you tested this one and the pressure was fine but thought i would include it just to be safe.

Too much carb not enough motor, granted i doubt this is the case but again something just to toss out there.

So what all have you tried to diagnose this? maybe we can take that information and come up with different ideas

tomme12

Thanks the reply.

New fuel pump
New fuel line from Gas tank to Fuel pump
New fuel filter between fuel pump and holley.

Can you describe vapor lock a little more? Im thinking it might be this or the line is bad between the fuel pump and holley

Bubba 95SN

Take gas cap off and try. Hook up dwell meter while driving make sure points are not bouncing.

nitrous_bob

i would gap the plugs way down to about .035"

if it fixes the problem it is spark related and you can rule out fuel issues.

tomme12

Thanks all for the replies! When I get a chance, I will give these suggestions a try. They all make sense for narrowing this down.

67mustang302

Do what Bob said. Also when was the last time points were adjusted?