1984 F-250 4x4 ext cab
460 performer motor
Edelbrock 700-750 cfm carb progressive 4 barrel all mechanical
Flat top pistons with valve reliefs
stroked to 514 cu. in
port polished heads
mild intake and exhaust porting on heads
stock distributer
Jacobs ingnition control and high voltage coil
RV Torquer cam about... 225/230 at.5 lift

I finally finished this motor on wednesday and fired it up on saturday.
set the timing and it runs fantastic at idle
Started driving it down the road and as soon as it hits 3000 RPMs the engine starts to cut out and lug. It simply will not rev above 3500 RPM. Unless you press the clutch in or are in 1st or 2nd gear. then it will run up to 5000 RPM but is somewhat sluggish. Way to sluggish for the amount of modification.

Is this a fuel problem?
Or ignition?

Or something im not thinking of?
The only other time that i ever had problems like this is when i had a bad alternator belt and the belt would slip and not make enough juice to run the spark. New belt fixed that and i didnt change anything in the spark system.

Any advice or similar problems or help or... anything really would be awesome. I just want it running. Been without it for almost three months now. Starting to get discouraged. Thanks!

 

I would lean towards a fuel problem. It sounds like the engine is using more then the fuel pump can keep up with. Do you have a mechanical or electric fuel pump? You my have to upgrade the size. Also check the fuel lines for a kink or sharp bend that closes the inner diameter of the line. From there make sure the pickup tube in the tank is clear of any junk. I normally blow, no more then 25psi, air back through the lines to the tank AFTER the gas cap is removed. I've had the pickup tube also corrode through inside the tank allowing air to be sucked in. That one took a little while to figure out. Last but not least, check your fuel filters or replace them if you can't remember when you last did.

 

Thanks harley. I have all elctric fuel pumps. And i found out that is indeed the problem. Today on my way to work it did the same thing but way way worse and i could tell by my guages its definantly not charging. So best guess is a bad alternator? It doesnt make enough juice to run the spark and all the electric fuel pumps. so im gonna slap an alternator on it tomorrow and see if that fixes it. Unless its something cheaper?

 

I would test the alt before spending any cash on it. It could be bad battery cables that are corroded inside, a bad VR, or any # of other things electrically.