raneman

Hi, Can anyone help please? Rebuilt a 351C with a 268H Comp Cam Edelbrock 2750 inlet manifold and a 1406 Edelbrock carb and Hedman headers, all new, heads were ported. Got it running but cannot increase revs above idle. will not pick up, electric choke is working. Ignition timing was set around 6 degrees and have tried advancing it but it runs not much better, still wont accelerate. Have blanked all open vacuum ports on carb and head. Distributor vacuum system is as stock. Any ideas please.

THUMPIN455

more advance... Try 8, then 10, then 12 initial.. Or shoot for a total of 32-38 max.. Do you have a dial back timing light? They are helpfull for doing the max timing adjustments.

The stock setting is for easy starting, and compatibility with the worst possible gasoline. Often you need more advance to wake them up. Change the cam, headers and intake, and you have an engine that needs a completely different timing curve. You can also get a kit that has different springs and weights in it so you can have the timing come in sooner and faster with RPM.

The thing you dont want is surging at idle and part throttle, or pinging anywhere in the RPM range. Pinging sounds like there is a coffee can under the hood filled with gravel and someone is shaking it vigorously...

valley firearms

If the timing adjustment don't work try looking into the primary ventures and throttle the gas with your hand. Make sure you are getting fuel. If you are getting a backfire out the carb don't try this[8D]. It could be your idle ports are giving it enough gas to run but starves when you gas it.

THUMPIN455

Oh duh. I just realized he said it isnt running. I had a brain fart... once you get it running refer to above post of mine.

make sure its firing when #1 is at TDC. Make sure it has fuel. Both of those and you are in. There are a bunch of threads in here about distributors and putting them in, finding TDC etc. Start there. If spark is right on, you have fuel, then your cam isnt timed properly. If you have it just one tooth off, you will bend some pushrods. You might want to check that. how do I know that? Well 8 degrees is too much advance on the cam, and a tooth is way more than 8 degrees.

Pull a valve cover and see if any pushrods are shaped like an S... or if they dont lay flat on a piece of glass

Colorado_Mustang

Did you degree the cam? Is it straight up? Off a tooth? Are the plug wires in the right order and not swapped?

dodgestang

I don't think I am clear on what your problem is.

You start car and it idles? Your post indicates yes.
You apply gas and what happens? Car stalls?

raneman

Hi, In answer to your question. The engine does not stall when I apply the gas it just keeps idling, a fast idle that is too. The throttle is working and the acceletator pump in the carb is working too. You can obviously hear it trying to take in more air as the throttle is opened but the engine does not respond to throttle opening.
Thanks

THUMPIN455

something is corked up. What mufflers do you have on it? Also did you use stock rockers or aftermarket roller rockers? Could be your valvetrain geometry is off.

raneman

Hi, In answer to you thinking something must be corked up. I have fitted a new exhaust system from Mustangs Unlimited, a twin system with their TURBO mufflers. As for the rockers they are new/stock and I had the short block rebuilt by a local reputable engine shop who degreed the cam so I would hope and think they did it correct. Just a dumb question! If I had the ignition timing 180 degrees out would it run at all?
Thanks

Colorado_Mustang

I've seen a 390 run with the wires 180* out. Just check them and make sure. If they are fine, think about uncorking the exhaust temporarily to exonerate it.