Mopar Muscle Association UK

If you have another carb for it, then stick that on, failing that, take the carb off, check the jets, pv are all out of the box sizes, dry set the floats, adjust the idle screw 1-1/2 turns out, give it a good clean with carb cleaner and a visual check over, or ideally get a carb rebuild kit and download a holley rebuild video through google. To optimise the carb, timing needs to be correct first, then stick a vac gauge on it and adjust to max vac.
Mick

If the carb has been sitting a long time too, it will defiantly need a rebuild the tips of the needle valves deteriorat as well as the other rubber components over time and can cause over fueling especially if the float levels arnt set correctly.

A backfire can damage the power valve in the carb, I would do a carb rebuild before going any further plus do a compression test.

Out of interest where are you based?

A bit of an update.
Thanks for all the replies so far.
I checked the timing again and took off the rocker cover and found tdc and then re-arranged the plugs to suit.
I fitted the new carb as it would be rude not too.
Plumbed all the lines in and it fired straight up.

It idles but if you give it throttle it back fires through the carb, no badly but on occasion. I've fitted new leads from a rover v8 as that's all I could get my hands on.
I'm gonna change the plugs too, any recommendations?

I'm in Hampshire. Near Portsmouth

Have you checked for any vacuum leaks? Check all the ports on the carb are being used or are blocked.
Have you tried advancing the timing via twisting the dizzy in case it is too far retarded? If it's a small block advance the carb anti clockwise and see how the motor responds.
Try that and see if it picks up at idle. These cars like lots of initial ignition.

Cool, I'll give that a go. I think i plugged any unused vacuum ports etc.
There is always time for one last check though.