I'm having some problems figuring out what's could be the problem with my engine running properly. When I'm driving down the road at about 30 or 40 MPH you can feel the car very slightly lunges forward and slows back down. Could it be a misfire, or is it carb problems like adjustment, metering jets I'm not sure. Any thoughts?

craig_o_connor88@hotmail.com

Yes. Yes to all.
Possibly too much spark advance. Check for total advance. Try disconnecting and plugging vac. advance hose. Check for wandering timing mark.
Possibly misfire: check spark plugs, and wires very closely. If you have spark plug tubes and spark plug wire caps(for the tubes) , pull the seal back and watch down the tubes for arcing. They can easily be spotted at night.
Could be low fuel flow: bad pump, plugged filter, low float level, vacuum leak, and maybe too small of jets.
Some specifics(like carb type, engine/head year, ignition type, recent history, etc) might help.

fglmopar@aol.com

My engine was just rebuilt and it has just under 500 miles on it. Its an 82 engine in a 72 duster converted to solid lifters. Block is blueprinted and 0.030". Milled head 0.050" and put oversized chevy exhaust valves in with comp valve grind and bowl work. MP cam with 0.460"lift and 268 dur with 340 springs. Super six stock 2bbl carb and MP 6 into 1 header. I already had to slightly enlarge the idle jets because at idle it ran way too lean. I was wondering if it might be the same with the metering jets? any suggestions would be really appreciated

craig_o_connor88@hotmail.com

The engine has points ignition from my 72 engine that was in it, but I do have electronic ignition from a volare that I haven't put in yet. The plugs seem fine and it has brand new wires. my timing is set at 16 deg adv (base) and I've checked out the dwell with a meter and its perfect. Should the timing be advanced more because of the cam, along with maybe bigger metering jets?

craig_o_connor88@hotmail.com

Sixteen degrees is quite a bit of initial lead. If you have a 'dial back' timing light, see what your total advance is at say 3000rpm or whatever rpm the advance is all in. Check the postings for max slant six advance. For V8's its in the 34-38 range. If you have too much total advance you can get that surging feeling at cruise.
What type of carb? The jets are precision reamed/broached, so they flow properly. Drilling them out is not a good idea if there is a better alternative. Too much total advance coupled with lean mixture can encourage that surging problem.
I don't think adding another unknown(MSD) to the equation is a good idea until you sort this problem out.
I've got to ask, because this happened to me once, is the rocker shaft installed correctly, with the oiling holes down? Are the rockers getting plenty of oil?

fglmopar@aol.com

the carb that's on my car is the carter 2bbl and when I first put the engine in I set the rockers a little loose just to fire it up and when I reset them there was plently oil getting on the rockers

craig_o_connor88@hotmail.com

Good. I haven't had a lot of experience with Carter 2bbl, just stock rebuilds. The metering rod(s) are really for fine tuning. Change jets to make drastic changes in fuel. I have some Carter books with specs on rods and jets, but basically the jet has a hole with a certain cross sectional area. The rod is basically a designed obstruction with a specific dia. and thus a cross sectional area, also. The actual flow area is the first minus the second. Different applications have different sized(numbered)rods and jets. Richer is larger jet and/or smaller rod. So, if you can tell me what numbers you have I can tell you what you have and point you in the direction to go.

fglmopar@aol.com