440 crapping out

[4forty]

Last month I had car tuned up, plugs, points, the usual, been running great with no problems, stopped at a store, came out and started car ,it seem to start missing a slightly but not bad, then started to get worse,  started it today and I could barely get up the road. missing real badly, backfiring, and running real rough. any ideas, points still look good, everything seems in order under hood?       It's a '72 440, card, intake, headers w/auto

[jwc]

I would start looking for a vacum leak, a craked line or a line off.if you have power brakes and its not stopping it could be the booster.