350 Running Problems

Hello
Ok here is the deal,I have a 49 Ford Coupe with a 1972 350.Last year a mouse
had chewed threw the rubber fuel line so
the tank sat empty for about 6 mo.I put new fuel line on and it was fine for a while.Then it started running like crap,backfiring through the exaust,no power.I thought it was timing. I have replaced the Fuel pump,timing chain,put in HEI,all new plugs and wires,cleaned out the Elderbrock 600 cfm carb(new last year).It was fine for a while,now its doing it again.There seems to be good fuel pressure,compression test was also fine.
I also put 2 fuel filters,one befor the pump
and one after.At high rpms it seems fine but it hesitates when u punch it and it backfires out the exaust when you let off it
PLEASE ANY HELP!! I realy want to take it to GoodGuys this year.
Thanks

Ok I know this prob. sucks,but Please help me.
I have taken off the Elderbrock carb and put the original Quadrajet back on and now it runs great in the driveway but when I took it on a road test it crapped out agian,not backfiring so much but bogging out and sputtering(wants to die)
I had to baby it back home!!!!
PLEASE ANY HELP!!!

Check the sintered bronze filter where the fuel line goes into the quadrajet.

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