Classic/Antique Car Repair: 73 Mustang fuel issue, explosive ordnance disposal, stock motor


Question
QUESTION: I recently recovered my '73 Mustang after 10 years of storage while I was serving over seas.  I dropped the tank and flushed it and got it back on the road.  The drivetrain is strong and rebuilt (351C 2V, 375hp).  I have been driving it without issue but this morning going to work it started sputtering as if starving for fuel.  I checked the inline filter and it had quite a bit of residue.  It is running but it won't accept a prompt of the throttle.  When I get on it, it still sputters out.  Can bad fuel or residual crap in the lines cause spark plugs to foul out?  I just need to get the thing back on the road.  Any guidance will help.  
Thanks,
TODD M. KUIKKA, SSgt, USAF
Explosive Ordnance Disposal

ANSWER: In short, yes. Filters are not 100% and a lot gets passed.

If you actually did a good job on the tank, you may have a few filters to change to get clean. You may consider some hoses ran to a larger filter temporarily.

---------- FOLLOW-UP ----------

QUESTION: So far it is working out but I am replacing the carb for good measure.  I replaced the plugs and it cleared up until I drove it.  I think the carb may have some issues with the needles being clogged.  
The next question I have is particular to the 73 Mustang 351C 2V.  I bought headers for it and found that the stock motor mounts restict about 3/4" for mounting.  I need about 1/2" for clearance.  Ever hear of anything like this or should I look at other then Headman headers?  I may end up buying new motor mounts and modifying them to fit to gain the extra 15-20hp.  Any tips?

Todd Kuikka

Answer
Headers at best, unless you really drop some big bucks, always seem to need a little modifying. See if you can heat the pipes and get the clearance. Changing th motor mount is another option. I have had to put front motor pins on once raising it about 4".