hei type distributor 73 340 duster
first is this a smart move?
In my opinion. No.
There is no advantage inherent in HEI that will outweigh having the correct timing curve.
Good HEI has the potential advantage of being able to continue providing spark energy, which is really only helpful if the kernal of flame around the spark tip doesn't grow as it should.
can use the plug wires i have now? they do work fine
Depends on the cap that comes with the new distributor.
also would i need a spark box like MSD street fire unit?
?? No. The GM HEI distributors were designed to have that function built into the module which was included with the distributor. You answered that yourself here
eliminate..., and ecu box
i have heard the proform unit 67040 which is what i am looking at is larger then the stock unit i am using now.
If its larger than factory and going on a small block, you know that there is limited room to begin with. Maybe a little better with later firewalls but always tight.
There's even cheaper versions on the market. Not only do they provide the wrong timing curve, but they self destruct. ;)
racingfuelsystems-cheap HEI distributors
Seriously. Do yourself a favor and save your money. If something needs fixing, then fix it. If you want to do a little performance tuning, make one small change and test it out under every condition it needs to perform. Then do another, keeping notes.
'73 Came with the OSAC. If that's not been bypassed, then do yourself a favor and bypass it and there will be a lot better part throttle response.