Home Porting the Holley Carb!?....

I have never ported any carb in my life but that's about to change!

OK this is why i'm going down this road. As most of you know my 340 has gone to rest and replace with a 408. My original carb being to small (600 Vac sec) had to go. had a 750 carb that i have been setting on for years. rebuild it and put it on. Works Good!

Then one day, on some ones other thread, there is a Holley carb sheet posted up with all the jets, PVs, squirters, cfm exc.
What i learn, real fast was that my 750 DP (Double Pumper) was in fact a 600 DP.

We all know that 600 cfm leave a lot on the table for a 408. even a some what mild cam.

already had to drill small holes in the primary side butterfly to get the idle mixture to come around.
I have the 600 DP Carb or a 850 Demon DP that has already had all 4 butterfly drill out for a 500+cube bottle motor.
So my choice becomes a rebuild kit, hand full of jet, two new 30 cc squirter kits and welding up the holes in the throttle plates........or try my hand at porting a carb.

I have had a book on this and have wanted to try this for years. I have all the burs, sand paper roles, flapper wheels, exc so it wont cost me any money to try!

SO HERE IS WERE YOU ALL COME INTO PLAY!

How many have done this, and what are the pit falls or problems to look out for?

Thanks in advance,
OH and the carb is a Holley 4776