The local O'Reilley Auto Parts store carries the standard kits.
Drilling won't be as difficult as tapping. Use some oil on the tap when tapping for the helicoil.
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
