Jerry, so  Billet Bowls are more for a Bling Factor than for use? Figured the petcock mod was enough.

I view the LARGE billet float bowls as a public admission of the designer/creator and the end user as their gross ignorance about how a basic carburetor functions. 

We see a lot of guys replace the float valve with the wrong size.  A gravity feed fuel system needs a 3.5 mm float valve to supply the high hp engines.  3.5 mm is the stock size on the TM 38 OEM carburetor. 

The petcock mod will allow more than enough fuel to get to the carburetor if the vent in the cap is working properly and the fuel filter has sufficient flow rate.  Some of the small clear bullet shaped fuel filters will not flow adequately if they have much time on them. 

We have replaced enough burned pistons to fill a 55 gallon drum from gas caps using the billet piston shaped fuel cap vent check valves.  The check valves fail closed and prevent the tank from venting and it leans the carbs and burns pistons.  Some of these little bling valves require to much vacuum to open the check valve with the same piston burning results.

If the billet float bowls are the same volume as the stock bowls I view those billet float bowls as bling