Your main problem is in the carb. It may not have come off a 261 originally. First make shure the accelerator pump is working. Look down the throte & work the throttle. you should get a squirt of gas each time you move the throttle off the stop. I assume you have a roch. model B. Take the top off & check the float level. Make shure the power piston goes into the hole & kicks the ball off it,s seat. You may have to go to a larger main jet or if you have the right drill bits you can drill it out .oo2-.003 inch.The part throttle surge may be caused by to much timeing or vacuum advance.
