I predict you will be very disappointed with your build. With 76cc heads, your static compression ratio is somewhere around 8.3:1 and will not work well with more cam.

The cam you have chosen closes the intake valve later than a stock cam, which would be a better choice for 8.3 SCR. The longer duration cam will lower the dynamic compression ratio into the toilet, along with cylinder pressure.

I'm pretty sure your vehicle will be slower than it was with stock parts.

To answer the question of carburetion, the rule of thumb is to use a vacuum secondaries carb if you are using a torque converter that stalls at less than 3000 rpm's. Over 3000 rpm's, you can use a double pumper to advantage.