Based on your pictures in post #54, looks like the stock cast iron intake.
No carb on the motor in those pictures, but a ‘71would have come with an oddball one year only Thermoquad. I love Thermoquads, but if it were me I would look for a ‘72 TQ and leave the ‘71 on the shelf (if you have it). TQ’s are limited on tuning parts now days, but the ‘72+ stuff is legions ahead of the ‘71 parts. And externally it should look identical.
Did you talk about carbs with your engine builder?
