> Never weighed the NA exhaust manifold, but the turbo manifold weighs 10
lbs.

    Stock NA manifold is HEAVY! Probably over 50lbs. I will try to weigh one
tomorrow and report back..... if I still have it in the shop. Should not
even be considered for an aviation conversion.
    It's built to withstand the heat of the air injection reactor system.
Basically, they inject air into the manifold via the vane-type air pump. It
afterburns the exhaust gasses in the exhaust manifold to clean up emissions.
Mike C.