Externally-polished 38mm flange-style manifold is 4-1/4" long When combined with 4000250 adapter, it will accept spigot-style carbs, or by drilling the flange holes out with an 11/32 bit, it will accept flange-style carbs with 2-3/4" center-to-center holes More spacing for flange-style carbs may be acquired by using a 4000095 insulated spacer