Exhaust manifold casting numbers

[Larry Langley]

Hi folks -

I discovered a split along the bottom of my passenger side exhaust manifold and noticed that its casting number was different than the one on the drivers side. It also had A.I.R. holes (plugged) but was not an A.I.R. car.

Before I replace the busted manifold, I would like to respectfully request a favor from anyone who knows.
Can someone assist me in determining the correct casting numbers for the left and right exhaust manifolds, please. I haven't found them in my AIM.

It is a '72, 200 HP, 350 ci, base engine w/ A/C and A/T, non California car.
I shall be indebted. Thanks!

 

[JohnZ]

The LH was casting #3932461 all year long; the RH was 3989036 for the first part of the year, and 3932461 (same as the LH side) for the later part of the year. None were drilled and tapped for A.I.R. except those with NB2 California Emissions.

 

[George Black]

JohnZ is correct. Also note that some 1972 LT1's had casting #386711 for both left and right side and some LT1's had the same #3932461 castings as the late 1972 350/200 hp that JohnZ mentions above.

 

[Larry Langley]

Thank You!!!

Gentlemen - thanks for your kind reply and information. What a great forum this is!!