1974 360 exhaust manifolds No heat riser???

[QuickBpBp]

Can anyone tell me why there would be no heat riser on a factory exhaust manifold when all others I have seen have them? It's part number 3418623 and matched with 3614368 both dated '73. Thanks in advance.

 

[QuickBpBp]

A member on another thought maybe it was welded up real good but this appears to have never been drilled…

 

[Don Frelier]

Are those for a truck?

I think they had an outer heat shield with a flex hose that ran to a trap door in the air cleaner snout.

 

[QuickBpBp]

Not that I know casting numbers show they fit A B and E body 71-3 340/360 cars..They even can replace the 68-70 manifolds but don’t flow as good. Another guy thought that too but as far as the casting numbers they don’t come up as truck..

Are those for a truck?

I think they had an outer heat shield with a flex hose that ran to a trap door in the air cleaner snout.