Exhaust manifolds

[RodnRudy]

Picked up these manifolds at a swap meet last weekend. I'm curious as to what year truck the would have come on. My 77 manifolds don't have the cast ribs between the ports and I've not seen any others like that. Every thing else on them are the same as my old rusted ones. I'm thinking I can eliminate the casting ribs without hurting the integrity of the castings? The casting date one the one that is legible is D 21 8 or 6. Help in identifying these please?

[Katrina/10]

Those are passenger car manifolds. For some reason, they had the bars between ports and trucks did not. The bars are not attractive, but are very effective at keeping the manifold straight. The manifolds without the bars always curl up and are difficult to fit.

[MJN]

346248 Right hand, 350, 75-77 Passenger car, Chevelle, Camaro, Monte Carlo

364747 is not listed in my books but a quick google search indicates it is also from a car application, most likely Camaro.

The reinforcing bars were added to the 'log style' manifolds to help prevent cracks that are common in this style manifold. You can probably remove them but will risk having them crack or warp.

[RodnRudy]

Thanks for the quick response fellas. I'll go ahead and use them as they came. This is a driver not a show piece. The left manifold does have a section cut out, I suspect for dip stick tube clearance. We'll find out when I finish installing the engine back in .

[THI]

I had a 1977 Monte Carlo (bought new) with those manifolds, I currently have a 1975 LagunaS3 still all original that also has those manifolds. I liked using that type when I used manifolds because they did not warp!

[Ironhorse]

I have those same manifolds on my 71 Chevelle with a 350 V8. The engine is not original to the Chevelle but do like the manifolds in question for the reasons given preventing any warping. Just a suggestion but I'd leave them as they are.