340 heat riser experts

[mapletonmopar]

Rebuilding a set of 340 exhaust manifold for my T/A. I have a NOS heat riser kit that came with a smooth machined looking counter weight. The original counterweight is cast and flatter. Does anyone know if the original cast one is what would have come on the manifolds originally? Or was it a replacement at some point too? Attached is a picture showing both. Thanks for any help!

 

[floyd]

I’ve seen several survivor Trans Am cars with the machined style counter weight. I’ve also seen other 70 340 motors with the flatter style.

I believe the flat style was correct for 1968 into 1970 and then superseded by the machined style. Maybe it was a mid-year thing?

 

[floyd]

A couple of original Trans Am engines. The Sublime car was from Tim Wellborn's low-mile AAR survivor.

 

[mapletonmopar]

A couple of original Trans Am engines. The Sublime car was from Tim Wellborn's low-mile AAR survivor.

View attachment 150469

View attachment 150470

Awesome pictures guys! Id have to say the transam engines appear to be the machined version...