Thornton Headers

[oldsmobile joe]

i have a set of their cast iron w/z manifolds on my bbo in my 79 calais. i love them and they fit well

 

[olds307 and 403]

There is varying opinions, I say they will, BBO especially assuming 1 3/4" primaries an actual collector into a 2.5" outlet.

 

[olds307 and 403]

Have them, not installed.

The ball seems to be a little big for the Pypes DOF10S downpipe sockets, which are 2.25", however I tried a 2.5" socket and that's too big. As long as they seal is all that counts.

Thanks for this, I was planning on trying 2.25" dual exhaust reproduction down pipes all the way back to the mufflers on my 70S. I guess a little big is better than trying to fill a space. How does the quality look first hand on their headers?

 

[81cutlass]

I have the thronton headers in my wish list for my turbo 425 crank DX block build. They should work with turbo exhaust piping great 🙂

 

[kustomkyle]

Thanks for this, I was planning on trying 2.25" dual exhaust reproduction down pipes all the way back to the mufflers on my 70S. I guess a little big is better than trying to fill a space. How does the quality look first hand on their headers?

Flanges are about four times thicker than the standard cheap header. Welds look like a robot TIG weld.

Mounting surface is flat, the primary tubes were welded inside the flange opening and ground smooth.

The only thing that might be a problem is that the exhaust flange bolt holes are threaded. I would prefer a nut on the backside, but that's part of replicating factory mounting. They seem to be the same thread as the to-head mounting bolts that are provided.

Plan on getting the ARP 480-1101 bolts, as noted by rogue_ryder, the heads of the bolts need to be as small as possible because the tubes make them hard to get to.

Will be a little while before they are actually installed.