The innovative Thunder & Lightning bolt-on cast aluminum exhaust header boosts your engine's performance 35-100HP! This unique foundry-tough cast tube style header incorporates four individual water jacketed 32" long runners and easily bolts on to most big block Chevy marine engines, including Mercury Bravo, Speedmaster, and Volvo installations.

Did you guys ever get the drill jigs developed for the Merc 525, 600/700SCi heads yet?

New set of headers going on a Pantera!

They have it running already. 598cid

https://www.youtube.com/watch?v=u-5P0vw1UqQ

Any options for the 496?

There hasn't even been options for normal bbc for 3 years now since COVID ended foundry production of these fwiw.

Anyone by chance have "one" for sale? I can't remember which side but I smoked one of these and am looking for a spare for my other brand new header to make a set.

I emailed them a few weeks back to ask and they confirmed there will be another production run. I don't know how many they need to justify a production run, but I'd be up for a pair to keep as spares.

ditto

In conversation with "Kaama", he says Bill told him they were gonna have them in june or july but that might have been in passing conversation, not confirmed.