Anybody have a pair they want to part with? Time to block those crossover passages. I'll use a different year than '49 but...well, you know
It's gonna be year round use. I know it's going to run like crap until the engines fully warmed up. It was the same on my 235 that was in my '51 Belair. When I split the manifold put the second outlet on the radiator side of the original. I had to cut the counter weight in half for the heat riser. I ended up switching the bimetal spring back and forth to lock it either opened or closed depending on the season. That lasted for one year. The next 3 years I left it closed (or opened depending on who you ask) with no exhaust going to the intake manifold. Even in the dead of winter, I just had to let the motor almost fully warm up but then there was absolutely no difference in how it ran.
Common knowledge - we block the ports to make the pipes rap .... we don't care much about how it warms up as long as it sounds right.
What mint mark? I've even got a bunch of those up here in Canada - but I wouldn't sell them for less than four times face value, due to high copper prices.