Joe,
I have done it both ways (with one or two carburetors)
Will you be using one or two carburetors?
Some people will tell you that two carburetors on a 216/235/261 stovebolt engine is just eye candy (so what, if they are a good match to your engine). What carburetor/carburetors are you using?
Manifold heat is easier/better with regards to messiness if/when you get leaks.
I either case, water or exhaust-gas, what intake and exhaust manifolds will you be using? Some/most dual carburetor intake manifolds (and adapter plates) do not move the "coolant" as follows:
into one side
and then side-to-side
and then out the other side
If you post a photo or link to the opening on the bottom of your intake manifold, I/we can post further comments.
With regards to mufflers. why glass pack?
Stock 235 mufflers are straight-through, with baffles.
Nice mellow sound (a little "rapping"), with little/no back pressure.
You might get replies that tell you that this is all "eye/noise" candy.
Even though they are mostly correct, ignore them.
