Another exhaust question - 2.5" rams horn

[bhap]

I have a pair of 2.5" rams horn manifolds on an L31 in a 62 C10 with torsion bar suspension. I'd like to find a 2.5" Y pipe to connect a 3" single exhaust. All of the Y-pipes I've found are either 2" or angled - does anyone know of a Y pipe that will work for my setup - center dump 2.5" into a single 3" outlet? The alternative would be to run 2.5" front pipes back to a merge pipe behind the engine and go single from there. Has anyone used 2.5" front pipes from a 64-65 Corvette? They look like they would fit, but I'd hate to have to buy them just to try. Right now I have no exhaust so I'm trying to get something I can install myself without welding rather than trailering the truck to an exhaust shop. Any suggestions appreciated.