I am new to this web stuff so bear with me.

Forget abot the four barrel on your six. It wont flow right and it will be a dog until you wind it up, unless you have a good, and i mean GOOD cam. If you want a REal Cam for your 235 get in touch with Howards Cams in Calif. For a custom Grind (like I did). The 235 is especially unique mostly because of the cylinder head ports. Yes, the 260's and292's have more C.i., But if you look in the intake and exhaust runners there are NO head bolt bosses cast into them. Why Chevrolet did this to a good flowing head I have no idea. The 235 head can outflow those larger cid's any day.
back to carburetion, you'll be much better off with two or three single barrels on that 235 than you will with a single four any way you try to tune it. Trust me. I know guys who have been running these things since the early fifties. I have built plenty of V-8 hot rod motors and when I bought this '60 Apache i thought I would give this little 235 a go. I couldn't be happier. My truck weighs 4120 lbs. and that little six i built has more torque pound for pound than those V-8's. My key was the cam, the WELL BALANCED THREE SINGLE ROCHESTERS (with .072 jets) and a GOOD BALANCING JOB! Someone told mw when I was building this motor ( Idid all the macining myself) that all straight sixes are inherently balanced and i didn't need to pay the extra (200 dollars) money to balace it. Let me tell you, When I'm going down the 101 highway here in SoCal at 100 mph in my huge straight six behemoth Ive got a bigger grin on my face than when I drove any of my hot rod v-8's.
Do yourself a favor, find a good shop, make sure that crank and rods are straight, port and polish the head get a good cam and tune it properly.
One more thing, these 235's have shims in the main caps and its hard to find a shop that will build it right, make SURE that crank spins free bfore assembly.