Woj;
I'm kind of halfway between Jerry and everyone else on this issue. I tend to be more of a nostalgic purist but I understand everyone's desire to have a cool/unique truck.
First thing I would do is get the existing 235 running right. It is a great engine and provides all the performance you really need. This is a classic case of having to balance what you want with what you need. Having a good running motor in your truck will give you time to scheme/dream about other alternatives.
After that, based on what I've heard about the challenges of multiple carbs (poor performance due to over-carbing and hassle to get synched correctly) if your only choices are multiple carbs or running a 409, I'd go with the 409. Like Jerry says, you may have some size and weight issues to deal with but they can be handled. The other option is to run the two dummy carbs and one real one on the three pack intake. To me that seems a bit like cheating. All the cool points go out the window when you have to hang your head when someone asks you a pointed question and admit that only one of the carbs is plumbed for fuel .
Having a cool truck is only cool as long as it is still easy to maintain and fun to drive. When the bling factor starts to affect your enjoyment and the usability of the truck it starts not to be cool anymore.
Anyway, that is a long way of saying it's up to you. It depends on how much work you want to put into the installation and maintenance of your truck. Hard to compare/contrast the workload involved in installing a big V-8 vs. making three carbs work on a straight six. Compare the "cost" of all those cool points with the ease and reliability of leaving a good running original 235 in it. Make sure you go into this with your eyes wide open and keep us posted on what you decide to do.
