4.0L build advice

[brimstone]

I've looked around at the Chevy valve swap. I don't like the idea for two reasons:

1. It looks like it will be a lot more machining than I wanted to have done. Not only will the valve seats need to be ground to a larger diameter, the guides need to be honed larger, and spring seats need to be cut down. I haven't seen it discussed much, but the Chevy valve stems are also a different length, so this means different retainers/locks, possibly different rocker arm geometry/different pushrod length? Overall just a lot more complicated than I want to get into. This is my first time doing internal engine work, I'd like to keep as much to stock dimensions as possible. I understand that the Chevy valves/springs can be had much cheaper than the MP stuff; however, I'm willing to spend the money, and if it requires more machine work to install some of that cost will come out in the end anyway.

2. The Chevy valves are not the size I was looking for (2.00/1.55), for several reasons:
-I've seen lots of mentions that larger valves are not utilized anyway due to valve shrouding in the combustion chamber, or exceeding the flow of the runners. I am going to port the runners a little and polish the chamber and can unshroud the valves a little if necessary, but I think the 2.00" intake is a bit large.
-I'm not increasing overall displacement, so I am not trying to move a significant percentage more air, just make the inefficient 4.0L non-crossflow head breathe a little easier. This is part of an overall system (better flowing intake/larger throttle body/ported runners/bigger valves/aftermarket header).
-The 0331 head is a bit more restrictive on the exhaust side, so that is more what I was concerned about opening up. The Chevy valves offer a .09" increase on the intake but only a .05" increase on the exhaust
-From what I have read, once I install a supercharger the intake valve size won't matter as much because of the positive pressure on the intake. It will be more important to increase exhaust flow and reduce backpressure as much as possible.

With all these considerations, I was really only considering going with the MP 1.97/1.56 valves at most (.06" increase intake and exhaust). I was also considering a 1.92/1.56 if opening the exhaust more than the intake will be beneficial, and I can do it without losing torque.

I understand the Chevy valves work for a lot of people, however: I am not increasing displacement, I am not increasing compression ratio, the engine is fuel injected rather than carberated, and I am planning for what will make the most of a supercharger down the road. So my engine will be quite a bit different from most of the others around here.

[krom]

You should take the advice of a guy that builds these for a living.

IMHO you are starting to fall into a trap of overthinking the wrong things.

Other than dusting off the spring pockets, the machining for chevy valves isn't any more than a required for a quality valve job on an engine with such high mileage

BTW you are effectively increasing displacement, and compression by adding a supercharger.