Cruise friendly low 12's with a 340 Dart

Could you explain a "basic 4" kit". I assume you mean stroker kit but details would help.

Also, my current Weind Action Plus 8007 dual plane intake is a spread bore design. I'm using an adapter plate with a holley 3310VS. I've been told the adapter plate is robbing power and just switching to a spreadbore Edelbrock could make a big difference in power and economy. Ideas or suggestions???

Also, I'm not sure what the compression is on the current setup but it idles fine at 750rpm and pulls 10" of vacuum. I'm gonna put the compression guage on it and get some cranking pressure reading and report back.

I would stay away from spread bore carbs no matter what brand.
I don't think your loosing any power with that adapter unless it has smaller bores than the carb. That manifold should go on a stock motor and an rpm,ld340, air gap, should go on your 340. Go single plane if you have the cam and gears.