[T2] Timing type 4 engine

[Richard Jack]

Question about the timing on my 1974 type 4 motor.  It has stock dual carbs, with a single vac. Advance distributor with points.   

My question stems from my road trip this weekend.  My bus ran great until my second stop for fuel.  It had trouble starting and staying running.  I threw a timing light on it and when it was running rough at idle it was jumping from 8 to 12 advanced.  If I revved it a few times I could get it run a little better at 4 to 6 advanced.  It jumps around some.   

So I emailed the guy and he said,  "Glad the bus treating you well. I rebuilt the motor while I was working at danny's volks stuff, the summer before you bought it. New pistons and cylinders, new cam and  SOLID lifters, all new bearings, ect. I used solid lifters because I hate the hydraulics. Set the valves like a beetle .006. I didn't do anything to the distributor, just installed the pertronix type points set up and made sure it maxed out at 38degrees total advance. The only way to set the timing is total advance, you don't really care what it's doing at an idle. You need an adjustable timing light and an accurate timing mark. Did you ever get a new timing tab? if not get one from bus boys." (I did get a timing tab)

So, I replaced the petronix with points cause it went out after the first month I had the bus.  Second I reset the valves at .006 intake and .008 exhaust.  Now, ever once in awhile I get a pop when I start the bus that blows the small boot below the right hand carb, off.  It'll start but runs rough.  Once I push it back on it runs fine.  

So, the kicker is I ran the bus home pretty hard(lots of head wind). It ran great after I got it started, with advanced timing I talked about earlier.  (I didn't think it ran too hot cause I could touch the dipstick and it was cool, and the distributor was cool enough I could hold my hand on it)
 After arriving home, I guess the exhaust or engine or combined melted the lower part if the plastic fan guard.  Then before I noticed I started the bus(which started fine while once cool), and sucked in the guard parts into the fan.

I can pull the motor and clean all those pieces out, but what about the timing? Valves?  Torque the heads?  
I need a little help, please!  

Thanks for any advice!

Richard Jack
1974 westy
Lubbock, TX