Can't wait for the summer to start with such a shirt!

Indeed, the car now runs on LPG & gasoline. Nothing has been adjusted, everything else is still stock, including the points ignition.

I would like to make some efficient modifications to the engine and other components. The HEI conversion is a no-brainer and I will start doing that soon. The cylinder head is the second thing on my list. I would like to explore with you guys what to do, how to do it, what components to use & what are the do's and dont's. I will use all info to create a solid plan for the local machineshop here in the Netherlands. It's my feeling they need such a plan, because it's not their daily business doing slant six'es.

If the cylinder head is finished, I would like to upgrade the intake/header/exhaust/mixer. No problem to make the car single fuel, LPG in this case.

Would any of you guys know a machine shop (you would recommend) who could do the job?

That is, delivering a "performance" 225 slant six cylinder head? I could buy a cylinder head in the USA, have it delivered to such a machine shop, have it modified, and send it to Europe. It would be not so much fun, but could save me a lot of worries whether a local machine shop here can do it.

I don't have any advice about getting a performance cylinder head. Dr Dodge might be able to fix you up with one.

As for your LPG system, it is a lot easier to optimize your ignition timing for LPG-only but, since your car is already dual fuel, you might want to consider leaving the fuel system alone.
See Dual Fuel Advance Curve

One the members here used a MegaJolt ignition system for his LPG truck. Search for 65CrewCabPW's posts.

_________________
1965 Plymouth Barracuda,
225 engine, Quadrajet, HEI, Dutra Duals, 904 Torqueflite, 2.76:1 axle, Addco front bar
Rods & Relics - Fort Erie, ON / Collector Car Tech

I like the '65 to '68 Fury wagons. They look great.