What is the best head to purchase?

I'm looking at the next upgrade to my 66cc engine and I'm looking to see what the best head addition might be. I am running the old style straight plug head currently with a NGK BP5HS and NT Speed carb and banana pipe.

Pirate Cycles - http://www.piratecycles1.com/picyhicohe.html

Puch 50cc hi hi - https://www.treatland.tv/Puch-50cc-Hi-compression-head-p/puch-hi-hi-comp-head-50cc-maxi.htm

Puch 70cc hi hi - https://www.treatland.tv/puch-moped-70cc-hi-compression-head-p/puch-hi-comp-head-70cc-maxi.htm

CR Machine tools - Stage 1 - http://www.ebay.com/itm/Motorized-b...Parts_Accessories&hash=item1e6f5e313d&vxp=mtr Or the Stage 2 - http://www.ebay.com/itm/Motorized-b...Parts_Accessories&hash=item1e71f5ab9f&vxp=mtr

Thanks for the help!

Thanks for the info. guys. Looks wise I like the CR machines heads as they look like more like the older style engines.

I pulled the trigger on a head from CR machine. Mainly I like the look and the fact that the engine might run a bit cooler. I'll let you guys know how it goes.

Got my CR Machine head today! It's a really nice piece for sure. I used to source fabricators for the previous company that I worked for and this is some nice fabrication work. It's way more beefy than the stock head and gives it a nice old style engine look since it's round. I haven't had a chance to ride the bike yet but just in turning it over initially it seems to be pretty close in compression to my previous straight chain head. I'm running one gasket with copper coating. I'll let you know how it runs but I know for sure that this should keep things cooler. Also, it comes with some nice hardware to secure the head; however my threads are 8mm x 1 and the supplied hardware is 8mm x 1.25 so I'm using my stainless steel washers and lock washer combo with the original acorns all seems to be secure.