Which valve set would be more appropriate to fit to a 1600 twin port head 40 x 35 or 47 x 37 (I think that is the correct ratio)? It is not a super performance but I have the option to do up the heads and would rather do it right first time.

Many thanks

What are you up to John... a bit of work on the red special, or is some other project about to hit the road ???

47x37 is $#@% huge.... so I'm guessing a typo.

From memory my 1916 has 42x37 - that's with 044's that have had only fairly mild porting.

40 x 35.5 is the normal 1st step, same as 043's, then with more head work and cam, can bring head stock castings up to 44 x 38. 42 x 37 is a common intermediate size also, but unless your going to be changing camshafts, carbs, exhaust etc, you'll find 40 x 35.5 to be the go.
Col's 1600 wasn't even this big, somewhere around 37 x 33, and it made real good hp, ran a 14.8 1/4 mile in an otherwise stock beetle.

Dave the special is getting a touch up tired of middle field motorkhanakhanacross got the small cam and seeing what could be a sensable headwork to do.

Ahh, OK - cool - so the red mist is decending again... good stuff.

Thought about throwing some ratio rockers on it ??? Can just see it now... bit of headwork, twin carbs, nice exhaust and next to zero weight.... it'd almost fly !!!

John to give you a bit of a comparison, my old 1776 which you ahve driven. Were std valve sizes, but with a medium port and polish, along with a 3 angle valve job and unshroud on the valves. other than that the heads were stock.

If you go big on the heads you will loose velocity and start having other issues.

Been having a look at you picks on face book..... seems like your getting a nice family of VW's down there!