Ok so i know there are two different types of rocker boxes with different sized sealing flanges, how do i tell which one i have so i can get a new gasket.

Carl

Put a photo up of your rocker

Just had a look at my spare gasket and its in a
PAYEN gasket packet the no is CH865 and it measures 5/8 in wide 1/8 thick this it for a wide rocker

Jacko

got that in metric mate?

get some calipers, take your rocker cover off and measure the edge of the head, if i remember correctly you need the thin gasket if it measures about 9mm and the fatter gasket if it measures about 11/12mm.

Carbs on manifold

Come on how old are you
15mm x3mm = 5/8 x1/8 approx

30 lol

what part are you measuring? 30 is far too big, it'll be no more than 12mm (its the bit on the head the gasket sits - not the bit where the screws go in)

30 is his age lol