5 or 10 thousands?? lol , might want to know what your talking about before you post, 10 thousands is a hell of a difference from 5 thousands.... first do a deck height of the piston and cylinder then deck the head and find out what those measurements are, once that is done there is a formula to find out the cc of your dome, and from there you can take and clean up the head both efficently and for max power, 21cc is a great pump gas dome.
86 ATC 500R the duner..
85 ATC 500R...the not quite finished faster duner
1985 ATC 250R Bone stock!!
1985 ATC250R mx/duner
1986 TRX370R MX/Duner
94 Banshee 400PV Cheetah 105RWHP