If you go +1mm on the valves you need to have the seats changed out and a new valve job. Changing out the seats is pricey sometimes. Also if the bowls are not ported when you go up in valve size you will see no gains and maybe even lose a little due to the increased shrouding. +.5mm can be done on the stock seats but again it is only worth it if the bowls are ported.

 

oh ok, thanks for the info KJ, helps me out alot

so in order i would need to:
get a real good port and polish
then get the +1mm or +.05mm seats changed
then get the 5 degree valve job

is this right? and as far as the +1mm oversizing, will this weaken my head and cause it to crack? should i only go .05mm?

 

????

 

need some more info

 

Stick with the smaller valves (depending on app) Bigger is not always better
Port, dont polish(a little secret)
NEVER go 5 angles on the vavle job, useless. 3 is all you need. The trick is picking the angles based on the application. Call me and we can discuss further. Matt 941-626-4715

 

pm.d

 

I guess i will just go with the size in the middle... u cant go wrong...
i hope