Race block /engine and or parts wanted

Hi Guys
I am in need of a race block/engine or parts of
I curently run a R5 in the class im in but the powers to be are making me change it at the end of the year (not happy about it but ???)
so i will start looking now
Basicly it needs to be a 340 (R3 R2 R1 ect) must be no bigger than 340 +60 thou std stroke,heads well still a ?? but they must have std valve angle
As you can imagine we have a **** load of hp with the r5 so what ever we get will need to be all the best quality
Open to all options
Ie blocks only ,complete engines that will require changeing to suite any r3 parts as i guess we may end up building one
Let me know if you have anything

Thanks