converting my 09 iron to a 1200 with stock heads.Can someone fill me in on the pros and cons of 10:1 or 9:1 compression ratios

 

10:1 requires higher octane fuel, among other things that are not worth writing about, but it will also put out more bhp and torque than 9:1.

 

if your planning on upgrading your cams later to access more jam i'd go 10:1 cuz you'll need a higher compression to run em properly. if all yer doing is the conversion the 9:1 is fine. you'll be pleased with either set up. hey if yer mechanical go to eastwoodco.com and order their head porting kit to do a DIY port job while yer heads are off. as long as you got the tools like a generic motorcycle valve spring compressor($40 EBAY),valve guide tool($20 EBAY) an read instructions OK, you can do it your first time out cuz its super easy. oh this is just a basic head port equal to a shops stage 1 port job but advanced folks could and do use it for heavy duty shiit. i used on my ol 1993 883-1200 motor and my buell 1203 cyclone motor thats currently in my rusty ol 93 883 frame. good luck you'll get tonnes o advice on this site