hi, i want to know if [link=http://www2.towerhobbies.com/cgi-bin/WTI0095P?FVSEARCH=THS1010R+&FVPROFIL=++&search3=Go]This[/link] fits on a o.s 18 cv-rx ?

Physiaclly it will fit. I actually ordered one from tower, but called them (to ask the same question that you are asking now) and thay told me that it is designed for a .18 engine (as the ad states). I don't know if there would be any performance issues or not, but I sent mine back anyway in favor of a Tsais pipe. I'm sure somebody else who knows more than I will chime in on this, but until then.... I hope this helps.

Yeah says its for a .15 so it should be fine with an .8. The only issue if any would if the header fits the OS or not.

so does any one else knows for a fact if this would fit fine in a o.s 18 cv-rx because i want to buy it but make sure its fits fine thanks!

man id like the header

if you are really unsure then why not look for a pipe set that is actually the recommended pipe for that OS .18 CV-RX engine?