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Looks like easy performance gains are made buy machining heads.
Before sending heads to machine shop how do you measure cc?
What cc is stock 1994 xri 200?
Who do you recommend?
Needs to run on pump gas (91oct)
Head gaskets recommended?
Does anyone use solder to check squish before removing heads?(i have at-least .050 of squish with snowmobile engines for stretch)
Thanks Scott

Back in the days of when I was building Hi'po Merc's. you would use a piece of clear lexan or plexyglass. cut it to size of the side's of the head and big enuff to cover the crush ring would be for the head gasket. drill a hole in the lexan or plexy. install a spark plug . suport the head where you are looking down at the chambers. Put small amount of Gell seal or grease where the crush ring is to seal chamber. get a sureng or somthing that measures in CC . Clamp down plexy or lexan . pour
water or very light oil in to the hole of the plexy or lexan. Keep track of how many CC whent in to the chamber as you fill JUST to the glass ,and not out of the hole. OR you can go get a set of 135 / 150 2.0 heads, they have smaller chambers in them. REMEBER The 2.5 and 2.0 Thermo blocks cannot be used with the early 2.4 and 2.0 heads. It might be cheaper to find heads than taking yours to a shop. If this is an EFI I don't know if its a good Idea to try this. Becouse it may have Knock sensor's ,and put the ECU into a tail spin. Your not going to get a Real notice in power ,not unless the block has been ported. If it was me if it works don't fix it. You would be better putting plastic reeds in it.
Hope this helps.
Stew

Thanks for the reply stew.Have a set reeds going to install after winter.Still on the fence if im going to port.Need to remove power head to install upper solid mounts and thinking just send engine to jay smith and call it a day!

Cutting heads is the best bang for your buck upgrade. It's not monster power but you will feel a difference, pull the exhaust can and air box as long as your at it. You will need to rejet after doing these modifications. I see you are doing reeds too. Jay Smith builds motors but he doesn't do the porting Jim Ruck out of Wisconsin is the man for porting. Jay or Jim can cut your heads to 35cc and you will be able to run premium pump gas, it should bump compression up to 145 psi.

Chet,it's efi.Re-jetting not an option.That's where i'm on the fence,what programmers do they offer for efi engines?

I think you will be safe then but I would do a couple plug readings. Here is the best solution to mercury EFI engines http://www.brucatosvs.com/acu.html