Is there any company that makes forged or hypereutectic pistons for the 200? I have my OZ head. It has 51cc chambers. I could have them opened up a little, but I don't want to raise the compression ration too high. I am trying to avoid octane boost and water injection.

Any ideas?
Maybe you could help explain this to me.. Why do you think the compression ration is going to be high? I just went to the falconperformance compression ration calculator and plugged in the 51cc combustion chamber and upped the headgasket to .045 (average for a new composite style gasket) and it says 8.9:1 CR. Which I thought was OK for street use.

Have you done something else to the motor to push the CR higher then that? Decked the block? Are you planning on a turbo or blower on it later?

51cc chambers, with a .045 gasket, 3.71 bore (.03 overbore), and flat top pistons gives me 10:1 compression.
I guess another question would be: with Duraspark II, MSD, 272 cam, full roller rockers, gear drive . . . could I do 10:1 on pump with maybe some H20 injection in summer?
TRW makes the pistons you are wanting. You can get them made however you desire.

ACL in Oz might be able to supply hyper slugs to suit. You don't want/need forgies in this application. (FTF can tell you why.)
TRW? Do you have a link?

Also, anyone have any ideas or comments about 10:1 with water injection?

Try the compression calculater in the FPH sitein my signature link.

Even with the additional .030, I still get in the high 8 to 1.
I have to agree with stang200, when I punch in the 3.71 and change the combustion chamber to 51cc, .045 for head gasket, and also change to flattop pistons with 0 valve relief, I also get 10:1 cr according to your calculator. Are we doing something wrong?
Howdy Stang66200 and All:

IIRC there is a SBC piston that is close in size that is Hyperutectic, that could be adapted. Ask Jack.

As for CR, IMHO, you'll be happier keeping your ratio closer to 9:1, given the elevation at your locale. Here's my thought. As long as you're redoing the short block, use stock type cast piston, with a small, 6.5 cc dish, but deck your block to zero. There are several advantages to this plan; It comes out to a 9.4:1 CR, uses cheaper, easy to get pistons, decking the block gets the quench back to a better dimension- improving turbulence and combustion efficiency. All other things being equal, in a wedge-shaped combustion chamber engine, a dished piston will make more power that a Flat-topped piston. The dished piston is more knock resistant too. Finally, take the time to smooth and radius all edges and polish all surfaces in the combustion chamber. Polished surfaces will reflect heat and minimize compression creep due to carbon deposit build up. Carbon and crud has a harder time clinging to a smooth surface.

A cast piston is easily up to this level of performance. I would add ARP rod bolts as an inexpensive precaution.

I have not had experience with H2O injection, and given a choice, I'd rather not have to. Check with Mustang Geezer on that one.

Isn't the compression ratio calculator fun? I'd change the deck height dimension on a stock 200 block to .025", as a more typical number. If your block is not stock, then I hope your measured it, and use that number. That's true with all dimensions. Measure twice, write it down and be sure.

Adios, David
acl australia make a piston 6mkry9411 which i am using in my 250.
here the specs..

high silicon a504 alloy (12.4%) gives wear & scuff resistance and low thermal expansion .this allows low clearances for optimum ring guidance
and minimum bore loading.these are aprox 30% stronger than original.
reduced friction due to diamond cam turned skirts & low friction rings.

reduced weight (bare 488 grams) tapered pin 115 grams
highly scuff resistant and ductile molybdenum sg top ring
pressure balance groove delays build up of interring pressure to reduce
ring flutter at high rpm
these have a 8cc bowl 38.86mm comp height crown thickness 8.36mm
1.8mm bowl depth .
ADDO .might be able to put you on to a supplier in auzzie

cheers dave67xr6
I have not had experience with H2O injection, and given a choice, I'd rather not have to. Check with Mustang Geezer on that one.

You have to check and fill it every 4 or 5 hundred miles....After a while, you get used to it ;) :LOL: :LOL: