http://www.venolia.com
I called Venolia earlier this year about custom pistons for my stage motor. You can get a custom order set of forged turbo pistons with heavy duty pins for around $500 and it takes about 4 weeks. An $80 or so set of speed pro rings and away you go. This would be a custom piston made to exactly how you want it for right at what the turbo buick venders want for off the shelf stuff. Ordering custom pistons is real easy also. I ordered a custom set for my self and a set for my good buddy. You need the machine shop to tell you what the finished bore would be, and you want to go with the smallest bore you can, your custom ordering them anyway so you dont have to eat up and weaken the block. The other thing you need is the deck height measured. The other things you need to tell them are:
1. desired compression ratio: which you probably want in the 8.0 to 9.0 to 1 range
2. stroke length : 3.400"
3. rod length : 5.960"
4. deck clearance: 0.025" that can very but this is good choice for a street motor
5. you would want a dished piston, a reversed dome would be a waiste of money
6. you would want a fully skurted piston, little more friction but alot stronger for turbo motor.
7. compressed volume of your head gaskets, unless you picked an off the wall gasket this should be right around 8 to 9 cc's
8. tell them you would want to go with a standard ring package, which refers to the width or thickness of the rings, I can't remember off hand but will look up if you want.
9. combustion chamber volume of the heads, you could have this measured at the machine shop or ask what the cc's of stock heads are.
Do not get all ate up about an exact compression ratio. Most people who know exactly what there compression ratio is are more than likely exactly wrong. People are just way to lazy to do the math with all the exact numbers, because almost no one takes exact measurements. The custom pistons will put you dead on in reguards to a few of those things, so if you off a cc or 2 on chamber volume and a cc on the head gasket it will be no big deal. A cc or two has very little effect on the compression ratio of a low compression motor. If you wanted 8.5 to 1 and:
you had 2cc to much you would be at 8.34 to 1
you had 2cc to small you would be at 8.66 to 1
You would be splitting hairs if you started arguing the difference in the motor between 8.34, 8.5, and 8.66 to 1. "off the shelf" pistons would very ALOT more than this.
Thats pretty much it. Remember that they are the experts and they do pistons for a living. They will step you right through every question and then they will do all the math and such. Its really a very easy process and you personally don't have to know a single thing about pistons. I went with Diamond Racing pistons due to a vendor oweing me money and he sells Diamonds. If I was sending off my own money I would have went with the Venolias because they have been around a LONG TIME and had the best price.
HTH: Jason
