i have a number from a piston and i dont know what the piston is. like is it 12:1 compression or bored .30 over...... heres a pic. can anyone tell me what this number means?


http://i225.photobucket.com/albums/d...-/IMGP1387.jpg

 

its most likely the serial/part number from the manufacturer

 

The number is like a speed pro .030 over but they look like the summit brand. http://store.summitracing.com/partde...0&autoview=sku

 

Those are TRW forged pistons, .030 over.

 

sweet thanks guys. and one more question. i found some pitting on the last piston but all the others look fine. is this still good to run like that? heres a pic


http://i225.photobucket.com/albums/d...-/IMGP1385.jpg

i know the rust is normal from it sitting so long but the pitting looks kinda bad. should the piston be replaced? if it does im just getting 8 new pistons with 11:1 compression cuz i was told these were dome top pistons with 12:1 compression, but im not sure.

 

Those spots aren't going to hurt anything. The rings come in contact with the cylinder wall, not the top of the piston.

 

those wont cause hot spots or anything? im just being real careful with this motor cuz theres a lot of money i put into it already. i just dont want it blowing up 10 miles down the road.

 

What power level are you going for are you spraying it? It is kind of hard to tell how deep the pitting is and if it is corrosion(ie rust and only one cylinder), preignition or lastly A detonation issue. As I get older if I see something that bothers me I take it to the machine shop or else it will always be the "what if" in my mind. What have you done to the engine already? Also the pistons are a typical flat top the head and the stroke will determine the compression ratio typically not a 12:1 piston though. As you will notice when you pull up the summit link for the speed pro piston it has a TRW part number its the same company ...federal mogul. http://www.campbellenterprises.com/t...ro_pistons.htm
Obviously they are not exactly the same piston, Personally if I was to change one I would chage them all check the bore tolerences with the new piston specs and either bore/hone or hone to spec.

 

if the piston wont work ill definitly get new ones. and i want the total seal gapless ring set for it.

the motor has 3500 miles on it and the guy ran a tunnel ram with 2 holley 500 4 bbl carbs on it. he said it would perdetonate cuz of the 12:1 pistons. but i know now that they arent 12:1's and it was obviously running really rich. the motor the way it sits suposedly makes 600 crank horse. later down the road i wanna throw in 8:1's and put a blower on it with a meth setup. im not sure about nos though.

the engine has a 400 crank and i believe it has a fully forged bottom end. i know it has a full roller valvetrain, mild cam, high flow oil pump, trickflow angle plug aluminum heads with 64cc chambers, and full msd ignition. ask me anything else about the motor if you wanna know.

 

With the pistons the 64 cc head and the 3.75 inch stroke I would guess 10.5:1. You are looking at some big numbers for a n/a 383 I would doubt 600 hp with a mild cam. Do you know what was the cause of the rust?