I have started the process of building my engine and I need to order parts. I am going 383 with a 6 inch rod. I had originally planned on doing ai stock casting 200cc head. But now that I am going 383, I might want to do their trickflow set up. I need to puchase pistons for the builder. I was planning on running the mahle powerpak piston kit. I don’t know if I should go with the –5cc flat tops SBC125030F05, or the –16cc inverted domes sbc125030i16. The car will be n/a on premium 91. I don’t know which top end I am for going to get yet. I kind of depends on what the bottom end costs me when its done. Can you give me any thoughts on which pistons to buy? I don’t know if the –5cc ones would be too much compression for stock heads, and the –16cc ones might not be enough for the trickflows. I guess I don’t know what the best compression ratio would be for the lt1. I looks to me that the –5cc pistons would put the compression ratio over 12.xx to one. would that be too much?

 

You haven't put enough thought into this yet. Is this a DD, just for the track, weekends, street, what? The CR is the first thing you nail down.

Do NOT buy individual components from different sources and expect them to balance CHEAPLY or sometimes ever. Just a note here. All SBC with a 1 piece rear main seal were external balanced from the factory.

I recommend you buy a pre balanced assembly.

And BTW I already did the same mistake and used 6 in rods on a 3.75 stroke. Guess where the wrist pin is?

Go back to standard length rod. You will thank me in the end.

 

It's is basically a leisure vehicle that will be taken to the track 6-8 times a year. It wont be a daily driver, used more for enjoyment as opposed to necessity. I am looking for a fun street car than performs well at the track as well. At first it was going to be a 355 with ai's 200cc head naturally aspirated. I just bought a new callies compstar 3.75 stroke crank from a member on this board. I had originally planned for a 11.5 compression ratio. I honestly dont know what is a good target compression ratio for a naturally aspirated 383. Any recommendations? I was thinking if i could get to around 450ish rwhp, i would be happy for a while. I will take into consideration the rod length. I had read that there are no oil ring spacers on the mahle pistons. I will have to do some research to see if a 5.7 rod will clear the crank i bought. I just thought a 6.0 rod piston combo would be lighter overall, and therefore be easier to balance. Just like everyone else, this project started out small, and is growing by the minute.

 

Your cam profile will help dictate what static compression ratio you need because what really matters is dynamic compression. I don't see how you can figure out what static compression you should have with out considering how much is bled off while the intake valve is closing.

And, not saying this is the best route to take, especially for a blower motor, but I built my present 383 engine with 6" rods and Mahle -26cc 400 gm. pistons and run 15# of boost. I got a pretty good running, dependable engine, and while I could have chose a shorter rod and a heavier, tougher piston, it has hung together remarkably well.