PwrdbyLS1

iTrader: (5)

I find a deal on a 408 LQ9 TSP short block, it's build with a Callies crank, eagle rods and diamond pistons. The guy said this engine should put compression around 10.5:1 according to the specs sheet he received. But he say it has -3cc dish pistons..?? This should raise compression to around 11.5:1 with gm gasket and a 0 deck. I think a -10cc pistons is more the right volume. I've check on TSP website and -10cc are available but only with a short block assembly.. so that's sound right. I have a picture of the short block, the piston are dish and look like a "mickey mouse" shape. -3cc only have valve relief normaly.
Here's the picture


Tell me what you think. Thanks!

justinj

iTrader: (2)

I have a tsp short block with the -10s. Not a bad set up, but if the price is right for the -3..then do it.

sixt9er

iTrader: (2)

I'm no genius, but that looks like a set of dished pistons! I can say that a TRUE flat-top piston (with the appropriate valve reliefs) USUALLY are about -3cc to -4cc. Looks like you have a 408 for a low compression/forced induction build. Still a good set-up either way...enjoy it!

PwrdbyLS1

iTrader: (5)

The problem with 11.5 of compression is fuel octane. I live in Canada and premium fuel are only 91 octane so 11:1 is near the max I can go.. except if I put a bigger cam.

sixt9er

iTrader: (2)

I hear you...with a 64cc chamber head, you should have less than 11:1 compression ratio (static) with those dished pistons...

justinj

iTrader: (2)

not trying to jack but I have -10 pistons and milled to 61 with the .40 head gasket.. what would that put me around then? I was thinking I was around 11:1? I run pump gas and its my dd.

PwrdbyLS1

iTrader: (5)

I would say around 11.4:1, with a deck at 0.000" and 4.100" bore diameter gasket.

sixt9er

iTrader: (2)

I don't think that a -10 piston with a 61cc chamber will give 11:1, unless you had a huge bore...say 4.125" or something...i'm no expert though...

smok'nZ

iTrader: (160)

i had -10.5's in on of my 408 shorts i think it was gonna need 59cc to get to 11.3-11.8

PwrdbyLS1

iTrader: (5)

I simply use this website to calculate static compression ratio, you only need to know your specs.
http://www.csgnetwork.com/compcalc.html

justinj

iTrader: (2)

Ok, so is this a bad thang that I'm not at 11.1 or is this good. What's the ups and downs?

PwrdbyLS1

iTrader: (5)

You're around 11.4:1 of compression, more compression = more low end torque and HP. Its bad if your engine detonate, I supposed you run 93 octane gas so you're ok.

Mguncowboy

iTrader: (2)

If it's a TSP engine call them and discuss it with one of the guys there. They could prob give u a positive id of exactly what piston u have based on ur photo as well. They're great peeps with great service - they will help u as best as they can.

sscamaroburn02

iTrader: (14)

yep best bet is to call tsp they built it they should have an idea