One alternative would be to have the stock 6.0L pistons fly cut for the difference. This is actually a common machining practice to get exacting P/V tolerances on HIPO engines.
I have also heard that most of the piston makers ( JE, Ross, Wiseco, etc ) will custom make pistons for a "nominal" fee. Not sure what nominal is but may be worth checking into.

 

On paper, the 6.0 pistons wouldn't need fly cutting. The deck is nearly identical for both the 4.8 and 6.0. Added to that, the 6.0 pistons are dished (recess=.048" X 3.340"), and the 4.8 uses a flat top, so I see no issues with the cam.

I suppose you can check on pistons for other makes. For Gen I motors, the pin diameters are .927 vs .945 for the LSx motors. A quick check showed nothing of common SBC applications with the requisite compression height (pin height). Too bad; Gen I SBC performance stuff is plentiful and cheap.

The pistons tkmrider mentions, are all forged. If you want to go that route, then you can certainly get anything you want, but it will still cost you $500+ for a set. If you were to use OEM 6.0 pistons, they would certainly be no worse than a stock motor (and many on this forum are boosting, squirting, and revving with OEM's). At $26 each, OEM's are a very economical way to go (and available in + sizes).

One advantage I see in custom forged pistons, is that you could request a longer skirt, since the shorter stroke would allow for it. This would go a long way toward greatly reducing piston slap, especially when using forged pistons. Just some thoughts.

Andy

 

Good thoughts there. There is definitely a barrier to the hp that people are making on stock pistons. Cracked ringlands seem like a common thing when the engine is seeing very stressful conditions. Yet on the other hand parish went pretty darn far with his setup using the stock pistons. I don' know if it was the turbo, with the pistons having a pressure on them all of the time. (boost, exhaust backpressure) Or what, but they would last long enough for me to save some moolah for a stroker kit.

I wonder if the LSx rods could be bushed for a full floating design and then used with a SBC, SBF or a SBD piston. I think I'll look at some online sites and see what they have to offer.

 

I found this wiseco piston for a ford 402 that has a 1.300" compression height. That would only be .031" down the hole. No idea on pin diameter though.

http://www.wiseco.com/PDFcatalogs/PT04-ford.pdf

I just looked through the speed-pro catalog online:

http://www.21cgt.com/FMWebCatalog/default.htm

I was looking through all of the ford, chrysler, chevrolet, buick, oldsmobile, pontiac applications and found nothing close to a 1.331" compression height. Looks like a custom piston is the only way to go for a forged or hypereutectic pistons for this 328 combo.

 

so has anyone built one of these yet. and i was thinking of useing forged 5.7" rods that would give you a r/s ratio of 1.74:1 then some custom pistons.
and maybe getting the stoke crank shot peened

 

I am going to build one, I have a 6 liter block and I have the 4.8 donor motor bought, just hafta go pick it up. Will be a while before I can provide any useful info though, I don't even have a vehicle to put it in yet, but I'm thinking S-10.

 

cool keep me posted if you would i'm thinking about ti for my 04 silverado and my turbo.

 

Sounds like a fun ride.
I'm waiting for my warranty to run out.
It's either going to be this or a 395 stroker. The 4.8/6.0 hybrid would be much cheaper though.