I've searched around, and havent been able to find any concrete info. I've found a couple scattered posts in threads here on the tech and on other forums too, but nothing real solid.

I'm wondering if anybody has measured the piston and pin weights for gen 3 4.8, 5.3 dish, and gen 4 5.3 flat.

I'm helping a buddy put together the ultimate junkyard build (not spending money anywhere it doesn't need to be) just to see if we can.

If anybody has personally weighed any of the aforementioned pistons, or if anybody has a link to a gm technical data sheet, please share!

 

If you are concerned about the balance, don't be. Plenty of people have mix matched stock rotating assemblies with good luck.

 

Balance was my main concern here. We are planning on spinning this thing to 7000-7250 so any differences in balance at that range would be more noticeable at that range than at say 5500.

Would you slap 4.8 pistons on gen 3 rods and spin it that high without double checking? If you have and it's worked, maybe I could get away with it too...but I have notoriously bad luck so I doubt I could get away with it.

 

Try searching for a member here "Agearhead4life" I think his name is. I know he has a couple vids swapping 4.8 flat tops for 5.3's. Cant remember if he weighed them in the video or not. I think his vids are on youtube under same name also.

 

I actually watched the videos a while back. Really good idea of what a backyard build can be!

I have a press, and an induction rod heater so i won't have to use the torch, but if it gets the job done, then who am I to judge.

I'll send him a pm and see if he ever weighed any of the pistons/pins. thanks!

 

Between "denmah and agearhead4life" a lot can be learned on what can actually be done with some simple tools and ingenuity. And put down some serious power without the price tag of some of these builds you see.

Ive built my last after market parts motor and will be taking denmah's approach from now on. It hurts a lot less when you blow apart a $5-700 craigslist motor than it does $5k plus build.

 

I can tell you a gen 3 5.3 piston and rod weigh 50 grams less than a gen 4 rod and flattops. Minimal weight difference in pistons but if ur changing rods to and want piece of mind get it balanced. $ 250 it cost me for balancing.

 

Any new information on this subject? I'm also curious about the weight of a 5.3 dished piston vs a flat top (L33 or 4.8 piston).

 

From further research and pj's to other members, what I can gather is the 4.8 and 5.3 piston are about 5 grams apart. Nowhere near enough to necessitate a balance.

The Gen 3 and gen 4 rod and piston setup however has a much much larger difference and would definitely need a balance

 

the gen 4 pistons and rods have the gram weight etched into them...not sure about gen 3

they are sorted into bins at the factory to end up with a matching bob weight....within a tolerance band (that I dont know)



that said, I have thrown some 4.8 flat tops on 5.3 rods (gen 4 stuff) and put 'em on a gen 3 24x crank and banged it off the rev limiter set 6800 with 15psi on 'em.

as long as your tune is good, they'll run.