Needing help finding new rods and pistons because I cannot find forged pistons anywhere and conflicting results on the rod size 5.7 or 6in I just need help it’s a 79 L-48

 

A 5.7" steel I-Beam connecting rod and hypereutectic pistons is all you really need for an L48 overhaul. If you want forged pistons Speed Pro would be a good choice, Summit Racing is showing stock on a 4.030 in. Bore.

 

You can run Hypers with a lot tighter clearance than a forged. Less piston rock, better ring seal and less piston noise.
But if extremely high RPM is what you are after, forged are a stronger piston. Much more care in warm up is necessary. But if you break pistons then forged is for you.
I'm thinking if your running a stock L48 crank those forged pistons would be much more hassle than there worth.
think hypereutectic.

 

Is the block salvageable? Usually when a motor throws a rod 90% of the time it windows the side wall or busts out the cylinder. If it is AOK then consider yourself lucky. I would take the block to a reputable machine shop and have them inspect it and see what work it needs. Summit has Eagle rotating kits (crank, rods, pistons, rings, bearings, wrist pins) starting around $1200 or so. While Eagle isn’t necessarily the best out there but their stuff is ok for street applications. You’ll want to have the machinist to double check everything though. Even the best manufactures have parts out of spec slip through their QA process. Always verify.

 

I wouldn't even dick with any of the stock rotating assembly and get an Eagle or Scat balanced rotating assembly......I used both during the Pandemic and both are just fine.......take a piston and block to the machine shop for a bore and hone......that's it, less time and money. Have the block deck square decked .015......this will get you .005 to .010 in the hole.....and several suppliers make .028 thick head gaskets.....Easy Button.
You go getting pistons and rods then the crank need to be balanced....why balance a BS cast GM crank? The Eagle cast steel crank is MUCH stronger......
You hear about keyboard warriors talking about how they would NEVER use a balanced assembly.......well, I have, many times....don't worry about it.....you are not spinning high RPM's.....
One thing you WILL have to address with Eagle is that half of the time I have to use One over "X" bearing on crank, rods, or both.......Eagle likes to machine their **** fat......
I recently built a 385ci small block with an Eagle assembly and Mahle forged pistons with the LS style ring pack.......1.0/1.0/3.0mm.....there was a HUGE difference in the amount of force that was required to rotate the assembly by hand after the short block was built......the customer is running it and has 1000 miles on it already with zero oil issues....BUT, his Eagle assembly required X bearings on the mains to get .003......make sure you measure this carefully.

Jebby

 

they have them for both 5.7 or 6.0 r
Chevrolet SB ProTru Street Piston & Ring Sets-Competition Products
Connecting Rods (competitionproducts.com)

 

As it was stated by others: Find a good machine shop, carry them any parts (engine specific) that you feel you might want or be possible to reuse, and listen to what they have to say.

And yes, do be careful of the "keyboard warriors" whom spout off numbers from afar having not actually inspected anything, and suggests which parts are 'good enough' and/or that one should just skip certain "proper" procedures dismissing them as something one doesn't need to worry about; at least not without further personal involvement in your project, at least that beyond your initial inquiry.

Scott.

 

I'm guessing you are a bit inexperienced. Maybe a complete short block or even a crate motor is the better choice for you.

 

thank you all for the im not usually doing bottom engine work mostly top but thanks to my scenario I do luckily the rod shot through the oil pan so yay right? Lol anyways I’m wanting to go up wards of 300-350hp so would hypers be good enough for that?

 

5.7in is stock 350
6.0in is known as 355

L48 has dished pistons, don't look for those.
Look for L82 pistons. early or late up to 80.

this is IF block is ok

 

would a 6.0 be optimal or would o have to change the heads as well

 

pics of the carnage please

 

6.0 rods were never installed by the factory. If getting a whole 383" kit..then might as well get 6.0" rods and take advantage of the lighter piston. I'm not a hypereutectic fan....but if you only need 350 HP they are fine. But any mild 383 with decent heads is going to make 425+ with no drama.

I'd still look for forged 4032 material pistons. They can be fit pretty tight on clearance to reduce noise and oil use....and are tough as heck for most stuff. I've run 9 sec 1/4 miles with them at 7500 RPM.

JIM

 

Whew, I'm no expert but it sounds like you'd save a lot of time, money and heartache by getting a decent FB engine, or even a remanned short block. You can always rebuild the trashed engine at a later date. There's a lot of stuff to consider when rebuilding an engine.

 

it is a quasi stroke and 355 owners say they like them.
like said, do a real stroke, 383.

 

not enough money my budgets round 700$😭

 

More likely than not quality machine work will cost that.

 

Rod length doesn't change the stroke or cubes. A 355 is typically a 350 bored .030". The rod just hooks the crank to the piston.

JIM

 

Then the best choice is to find another shortblock on Facebook Marketplace maybe? They are out there as people part stuff out or convert to LS. If you chunked a rod, good chance there's at least a couple of bent valves...so headwork is needed also.....and if somehow the block survived....you need a crank also most likely. An L-48 is just a basic 350...so nothing fancy in it.

You could buy a reman connecting rod and a crankshaft kit and a piston and throw it together with some rings and a quickie hone and get it running again. Just depends on how much damage is in there.

JIM

 

6.00" rods require pistons with shorter compression height ( distance between the top of the piston and the wrist pin) no mater what you're doing with the engine.
A 355 ci is a 350 bored .030 over (3.48" stroke and a 4.030 bore)