So I bought a set of Wiseco pro tru +4cc 3.903 pistons to use in my engine rebuild. The intent was to use the new pistons with the oem rods since the pistons are advertised as being a direct replacement for stock ones. My block, and internals are 98 ls1.
From what I am reading the oem rod is a .945" diameter pin and the supplied pins with the pistons are .943". Why the difference? Will these still work? I was looking around last night but I couldn't get a solid answer. Thanks

 

Looks like just about the right clearance to make em into floaters.

 

Don't the floating pins have a brass bearing on the rod though? And the press fit dont?

 

Yes the rods are generally different.

We were talking about pins though.

 

They'll still work if you have your .945" pins. You would just need the piston pin bores honed to the proper clearance with the larger pin.

 

So I either get newer floating style rods for it, or aftermarket rods or hone the pistons? Those are my options?

KCS, if I have the pistons honed, would I still use the clips supplied with the pistons?

 

If you hone the pistons to press-fit size and use the press-fit pins, the press fit of the pin in the rod retains the pins. Just like the old SBC and many others. Clips are not needed.

 

Pretty much. Like mentioned though, you won't need to use the the clips with the press fit rods since the rod will secure the pin in the bore.

 

Ok thanks. I'll call the machine shop and ask them how much to hone the new pistons.
Cheapest aftermarket rods I found were Scat rods in a 6.100 length and a .944" pin bore. They are 299 from ws6store. If the honing comes close to that I'm better off just putting the scat rods in it.
What year engine can I use rods from if I had to?

 

Any of the NA 5.3L to 6.2L engines after 2005 should have the bushed floating pin rods. They usually go for $50-$100 used.

 

I better get to looking then. Just in case.

 

I forgot to update this. I don't have a final answer on sizes but I checked the spec sheet that came with the pistons and it says they are .945" not the advertised .943" on TSP website. In order to hopefully speed up the process when they start on my build at the machine shop, i picked up a set of floating style rods on the cheap for them to just use whichever ones fit. They look much stronger than my old rods and I'm told they are indeed better. Hopefully we get to use the better floating ones.

 

Hey buddy, any update to this.
we in San Antonio too.
wanna buid a iron 6.0 370 with these pistons

 

Machine shop ended up honing the pin bores on the pistons and using the pins for floating rods

 

Right on. What rods did you use 3 Or 4 gen.

we are trying to build a budget lol 370 block
want 11.7 compression with 60cc and .040 gasket.
buddy prob gonna order prc225 heads, fast intake and a ms4/btr4/polutter style cam. I came up with a 236 242 113+2 49* ivc 56* evo
this is going in a 03z06 toy car.
I would like to see around 515 rw I think it is do able with the 1 7/8 headers and ls3/7 maf and a big filter

Jason

 

I believe they are gen 4. With what you have listed that goal should be achievable... I was going to do a 370 also but decided against it because I couldnt afford good enough heads to make it worth it.