Stocker pin dia.
 

The rule states that the stock wrist pin diameter MUST be retained, yet in the case of the LS1 the OE pin diameter is .945", yet all the approved rods have .927 diameter small ends?

Re: Stocker pin dia.
 

And some Fords are allowed Chevrolet aftermarket rods. Just a concession to parts availability I'm sure. Once allowed, even if the correct part becomes available, they usually do not change the legality of already approved parts.

Re: Stocker pin dia.
 

There are plenty of .945" rods available, but none of them made the list. So the legal rod with it's .927" pin and pin bore supersedes the stock diameter pin requirement?

Re: Stocker pin dia.
 

The question is how many aftermarket rods with the correct pin diameter were available when the first aftermarket rods were accepted for the application. I do not know the answer.

I'd say you should probably call Wesley Roberson to make sure that you would not have to open the rod up 0.018" to accept a 0.945" pin.

Re: Stocker pin dia.
 

Look on the Rod list, it says this...(Must use OE size pin or larger) for stock, regardles of how it is produced you gotta keep the size on the piston sheet.or larger ...

Re: Stocker pin dia.
 

In know from experience, if NHRA provides an aftermarket rod and the pin size is different than OEM, you are allowed the aftermarket size that the rod is built around. This is due to most aftermarket rods being built around a .927" pin and 2.100" large end as most aftermarket rods are built off a SBC blank.

Re: Stocker pin dia.
 

Jeff,

In my experience a couple of years ago, we were advised that we had to keep the original pin size as per Bub's post. The motor in question was a 307 Oldsmobile that had an approved 6" Chevy rod but we were told that we had to use the stock pin size (.990 as I recall) in order to be legal. I haven't heard of that rule being rescinded.

c

Re: Stocker pin dia.
 

Been down that path w/ NHRA. FE Ford and AMC are two examples I know of. There's not enough material left in the approved rods (stress approved rods)if you run the OEM size pin. That was from Glendora.

Re: Stocker pin dia.
 

If you go to the complete piston and rod list, the LS1 piston has been approved with the .927 pin. Also the piston is approved with 1/16 1/16 3/16 rings, with optional 1.2 1.5 2.0 ? rings. I guess you can't believe anything NHRA tells you, even if its in writing!!

Bruce

Re: Stocker pin dia.
 

I think your correct Bruce... all you need to do is build it, look at (ALL) the sheets...copy and bring them with u to teardown. and hope they don't change their minds,,, again

Re: Stocker pin dia.
 

I got a response back from NHRA today, has to be the .945" pin in this case, looks like I'll be boring the new rods and buying new pins.

Re: Stocker pin dia.
 

Does the rod really have to be on the approved list in Stock?? as long it has the right pin bore and housing bore correct length(unsure about Ford FE ) made of steel and the total weight of the assembly is greater than published one should be fine..wouldn't you think??I would belive with the total assembly weights in stock the rod list is more for SS!

Re: Stocker pin dia.
 

RJ If you got a response from Pat Cvengros at NHRA in Ca, take it with a grain of salt. If you got it from Wesley than it will be as he says. I was told last year that all pistons must be the same as the example that was on there shelves in Ca. I wonder what the pin sizes are on the examples and why does the approved list show .927.


Bruce

Re: Stocker pin dia.
 

RJ, back in 1998-99, NHRA approved the 927 pin because the aftermarket pistons were being made with 927 pins and also Manley Rods. I think Pat is missing something there.