what is the performance diff if any? 6.125 rod and stock rods

 

Just the length of the rod. You have get pistons made for that length of rod. The wrist pin will be offset.

 

A longer rod would be better than a shorter one.

 

from what I have been told it keeps this piston up top longer allowing the combustion process to burn more efficiently actually completing more of the burn cycle.. kinda... i think I worded that right?

 

The other advantage of a longer rod is that it allows the piston to push more directly on the crank journal. In addition to the piston hanging around TDC longer. Keep in mind though, the LS1 stock is 6.100, so a 6.125 is not getting you much. Chevy already equipped the LS1 with a much longer rod than in the old 350 Chev (5.700") and much longer than the old Chev 400 (4.565").

 

they increase the dwell time at tdc and bdc, which if memory serves helps cylinder fill and exhaust effiencies. they are also easier on the pistons and cylinder walls.

 

the old 400 SBC had a 5.5 rod.

 

yeah I think he meant 5.565 not 4.565

 

I'm getting ready to order some new rods from TR. I'm not trying to steal the thread here, but what are 7.400 rods? I thought that was length.

 

7.4" are the pushrods. They are completely different from the connecting rods. Pushrods go betweend the lifters and rocker arms whereas the con rods go between the crank and pistons.

 

LOL Got it.... thanks.