Inliners International Forums General Discussion Hi Performance Connecting rod lengths

In our pursuit of a replacement performance rod for the Hemi 6 engine we have found that Scat make a 6.0" rod for the Chev inline 6 which suits our needs.

It does have to be modified, but not to a difficult degree, but it opens the question about whether or not there are other rods out there for the Chevy 6 which might suit us.

In particular we could probably use a slightly shorter rod and a slightly longer rod. The 2.0" crank pin size is the key dimension shared with the Chev engine, while V8 rods are no good because the big end width has to be at least 0.970".

Are there other rods we can use?

Eagle is another company that has some budget H-beam rods for the Chevy 194-250 engines. Crower has a Sportsman rod available in an I-beam style. But a 5.700" or 6.00" length is all that is available right now. Of course many companies can make a custom length at a big price tag, but it likely wont appeal to many customers because of the price.

As Scat do make rods in 5.850" and 6.125" lengths for the 2.0" crankpin Chev V8s indicates it might be easy for them to make some up with the slight variation of an extra 0.030" width in the big end.

I'm hoping so.

Don't get your hopes up too high. I've asked them before and they said that the forgings are made with such tight dimensions that they are almost on the finish size when forged, and have very little material left to remove to reach the final dimension.

They've got to be kidding?

I can't believe that. There would be latitude in their forgings, for instance the Chrysler 6.123" rod would certainly come from the same forging as the Chevy 6.125" rod, with slightly different big end detail.

Their rejection rate would be too high if they didn't have over 0.30" width to machine off in finishing.

The 6.0" rods for the Chevy 6 are fully 0.11" wider in the big end than the V8 rods, but are otherwise dimensionally similar. That's more than you would expect might be possible from specific forgings for rods of the smaller size, but I'm talking about a mere 0.030".

It sounded fishy to me also Ray, but the rods I was asking them about was their Big Block Chevy forgings which are 1.00" wide and only .050" smaller on the OD per side of the housing bore for use in the 292 6 cylinder which is also 1.030" wide. As they said it simply could not be done. They said that after doing this for 40 years they have learned to refine the forging dies to the point where they can get them made with less metal waste and less cost, and that all their raw forging were only about .010"-.015" smaller than the finished inside housing bore and that the widths were only about .010" wider than when finished.

I'll go talk to them in May when I get there...