Offset Grinding 292 Inline 6 Crank Rod Journals

[enigma57]

I have a question regarding offset grinding crank journals......

I have one of the 1963 forged steel cranks for my 292 inline 6 build. Also have one of the later model nodular iron cranks with 12 counterweights.

The long stroke, tall deck 292 6's are prone to harmonics issues at engine speeds above 5,500 RPMs. So I have been thinking about offset grinding the crank journals to destroke it a bit. Stock stroke is 4.120" and journals are 2.10", same dia. as 350 V8, only the inline 6 rod has a wider big end (1.030" versus 0.940" for small block V8 rods).

I have heard of these 292 cranks being offset ground for the short deck 230/250 blocks using 5.7" 230/250 inline 6 rods which have 2.00" dia. journals same as a 283 or 327 V8, but as with the 292, wider on the big end.

However, I am interested in offset grinding the throws to fit some used Carillo NASCAR type rods that utilize smaller 1.850" journals. I have seen them with big end widths varying from 0.820" or 0.900", but none as wide as the big end of the stock inline 6 rod.

The reason I am considering offset grinding the rod journals for smaller 1.850" dia. bearings is that I would like to destroke the 4.120" stroke crankshaft to 3.875" and also reduce the counterweight dia. to lighten it. 0.040" overbore along with a 3.875" stroke would be close to 280 cu. in. and I believe the reduction in stroke would go a long ways towards minimizing harmonics issues at higher RPMs.

Is this doable or would you advise against it? Engine will go in my mostly street driven '57 Chevy which will be run at the track from time to time mostly for tuning.

Thanks,

Harry