I am building a stout moter, It's a Dart Little M with a 4.185 bore, 350 Mains. I am going to be installing a 3.875 Stroke 4340 350 main crank for 6" rods, I will also be using 4340 H-beam rods, and 20cc reverse dome pistons for 3.875 stroke and 6" rods as long as the deck height is 9.025 or something.. So I have been looking at my rod length to stroke ration.. 3.875/6.0 = 1.55 is this good or bad? Reading John Lingenfelters " On modifying small-block chevy engines" he speaks of a favorable 1.9L/R but on a stock chevy 350 the L/R is 1.64 and on a stock 400 is 1.59.. I'm just a little over the stock 400, will this have any negative effect on my engine or bearing life? extra skirt might be needed to prevent rocking in the bores..?? Need to know some negatives..

 

You need to do a "search" of past posts on this forum. This is a fairly popular subject, and has been discussed in detail several times.

If I can take the liberty of distilling the posts to a simple statement, I would say the conclusion is that rod/stroke ratio is relatively unimportant in anything other than an all out, extreme race motor.... at least within the limited number of choices for the SBC. Most people seem to feel that piston strength/wrist pin location/ring placement takes priority.

But read the posts and see how it fits your needs.