Thanks to the internet, I have learned about big end widths, why perfromance rods are thinner and how to accomodate a thinner/lighter rod. That said, I have located a set of 6.200 SBC small journal rods for my S-10 stroker. I will be turning the stock marine crank down to fit the rods. I will be looking to see what piston/comp. height I can locate, before I do the crank work.
Now you are on the right track....... well maybe!?
Since it sounds like you are still going to use the 1.035 width rod journal crank you must be planning to use "Piston Guided" rods? You can go that route if you want, and yes it will work, But before I would do that I would try and find the "Really Late" marine crank that is "supposed" to accept stock width SBC rods and start there. Also are the 6.2" rods that you have located designed to accept the std. .927" wrist pin? If not you will end up spending "Big Bucks" on custom pistons. Many if not most of the 6.2" used "Nascar" rods on Ebay are designed for the .866" or other "odd" sized wrist pins...... beware! But remember though you will be spending a lot of money on the special machine work required to fit that crank into the Duke block and to accept the Duke flywheel. And when all is said and done are you going to trust it??????
Read post #63 again for a little more rod length vs stroke info.
The Duke has a deck hieght of 9.175"+ or -. Don't deck it more than absolutely necessary as it is very thin to start with and make sure the machine shop uses a torque plate when they bore and hone it to maintain cylinder wall concentricity. Very important with the Duke block.
Included are some photo's of my 3.42" SD4 crankshaft/pistons/rods for my Duke block. I just picked up the parts from the machine shop yesterday. It is a true SD4 crankshaft stroked (from a 3.25" version) to 3.42". It is ground to accept a std. 1.889" (Quad four/Nascar) journal rod bearing. The rods are 6.2" Carrillo's (SBC width) and the pistons are Keith Black .030 over Hypereutectic.
Now to make you really drool;
I have, still in the GM crate, a brand new 3.625" stroke SD4 crankshaft. After selling all of my SD4 stuff last year I saved it as I was not sure at the time which crankshaft I was going to use for my "Last" Duke stroker engine. I chose to use the 3.25" crank and upstroke it to the 3.42" rather than destroking the 3.625" crankshaft. When I finish the engine I am building now I will sell the 3.625" crank to the highest bidder on Ebay. The bidding will start at $800 unless someone makes me an offer....... that I can't refuse!