Funny how things just happen to get printed when your trying to come up with a new combination. I have been researching how to get a 4" stroke in to a production block . Since GM has been putting 3.800" cranks into late modle blocks with 2.10 rods , Whouldn't it be just as easy to go witha 4" stroke and reduce down to a 1.88(honda) rods bearing size rod for clearance. I have gone through Eagles cataloge and it appears they have off the shelf parts to put this kind of motor to gether. Any info from anyone else would be great.  

An engine like that, I'd be worried about reducing the bearing size that much. Honestly, you'd be better off going with an aftermarket block with better strength than a stock block. A 383 is one thing, but a 408 is another, adn odds are you're not gonna be gentle to this engine, so you want as much strength as possible.  

I dont think strenght is an issue look at what some of these guys are running in pro stock motors. This is goingt o be a street motor with a little bit of pressure via turbo , and a rpm limit of 6500. Plus anyone can get 400 + cid from an after market block. The cool part is doing it with what I already have.