our plans are to stroke a 396 using the 454 crank trying to figure out if we use a 396 style rod or use the 454 rods to add for the extra stroke?

Aren't all BB rods (stock) are the same (same length)?

Its the pistons that have different pin locations, depending on stroke...

Just went through this whole deal. Keith Black makes a piston with the correct compression ht. For info go to www.kb-silvolite.com. (http://www.kb-silvolite.com.) Piston is listed as Chev 434. Uses stock GM 6.135 rod and 454 crank. You will have to have the assembly balanced and the 396 block will require a fair amount of grinding to clear the crank counterweights. After exploring this, adding it all up, including bore/hone, cost of crank, balance, new balancer and flexplate- I said to heck with it and stayed with my .030 over 402. I had checked around and spoke to KB direct - the pistons are not in stock in any overbore, best estimate for delivery was sometime in March. If you have an early block, I would suggest stay with the stock 3.76" stroke and bore out to 427 size. If you have to do a lot of work to your block in the process {decking, cam bearings, line hone, boring} and you want the longer stroke motor, I would strongly suggest you set the 396 aside and get a 454 block to work with. I my case, the 402 based block had already been decked and line honed - we kept the same pistons, so all we needed was new rings. The estimated tab for the pistons, crank, additional machine work, parts, etc., etc. was about 1000.00. For a gain of 26CI, 1000.00 is far too much money for that gain IMHO. Good luck.