Stroker 340>416 Build Advice
I wasnt specifically planning on zero decking the block but like I mentioned the machinist will have to deck a currently unknown amount to remove some gouges that are on the head surface (was there when I bought the block unfortunately).
Here comes another newbie question: based on internet search a stock 340 had a -18 deck height (the top of the piston was above the deck) when Im getting this engine built is that a value that be changed? In my head the crank and rods set that pretty much in stone based on the fact Im getting a kit.
So if I understand dynamic cr it can be used to help a higher static cr engine have less chance of detonation? So a cam with higher durations will lower dynamic cr right?
True, high compression 340 pistons were proud of the decks, your stroker package will have pistons, that unless the block is zero decked, will be some measurement down in the hole. This scenario alone, closed chamber with dished pistons vs. Open chambers with domed pistons, is much less sensitive to detonation due to better flame propagation, and less hot spots on piston faces.
You are correct about longer durations causing less dynamic compression, lobe seperation angle also contributes to this. This is why my cams have 106LSA, to trick my engine into thinking it has a little more compression than it does, also factoring in my 3000ft elevation. The narrower LSA helps to build more cylinder pressure. This is why I suggest speaking to a cam grinder and having one tailored exactly to your combo. All of these factors will be addressed.
You are getting good advice here from guys that know a lot more than I do. I think the general theme here is buy BEST parts you can AFFORD realistically, make a plan based on expected outcome, execute the plan. All of your choices have to work together, when all parts of the build compliment one another, you will have a winning package.
Ps. Maintenance on solid flat tappet cams is very minor, and should not be a deterrent in cam choice. Not trying to sway you, just giving facts.