4.6 daily driver

[buschguy]

I'm hoping to build a dependable stroked daily driver. I calc'd using a 258 crank, 4.0 rods, a stock cam, 0.043 gasket , 24cc dished diamond pistons, deck milled 0.010 and 3.905 bore a SCR of 9.26:1 a DCR of 6.83:1 and a 0.052 quench. Should this be able to run on 87 octane at sea level. The pistons are $$$ so I hope so.

[dwg86]

How much are the pistons going to cost? Why not use the KB944 pistons?

[ajmorell]

The diamonds are a little bit more than the KB944s, but they also have a little larger dish dropping the CR a bit. I dunno about running that on 87, 89 maybe.

[gradon]

The KBs still require you to deck the block .030" to get a zero quench(due to the 1.353" comp height, which is kinda lame, esp since that height is perfect for using the 6.150" eagle rods, which can't be used on the KBs since they aren't floating pistons). The custom piston route might cost a little more(maybe $25-100 if you're paying $475 for the KBs, even though I recall someone who paid a little less than $500 for their customs), but you can get the dish you want, a 1.38" comp height(no decking costs now, so figure that in), and maybe a higher quality piston(have heard nothing but good about Diamonds).
I didn't see that it was you dwg that was questioning him not choosing the KBs, but maybe others don't know why the KBs aren't "the" optimum stroker piston, but are an option.

[buschguy]

From what I've read the magic numbers for 87 octane are a SCR of 9.1:1, a DCR of 7:1 and quench between 0.04 and 0.06. My SCR would be just a little higher. The diamonds have the deepest dish I could find without having some custom pistons made. I don't want to spend all this coin, only to have to use 89 or 91 once gas is back up to 4 bucks.

[Heck]

I'm running the kb944's now, 21.7 cc dish, with a less than optimum setup. The pistons are mounted backwards, thanks to the faulty instructions that came with the pistons, but the quench on these pistons is small, almost the same size on both sides. I also didn't deck the block, only .018" below deck on my block. At 400' above sea level, I don't have a bit of ping, even with the short duration "RV" cam I run (240 deg). The pistons were top quality stuff, looked like jewelry. If all you're worried about is ping, there's no point in spending more money. For other reasons, such as what gradon mentioned, you would want to go in a different direction.