Need to order pistons

[Rob92XJ]

I'm starting my stroker build and have read through a few threads but still don't know just which pistons would be my best choice. I'm planning to keep the 4.0L rods, boring the block .060 over and using a 4.2 crank basic stuff. My problem comes with wanting to keep the Jeep running on 87 octane fuel, so do I order a set of Keith Black 944s or is there a better choice to help keep my CR low around 8:1 or 9:1 the highest. The cam I have is a Mopar Performance cam I don't have the specs with me but it is the stage 1 cam.

[dwg86]

If you are going to use the 6.125 4.0 rod, the KB piston is your only option unless you have a custom set made.

[Mgardiner1]

You'd probably be better off using the shorter 4.2 rods and not decking the block, should give you a much lower compression and no problems on any pump gas

[Rob92XJ]

A friend of mine used the shorter 4.2 rods and didn't deck the block or have anything done to his head and he has to run 89 or higher or he gets sever spark knock at lite cruise and heavy acceleration. Besides I have to be different then him.

[Mgardiner1]

What pistons and camshaft did he use?

I get spark knock out of my stock renix sometimes, but i blame it on a timing issue with my front damper CPS kit and the wire being too high of resistance

[seanyb505]

You could get the shorter 4.2 rods, Silvolite 2229 and have them dished out so you can deck the block and not run into compression ratio issues. Or get the KB or custom pistons to run the 4.0 rods.

[Rob92XJ]

What pistons and camshaft did he use?

I get spark knock out of my stock renix sometimes, but i blame it on a timing issue with my front damper CPS kit and the wire being too high of resistance

The cam is actually the same cam since we work as techs for a local Jeep dealer we get Mopar Performance parts at cost. The pistons he used were a Speed Pro stock replacement piston.