Jeep Strokers

Ande1879,
I wasn’t recommending either, just pointing out there’s 2 choices:
1) 4.0 block, 4.2L crank, 4.2L rods, 4.0 pistons with stock compression height
2) 4.0 block, 4.2L crank, 4.0L rods, off the shelf(KB424C, IC944) or custom (Russ P) pistons with 4.0 bore and shorter compression height.

Both choices have pros and cons. I chose option 2 with a 98 4.0 block, Scat 4.2L crank, Scat 6.125” (4.0L) rods, custom short compression height 4.0 pistons.

TJBUD

ande1879 wrote: ↑March 5th, 2023, 6:22 am That’s the route I believe I am going is 4.0 rods. I just haven’t nailed down what pistons yet? I’m open to suggestions. And I definitely want to do what is needed to keep compression low enough to run 89 octane

I suggest you opt for a set of Russ' custom pistons. They come with a compression height of 1.385" and, when combined with the 4.0L rods, the piston crowns will be 0.005" above the deck so you won't need to have the block milled, thus saving you that cost. The quench height will be 0.038" when a 0.043" thick head gasket is used.

Russ also stocks a modified version of the CompCams 68-232-4 cam with a lower valve lift that allows you to retain the stock valve springs.

Does anyone have a reason that the KB424C pistons don’t works well? Using them with the 4.0 rods and decking the block .010. I noticed that’s what clegg sells in their kit. Keep in mind I’m not planning adding a turbo. Thanks

Here’s a thread on KB424C

Pasted this time
viewtopic.php?t=6252

Can stock 4.0 rods be bushed? Estimated cost?

Brianj5600 wrote: ↑March 6th, 2023, 9:21 pm Can stock 4.0 rods be bushed? Estimated cost?

I don’t think it’s really cost-effective to bush a stock set of cast 4.0 6.125 rods

By the time you pay your machine shop to press your old pistons off, resize your rods with a set of replacement 11/32 ARP rod bolts, check the end to end balance, and then pay them to reinstall your new set of pistons you’ll easily be within $75.00 to $80.00 of my bushed steel rods.
Another design upgrade to my rod is that unlike the stock rod that locates its cap by the neural on the rod bolt, my rod caps are located by pair of stainless dowels held together by a set of ARP 8740 3/8 cap screw rod bolts.
Currently the cost of my rods are $388.00 a set.

Regarding my Pistons I sell/stock both .030/4.6 and .060/4.7 pistons with a 12cc dish to a 28cc dish in 2cc Increments making it much easier to target an exact static compression ratio. With the compression height of 1.385 this gives you a choice for budget considerations not having to go through the expense of surfacing the deck of the block in order to maintain a tight quench.

Keep in mind that virtually all of the other piston options require the block to be decked approximately .030. If you go with the short rod stock 4.0 piston route you’ll be stuck with a high static compression ratio and poor quench.

Welcome to reach out to me and I’ll be happy to forward you more detailed information and pricing.

Thanks,
Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Cell (626) 673-2203
Email: [email protected]

What’s your alls opinion on cam selection CompCams 68-232-4 vs 68-235-4. And if I go with the 235 what valve springs? Russ I heard somewhere you have a custom grind 232?