Running 87 octane fuel.

[Shooter77]

Hey guys, first post. I'm building a 4.6 for my 99 Cherokee that I use as my hunting rig. The current 4.0 runs fine, starts every time and has never left me stranded. ( I still carry a crank position sensor around, I'm not going to tempt fate.)
It's got 280k miles on it, and the jeep has picked up about 560 pounds in mods since I bought it. I drive it all over the country to hunt, and at this point when I'm driving through the mountains I'm struggling to maintain the speed limit unloaded, when loaded it's just not happening.
I have three goals with the new engine. Run 87 octane fuel, get around 15mpg, and maintain 70mph up a 5% grade without dropping to 2nd gear.
My block is at the machine shop getting bored to.030 over and decked .020.
I ported a TUPY head to a fairly close match an early 0331 head, and I'm about ready to order parts.
Does anyone have a similar combo that got the results I'm after?

[dwg86]

If you use an earlier model cam, make sure you use a spring and pin and valve cover from an earlier engine (up to 1998). I’d use the correct cam made for the 1999-2006 Jeep. SA Gear sells a double roller set for the 1999-2006 cam(Rockauto.com). You can use stock springs up to .450 lift. Anything above that you’ll have to find a spring that works. If you’re not turning rpm’s over 6000 rpms(well you can’t unless you up the rev limiter in the ecm tune) and want your cam to last. I’d keep the seat pressure below 100 psi and open pressure below 250(I’m no expert engine builder so confirm with your machinist and some research).
I think I found a spring/valve spring retainer to use with a cam over .450 lift. Once again verify with your machinist. comp camps springs part number 26903-12 are good for you to .550 lift and are 95psi installed at 1.650. You’ll need dodge 2.2/2.5 valve spring retainers Melling part number VSR-513-S to work with those springs.
If you’re looking for a custom grind cam, good luck. Most cam companies don’t have to later model cam core. Comp cams has 2 different 1999-2006 on the shelf cams and they are available. Howard’s cams has 1 grind (p/n 320111-12) it’s similar to com cams.
Use ONLY MADE IN USA lifters (hylift-Johnson). Howard’s cams and bullet cams sells them. Eagle sells a 5140 forged connecting rod for under $300. I’d buy those before I had stock rods reconditioned. Scat sells 4130 forged rods. They are a bit more expensive.
I built a stroker years ago that had 9.5 static compression. It ran fine on 87 octane. You should be fine with a tight quench.

[Shooter77]

Don't need anything special, just need enough power to stay ahead of the speed limit in the mountains while dragging around way too much gear and not paying through the nose for fuel. I hunt deep in places far from roads and I'll drive a long way in the highway to get to places where I have to go a long way from the pavement. Probably going to drive it to Alaska next year.

[75SV!]

I haven't been successful. Still, I have the same goal, if that helps. I do have a mini stroker running, but a severe misfire. I do have a Russ Pottenger 4.6 sitting in my kitchen. Waiting to go into my '88 Comanche. Also, an LS build going on.
I have done 3 4.0L heads. Still learning. I did do the Mini on a 2000 block. I had Schnieder regrind a cam to .450 lift. Watch the springs if you go stock springs. There is a difference in lbs at seat between the 2000 and '95 springs. I'd look at Melling Springs for a '95 HO. Gives 85 lbs at 1.640. Also, Why did you not do the 99 heads? I did two of them. LS valves. The Melling springs and the stock retainers should work. I went with Sealed Power springs (from Russ) and Chevy SB retainers. That was with SCB valves.
I also, don't know why you are decking the block .020. I would think for a Poorman's Stroker. I am look at the Keith Black pistons, next time. They did the 'D' or stock depression on the top of the piston. Also, 9.3 CR. For rods, I'd go Scat. I'd compare price as to reworking a set of stock rods.
I am looking to port a TUPY head. Mainly, I want to do a 'D' exhaust port like a Chevy head. I also, did 30 degrees valve seats on the intake. Not sure if and how they will work out.

[Shooter77]

I decked the block .020 because I'm using the Cleggs stage 1 kit. without going through the math that's the simplest way to get to a .044 quench height and end up with around 9.3-1 compression. I want a little bit of a buffer for varying fuel quality running 87 octane.

[75SV!]

Not sure what part of the country you are. I have a place in WV. So, 5% to 9% grades are in the travels. Even some hairpins. I way OK with a stock motor, bore TB, header and 2.5 exhaust. Also gearing. I was getting around 17 mpg. That was with 31's and 4.10s. I did get 18 to 20 mpg on my 2000 XJ with 31's and 3.73 gears. Not sure what I did on it, as I went from 17-18 mpg. I change to synthetic in the front differ. Added the window aero vents and did a cut and fold on the rear quarters. Then shortly after that #6 piston skirt cracked off.

[75SV!]

I looked at the specs on the KB424C piston supplied with the Clegg Stage 1 kit. It has an open or circular dish. Might cause quench problems. See if others have an opinion. Also, looked at Cleggs stage 1 camshaft kit. .453 lift. Says stock springs. I'd used the Melling springs for a 91-95 HO. Should be about 85 lbs at closed height. Also, a bit thinner diameter wire than stock. So, less coil bind. If you haven't purchased the Clegg kit, might look at Dino's page for a 'Budget' Build. See what pistons he used. I think just stock 4.0L pistons. I'd see if a 2000+ piston would work. They have coated shirts. I used them for my Mini-Stroker build.

[Shooter77]

Cleggs kit is already coming, using their stage 1.5 cam kit. (not up on their website yet, I called and talked to him and that's what worked best for my requirements). I'm running 33's, 410 gears (which ends up coming back to stock final drive ratio almost exactly). I drive all over the country and through mountains almost every trip. I'm just looking for decent mileage, cheap fuel and enough power to handle the long uphill grades at normal highway speeds. My budget for the build was $4000. With parts, machine work and nickel and dime expenses I should be under that.