Fastest jeep 4.0 1/4 mile ET w/picture

[KenoshaComanche]

I'm going to make a pretty bold statement here.

I think I may have the quickest N/A "stock" 4.0 jeep..

Stock meaning:
Crank/rods/pistons
Heads been rebuilt but no porting polishing etc
log style intake
throttle body
Near stock C/R 9:1
Running race gas
With an aftermarket standalone accel ecm
Long duration, stock lift cam.
With a torqueflite 904 and a trans brake.

With this combo in the 1/4 we've run 13.28 @ 100mph

Then we bolted on a 62mm throttle body
And we ran 12.94@101mph

Then we gasket matched the intake manifold and did cleaned up the runners and plenum but kept the 62mm throttle body

And Ran a [email protected] with really shitty weather.


Oh and by the way, this is not stripped either. It weighs 3200 with me in it.

I am looking to see what other 4.0 and even stroked motors are running in the 1/4

Let's see what you guys have got!

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[dwg86]

That's Awesome! What gear are you running? What RPM'S at the end of the track?

[KenoshaComanche]

Right now we're running a 5:13 gear, and I'm at about 6800rpm through the lights.

I'm really curious to see were the boosted and sprayed strokers are at with the e.t.'s I'm ecstatic at how this n/a setup has turned out.

[gradon]

Nice engine bay(and mj).

[Cheromaniac]

I'm at about 6800rpm through the lights.

On a stock bottom end? You're brave!
How is the engine still making power at that rpm?
Your engine bay looks very clean but I think there's one little detail you neglected to mention (like a nitrous kit).

[KenoshaComanche]

Haha thanks, we've always run it that high into the rpms. In 2014 we ran a 5:38 gear and were going through at about 7100... The cam is the critical part which allows us to still make power up there. And nope lol no spray or any power adders.. all motor!

[KenoshaComanche]

If your interested in more details and looking a bunch more pictures to kinda get an idea of what the truck is. Go on Facebook my page is Seitz Racing Team. There a lot of great pictures an info on there about our setup. And I have a YouTube page too that shows this little motor going through the lights at 7000. The page name is KenoshaComanche

[dwg86]

Are you running a gear drive or timing chain. I've heard that the amc 6 has some sort of weird harmonics going on around 6000 rpm's that breaks chains.

[KenoshaComanche]

Ive heard the same thing but have yet to experience any consistent issues. We're running the stock style single chain. Im no engineer but thinking about it I wanna say that the harmonic thing only happens when hanging out in the 5800-6500 range, but since we're powering through it and not peddling it persay like in road racing or rally style racing that we don't experience that issue. We had one camshaft shear/break on us but we chalked it up to it being very long and cast, having alot of runs on it and very high spring pressures. Otherwise since 1990 we have never had any issues other than that once instance

[KenoshaComanche]

And that one instance where the camshaft did break was the same night we were running brackets at the dragstrip and I was peddling it at the top end of the track.

[dwg86]

What valve springs and lifters? Are stock valve springs and hydraulic lifters getting to 7100 RPM'S?

[KenoshaComanche]

lol No the lifters and springs aren't stock, I'm running comp springs with 160lbs closed and 380lbs open. its a bit on the high side but it works for our application and we haven't experienced any issues. and we were running comp cams pro magnum hydraulic flat tappet lifters but we decided to switch to crower solids to ease valvetrain adjustments. when we were in the 13.20s we were still using the stock rocker arms but in the last year or two we switched to yella terra roller rockers with smith bros adjustable pushrods.

[dwg86]

Still an amazing ride. Getting into the 12's with a stock bottom end, 242 cid, 6 cylinder @ 7000 rpm's...I love it!

[KenoshaComanche]

Thanks dwg, I'm still interested in what kinda times other people are running. I don't care if it's slower, I just kinda want to get an idea of where I'm at in comparison and to let people brag alittle about there project!

[Cheromaniac]

Mine's slow by comparison but I use it as a back-up daily driver and it has stock 3.07 axle gears plus a stock 5200rpm rev limit.
I have a 2006 Mustang GT to fulfil my need for speed and that does a 12.67 @ 108.61 1/4 mile.

Oh and by the way, this is not stripped either. It weighs 3200 with me in it.

Mine's 3620lb with me in it and 1/2 a tank of fuel.