Chrysler 3.3/3.8 build ideas

I haven't been able to find much information on building up a nice streetable engine with one of these, but I have heard that a Jeep 4.0 liberty crank will fit in the block. Any ideas on what heads would be the best starting point for some serious porting?

I don't think you'll make much power (200+ whp) for the money you spend building it if you don't make a turbocharger the centerpiece of the build.

I've heard that the Mopar engineers had trouble with the engine's living under "moderate" boost levels. Of course these were Mopar engineers, so moderate may have been over 15 PSI, lol.

The 2001-2007 3.8's made 215 stock, It shouldn't be too much of a stretch to see 300 naturally aspirated.

Is there some reason a 3.5 wouldn't be used instead?

In reply to pres589:

Not a good one, I just like pushrods in this application.

I'd be very curious how you plan on making 300hp with a 3.8 without boost or NOx. Custom camshaft seems like a requirement and at that point, why not build anything else?

In reply to pres589:

I've already built the transmission with extra kevlar clutches, shift kit, diff pin retainer and aftermarket converter. I've put over 100k of really hard miles on the vehicle in the past year or so without a single engine problem. Now that there's nearly a quarter of a million miles on it it will probably need some attention soon, but I'd rather take my time and build one on a stand to swap in.

I'd make more power and get better mileage from an entire SRT4 swap, but I am a little weird.

Oh boy... The 4.0L V6 is just an enlarged 3.8....... You can't boost a 3.3/3.8 a lot because of thin decks. 3.3's have different chambers then 3.8's, but I can remember which way. Port wise, all the heads are the same.

You're doing 100k miles a year??

And you want to do what again?

Aren't these V-6's ? Installing a Cherokee crank would be difficult.

There's a 4.0 v6 available now, not the venerable online six

Oh boy... The 4.0L V6 is just an enlarged 3.8....... You can't boost a 3.3/3.8 a lot because of thin decks. 3.3's have different chambers then 3.8's, but I can remember which way. Port wise, all the heads are the same.

Reference for thin decks? Prove it. There's lots of 3.3/3.8 threads out there and ive read most of them. Never seen anyone post an ACTUAL, REAL number regarding any kind of sonic check or a cut up motor to see what's what..

Also, the 4.0 is not an enlarged 3.8 as much as it is an enlarged 3.5. Its a sohc, 24v top end. The original 3.5 used the 3.3 stroke and 3.8 bore. All 3.3 and 3.8 are ohv 12v motors.

Heads did change around '00, not sure on the specifics. Manifolds changed with them. There's several varieties of intake and exhaust manifolds but none of them would be ideal for 300hp.

As for getting 300hp n/a out of a 3.8.. you need more rpm first and foremost. But considering the can-am 3.3's made 255hp (rumors it was detuned) revving to ~6800 on stock valves and valvesprings on the earliest (worst) heads with .5L less displacement all the way back in 89 or 90... suggests it cant be THAT hard to make an extra 50hp with the same or better parts and an extra .5L.

As for my 3.3/3.8 stuff.. I have a 3.3/604 car with a pile of parts sitting around for it.. including a t4-t67, AEM FIC, ring and pinion set, transfer gear set, Autostick tcm, and of course there's plenty of stuff i havent bought yet for it.. like the 3.8 shortblock.

Bottom line: figure out how to get it to rev and shift higher first (shoot for 7k imo). If you cant figure out a way to move that rev limiter.. you might as well give up on any 300hp n/a plans... For anyone who doesnt know.. the 3.3/3.8 WOT upshifted at 4800-5500rpm depending on the app.

I was running around 100k a year visiting family on the east coast on weekends, haven't done that in a few months and won't be more than a few times a year.

I'm just in the planning stages right now because I foresee needing to do some serious work on the engine soon. A quaife or other street friendly LSD would be the biggest improvement in putting power to the ground right now. Even with the stock engine I'm smoking a tire if I'm not pointed dead straight on a dry road.

I'd be happy with HP over 215 just because that's what the old 5.0 mustangs were rated at, 300 just sounded like a good target from 4 liters.

IIRC you can adapt a quaife or OBX helical torque-biasing diff from a neon or k-car into the 604 trans if you make a spacer for the ring gear and massage the stamped steel diff cover for clearance. The axle splines and diff bearing diameters, overall carrier width, etc are the same.

These threads give me bad ideas....if I someday end up acquiring my moms 3.3 caravan.

In reply to failboat:

OT: That is why the other thread was posted.... Soon the wife will want a different ride, so the Avalanche will be MINE... Then out comes a T76, convert to SD, built trans by me, lowered 3" or so, etc.....