Is it possible to get 400hp, if not then close to that number, out of a 4.7? I have an '04 Jeep GC currently with the 4.0 but I'm considering droping in a 4.7. I've heard it can be done, and I've also heard it can't be done so I'm here to find out. The 4.7 is the only engine I want in there and I don't want N/A. With that said, is the 400hp mark actually possible? If not, then what's the most I can get?

 

Anything is possible with the right budget.

 

What kind of budget are we talking about here?

 

1. 4.56 GEARS - depending on your tire height 410's/4.56's. Personally if your tire height is taller then 30" tall I would lean towards 4.56's.
2. ELECTRIC FAN -.
3. 2008 INTAKE MANIFOLD or our SULLIVAN ALUMINUM INTAKE MANIFOLD -
4. 4.7L PERFORMANCE CAMS - H/O's, 206's or 212 Cams
5. SUPERCHIPS FLASHPAQ - Great with up to 70mm throttle body and H/O cams.
6. HEADERS -
7. SINGLE 3" EXHAUST -
8. HIGH FLOW "Y" PIPE & MUFFLER -
9. 70-72MM THROTTLE BODY - F&B. Chose the largest Throttle body you can tune for. (70mm for Superchips & 72mm for SCT custom tune)
10. RACE PORTED HEADS -
11. CUSTOM PROGRAMMER - SCT CUSTOM TUNE (Needed with PORTED HEADS & or 206, 212, 212x, 218 or greater custom cams & or 72mm throttle body)
12. 2800 STALL CONVERTER - This will get you off the line quicker by allowing your engine to rev to approx 2800 before the transmission engages... Under part throttle would would not notice much of a difference at all... but put your foot down and the RPM's will rocket to the desired RPM getting you closer to your RPM power band.

You can google the prices yourself but I would guess $3000-$4000 and that list will probably get you maybe 100hp over stock, still not 400. Maybe with a 50 shot of nos on top of that you might get there.

 

I like all those ideas! I would rather stick 4.10's (closet I can find for a Dana 35 is 4.11's) Since this will still be somewhat of a daily driver. Also, what about a meth injection from Snow Performance? Will that benefit me at all? And what about the converter, would that some of the driveability out of it? Thanks for helping me out!

 

The Sullivan manifold will not fit on a Grand Cherokee without modifying or replacing the hood which I would prefer not to do. Also, do I need a higher stall converter if I get 4.11's or vice-versa?

 

I was considering this myself and the only place that makes the parts to do this is airram.com. they have ceramic coated Ross racing pistons and race prepped heads with nitrous injection prep if you really wanna go fast. You can also get an intake manifold machined to bolt an m203 supercharger so if you do add nitrous injection you can still boost it in higher RPM's unless your willing to attempt twin charging (possible but this motor won't get enough out that to be worth the trouble) after that you can get axles from eastcoastgearsupply.com that will bolt right on and can handle the power, definitely won't wanna leave that weak Dana 30 they use for the front axle if you go too big. 4.10 gears are good enough but you'd wanna swap your driveshafts with bigger custom made ones, I got one from woody's and they are much greater than stock. You'd need to upgrade the internals in the 545 RFE which can be built up to 500 hp or more because they use that transmission in dodge vipers. After that np247 transfer case should be OK but may need to be swapped with something more heavy duty. But I called them and they told me about 10K worth of engine internal parts should get you 500hp and the drive train might be ok for a while depending on driving habits. Headers won't make enough of a difference to be worth the issues it'll cause with emissions and oxygen sensors being weird because that jeep is finicky with sensors. I used magniflow high flow exhaust from manifolds back and it gets about the same amount of flow you will with headers and passes emissions no problem and sensors work perfectly. I'm probably gonna be good with heads and pistons which is only 3 grand to get mine in the same league as a hemi but there are alot of options with that vehicle.