75 HP is a lot of difference between a couple of years and same basic design. I see there is a compression bump from 9.3 to 9.5 but that can't be all of it...so where's it hiding???
Software, cams ???
Thanks
Curt

That's a great article on the 4.7 I have to admit that I was a little skeptical when it first came out. The 5.2 had been around for years and had proven itself a strong and dependable powerplant. My dad bought a new Dakota in 2003 that had the 4.7 and he hasn't had any issues. I bought a 00 Durango a few years back and have been pleased with the 4.7 It REVS great and with the help of a 50 series Flowmaster muffler and Ram Air intake it sounds mean too. I'd like to see someone build a real mean 4.7

The few Ive driven didnt feel like any more power than the previous sngle plug 4.7

C&P from the AllPar link above:

In 2007, Chrysler replaced the 4.7 liter V8 with a new version. Power went from 230 hp to 290 hp (and up to 320 lb-feet of torque) with that move; gas mileage went up, and noise and vibration went down. The new 4.7-liter V-8 features 5.7-Hemi features such as two spark plugs per cylinder, with a high 9.8:1 compression ratio, and better port flow; but it has a new slant/squish combustion system design.

Refinements included significant revisions to the induction system, reduced reciprocating mass via a lightweight piston/rod assembly, and reduced accessory drive speed. A new normally open valve lash adjuster system smooths the engine at idle, while electronic throttle control is needed for new stability systems. The engine will be manufactured at the Mack Avenue Engine Complex in Detroit.

Rick

i understand that the two spark plugs in each cylinder are not the same design, and even call for replacement at different intervals

anyone got the inside scoop on this?