4.0 mod question

which way to go....motor is from my '94 explorer for my '86 bronco II......should I go with stock pistons, 410 cam and ported 95tm heads....or OHC pistons, 410 cam and open chamber heads......also will these mods require an ECM "tune".....thanks in advance

i'd bore it out .30, maybe a higher comp ratio, im not sure what stock is. cam suited for the kinda terrain it will see,higher lift the better, i say pretty much go all out with it while u are doing it, parts arent too much more then replacement.

It's generally agreed that the 4.0 is a good engine for the Bronco II and the RBV's as a whole, particularly for DD and off road use because it makes good torque at low RPM's that's not to say it doesn't have it's short comings. After all the reading I've done it's my humble opinion that the short comings are from trying to comply with federal regulations and in doing so the engineers missed the potential of this little motor. To get the most out of the 4.0 I don't think you need to reinvent the wheel, just make it more efficient. The #1 most agreed problem area is the heads all suck specifically the exhaust ports and that a good port job and headers is the best way to spend your money to wake up the motor. Everyone suggests using aftermarket castings regardless of which heads you use. It seems that the 97tm heads produce the best results. Increasing the compression ratio to 10:1 is another popular modification most commonly achieved by either using 97tm heads on pre95 motors (dished pistons) or SOHC pistons (flat tops) with 93tm heads. I have read that the pre95 motors with 97tm heads (fast burn chambers) will burn up if you use an ECM out of an aerostar, not sure if same is true with explorer ECM. Timing components are one of those things we have to deal with. The stock lifters work fine but their design makes the susceptible to dirt and crud so use quality oil and change it regularly. Rocker arms and push rods are another story and the forums are all over the place on this but i see 3 choices, #1 the stock parts....perhaps not the best design and a lot of noisy valve train complaints but I can only speak of my own experience, my 94 explorer has 197,000 miles and runs without a tick. #2 stock but have the push rods and rocker ends hardened. #3 use "deltacams" set up, I have read where they can be hard to deal with if you don't get both the rocker arm assembly and push rods from them. Camshaft...3 choices here as well, stock and the two offerings from comp cams. Ford may ave missed the mark here. Most say the 410 from comp cams should have been the stock cam from the get go and is the best "overall" choice, they also have the 422 cam reported to have better performance but may cause driveability problems in automatics. Both comp cams require the use of after market push rods and it's recommended to use their dual valve springs. stock intake, plenum, MAF and injectors all seem adequate and while you can port match the upper and lower and use larger MAF the cost (time/money) seem to out way the gains.

sorry for the long winded post but I'm more or less writing out my options as I see them to "build a better mouse trap"

I welcome any input, opinions and/or advice other than go V8 as that's not my goal