XJRunner said:
yea no stroker. I just want more power. I just want to know all the little power secrets. injector swap, cam,intake swap. I want more low end and mid and top if possible but it don't matter as much
You can't usually have it both ways - either top end horsepower, or low-end torque. While an increase in one will net you an increase in the other, you're going to target one or the other more.
Since the inline six in general (and the AMC six in particular) was designed from the ground up for low-end grunt, focus on that. Besides, when you're cruising or trying to get moving, it's low-end torque that will do that for you.
Here's a question - do you have an automatic or a manual? While an automatic is geared fairly well (3.54/3.55 from the factory,) it could benefit from a bit lower gearing - like 4.10. If you've a manual, the gearing (3.07) just plain sucks - someone wasn't thinking. Going to 4.10 or 4.55 could net you a noticeable improvement in performance, and it's an easier job.
There are a number of camshafts that fit in the AMC six block, but many of them are listed as "not for use in computer-controlled vehicles." I need to start contacting these vendors to find out why - is it a genuine incompatibility with computer controls, or are they just not certified for emissions? Still, you've about a half-dozen options from Crane, Crower, and a couple of other outfits, so we're not totally out of the running.
A lot of external engine mods that would normally be available to you will cause you to fail smog - not because they'd increase emissions, but because no-one's really bothered to get their add-ons certified by California for RENIX (1987-1990) XJ and MJ, and that's why the field suddenly opens up from 1991 (with the introduction of OBD-I.) Sucks, but that's what we're stuck with. And, why I do plan to leave California (and when I do, I plan to leave California to the Californians! I've had it with this place...)
Things you'll probably want to consider:
1) Re-gear. Especially if you have a manual. (If you have a manual, check to see if it's the Peugeot box of the Aisin. The Peugeot has a longwise split down the case, and should be replaced with the Aisin. I went through
four Peugeots in three years...)
2) You can bore the throttle body out, but the power gain would be minimal. The advantage would be in throttle response.
3) Consider adding a "cold air" intake - there's one certified for use on RENIX in CA, and it's made by XJ-Armor. Reports from the field on ordering from him are mixed... If you build a sheetmetal baffle around the thing and open up the hole that it breathes through behind the grille, you may see a slight increase in power (and a probable increase in throttle response as well.)
4) "Port-matching" will probably net you a minimal gain as well - but if you're willing to do the work, go for it! I'd suggest you get at least another intake before you do - so if you do screw up, you've got a spare...
5) Replace your fuel injectors. If you've still got the OEM ones (metal bottom/plastic top,) you're at risk of having them leak anyhow. Replace with Ford "blue tops" I think - you'll get better fuel atomisation, a little more power, maybe a few points added to your MPG, and the Smog Monkeys won't notice...
6) Re-gear. I know I said this earlier, but you're in CA - which limits your engine options. Therefore, you have to look at other solutions to your problem...