Do not run more than 33's with the BJ spacers, your tierods, draglink, pitman and idler arm will not like it. The idler arm especially, you can buy a total chaos brace and it will be needed.

Dont get me wrong, you can run 35's but the frontend wont like it to much, once you want to go over 33 its highly recommended imho swap to a solid front axle with hydrosteer if possible.

As for the 4.3, meh its ok I rather keep it toyota and do a 3.4L V6. With the correct gearing and installing perhaps a better cam like an RV cam from engbldr the 22RE can be a real decent powerhouse. Nothing like a larger V6 or V8 but the gearing and cam will allow it to work very well.