I have a 91' 3.0 4 runner with a newly rebuilt engine installed myself. I've opened up the bottom of the intake box to give'r more air, now I'm on to the exaust... I have been given a FLOWMASTER muffler but it's for a Chev truck (3" intake with dual 2 1/2" outlet) wondering if this is going to be too big for the engine, and my have no back pressure?? ( will be installing after the cat converter.) but it will give a nice sound I hope and the look of Duals. Second part looking for suggestions on wher to run the tail pipes out?? #1 (angled to sides behind the rear wheels each side) or #2 (straightout the back about 6" in fro either side of the truck) also thinking of chrome tips for tailpipe the ones about 1' long with the tappered cut. any photo's or suggestions would be Great. beiggest concern is the size of the pipes in the muffler and the effect it may have on Preformance...

 

Is this a 4WD? I wouldn't go straight out the back with chrome tips. I would rip those off the first trail I hit. Think departure angle and stay clear in the rear.

I would stay as close to this write-up as possible, it seemed to work good for him.
http://www.4x4wire.com/toyota/tech/downeyheaders/

At the very end of the instructions Scott said:

"I have now had two different exhaust setups with these headers. Based upon my experience I suggest running 2-2.25" pipe off of the headers, and when the two pipes combine to one, then bump up to 2.5" pipe the rest of the way out. This is the largest size exhaust I would recommend running. If you put too large of an exhaust pipe on your engine, it will not have the back pressure it needs, and you will actually LOOSE horse power and torque from your engine."

 

3" is wayyyyy too big.

 

Yeah it's a 4x4 thankx for the info I wuz hoping i could use this muffler cuz it was free..... but I really don't want to lose and torque or power will keep looking thankx

 

Yah, free is always good, but it's not worth the loss. Seems like the general consensus is the 2.25" is best for most 3.0's, and 2.5" is the biggest you'd want to go.