My 1990 4runner 22re w/ 170k is super clean and very sound mechanically. Gets 21mpg around town and some off-road use. Uses no oil between changes. However, it still has the original timing chain and clutch. The clutch seems fine and will decide later when I want to deal with that. The mechanic I had look the truck over felt that the only oil leak I have is the half moon on the rear of the valve cover gasket area. I thought it might be a rear main seal but we'll see after the valve adjust and gasket replacement that will be done when the timing chain is replaced. If that cures the oil leak, I'll let the clutch go for now. If it is a rear main oil seal, I'll have the clutch done at the same time as the rear oil seal.
After research on these pages and others, I've ordered a dual row timing chain kit from LC Engineering and will have it installed Monday. It comes with new sprockets, chain, timing chain cover, oil pump, water pump and metal guides. Probably overkill and costs a bit but was told it should last 200k plus. My old timing chain was starting to make some noise. The Toyota shop I went to said he didn't think the chain was loose enough to be hitting the cover yet but sounded like the plastic guide(s) we're coming loose and probably didn't have much plastic breaking yet. He was a Toyota dealership mechanic for years before opening his own shop, has plenty of certification certificates on his wall and seems to know his stuff.

Has anyone used one of these dual row chain kits?
Did it reduce fuel economy?
Any other info. from your own experience with this upgrade?
If I do the clutch, he recommends a standard replacement clutch rather than a centerforce because of how I use the truck, original lasted 170k and still going. Input on this would also be appreciated.
Thanks fellow yotaheads.