Car is in great shape, still gets 17 mpg in city on midgrade gas. Uses very little synthetic oil between changes. Plugs are not fouled. No blue smoke. Very small oil leak evidence at rear of driver's side head, not enough to drip but enough to see a dark spot. Tranny runs fine & shifts are smooth & great.

Getting somewhat close to 180K major interval: PO had timing chain, tensioner & guides all done @103K in 2000. Not hearing any real rattle at startup, runs very smooth and especially strong at upper end (as when flooring it occasionally at 35 or so and running it up to 100 mph). Maybe a very slight idle "tick" when really hot outside (for Portland, that would be a rare 90+ degree day) and car completely warmed up, a/c on, etc.

Not enough to bother me but just enough for me to notice.

QUESTION: should I just (A) have the timing chain guides, tensioner, etc. work done at the 180K interval or go all out and (B) have the all the top end work done, i.e. heads rebuilt?

What is a decent "ballpark" fair e$timate of the costs of (A) vs. (B)? On the one hand I don't want to service the chain and guides only to have to rebuild the heads a year later, nor do I believe it makes any sense to just "RUN IT UNTIL IT RATTLES" and then be faced with a blown engine &/or a bunch of broken parts that are not broken now.

I guess there is also option (C) which would be to wait until 200K or so...

Cheers!

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'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435