If it runs well and has done so for 250K you have a keeper!!! The replacement may bring its own problems. Consider if you wish, doing a compression or leak down test, and testing the oil through a lab. If all is good put a timing chain set in it and drive on!!!

Best of luck with whatever route you choose.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Why not a crate engine from GM?

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Jim

As long as it isn't showing symptoms of being worn out, I would just keep driving it.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

I just traded my 03 Dodge on an 08 which had 15,000 miles on it for the same reason.....me, the Mrs. and our dog out in the middle of bumfeck Idaho and the truck breaks. Not a good thought.

Last year when we lost the transmission in Yellowstone we were lucky enough to get the trailer to the campsite before the transmission became completely locked up. We're too old for such worries!

Peace of mind is worth a lot.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I'd be more worried about the transmission than the engine. If it isn't leaking, burning oil, or making strange noises, let it ride. GM truck engines seem to be very durable. If the tranny is original, it's been on borrowed time for a while. My BIL drove a '94 with the V6. Made it 286K on the original transmission before it died (and suddenly). Engine was still going strong.

They sold it for $700 and put that money towards buying his grandfather's '03 Dakota from his estate when he passed on. A move they've since regretted. Dakota is ALWAYS broken down, only has 65K, but is a SHOP. QUEEN. The old Silverado is still driving in town. The guy who bought it from them threw a used tranny in it and uses it as a farm truck. Still on the factory engine.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

If your engine is proven reliable but worn it makes sense to refresh it. Then you have a proven reliable engine with new parts.

I had a 400 small block in an old GMC truck. It was actually a very good truck engine. I would find an engine builder to make yours what it should have been from the factory.

Look for an aviation machine shop in your area.

Engine science has advanced in recent years. Someone who can talk to you about quench, static and dynamic compression, porting, timing, duration and lift, etc can make your time and money worthwhile.

But mostly, have fun with it.

If it ain't broke, don't fix it.

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2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

I came back to this thread to discover that it sounds as if there are no specific symptoms leading to the need for an overhaul. I would like to know more. Have you done a compression and/or a leakdown test? Does it have low oil pressure? Is it consuming a large volume of oil? Today's fuel injected engines of all makes are capable of many hundred thousand of miles when properly maintained and not driven abusively, especially if they primarily see freeway/highway use. If there is a symptom that warrants it, tear down, measurement/inspection and overhaul is the best way to go.

In this process you take care of the problem rather than paying for parts and machine work that are unnecessary. For example, if the crankshaft mic's out okay, tit isabsolutely not necessary to turn it. If the bores are only slightly worn, fresh rings are MUCH LESS expensive than boring to oversize and replacing Pistons. In fact you might be taking out much better Pistons than the Chinese junk you put back in.

One last thought. General Aviation, piston engine aircraft statistically have fewer catastrophic failures with very high time engines than the first few hundred hours after overhaul. The overhaul event just presents the possibility for things to go wrong. Aircraft engines have different specified Time Between Overhaul(TBO) reccomendation, depending on engine model. With Lycoming and Continental engines, there are many particular model engines that very commonly double TBO when properly monitored and maintained. Many variables play into engine life and it can vary widely.

Again, if it ain't broke, don't fix it.

Thanks, Larry. That is good advice all around.

But the problem may have fixed itself. Yesterday I had the windshield replaced since it had taken one rock too many. And the rust around the windshield 'frame' was extensive. I was told that without a rather high dollar body shop fix it was just a matter of time, like two years, before the windshield part of the body would not hold the glass.

The glass guy glued it in rather well, but he said it was not easy. And he did a lot of grinding work on the rust before he bonded in the windshield but he couldn't get it all. Otherwise there would be nothing to bond to.

So it looks like this is going to be a case of just drive it, and drive it in town, until something dies.

Because of the rust.

I have fought rust before in early Porsche's. I have always lost.

But I'm glad I started this thread. I can't be the last person to ask this question and now there is a lot of good advice for the next person faced with this.

There are some really smart people on this board.