I'm trying to be a realist about my motor, but every gearhead I know says totally different things. I've heard everything from "your engine will throw a rod any day now" to "for a 305, thats barely broken in." Here's what I know about it:

166,000 miles, mostly highway, driven mostly by the same person from 16 y.o. to 22 y.o. This is the TBI version of the 305, and I've never seen it shift later than 3,000rpms or so. I'd assume this motor has never seen revs much higher than that in its life.

The good: it idles smooth and quiet somewhere around 500-600rpms, the rpm's don't jump around and as I work on tuning it up, the throttle is increasingly responsive by leaps and bounds.

The bad: burns oil for 4-5 seconds on a cold start, small oil leak (shouldn't need topped off much, if at all between oil changes).

What should I reasonably expect from this thing? 20,000 miles? 2,000 miles? The body could really use some help, and I hope the motor will last long enough to do rust/damage repair and paint first, as I can't afford to do both at once.

 

I have the same problem!! I was recently told that a heavier grade oil along with the lucas oil additive would decrease oil seeping through the lifters, rings etc...

 

I say run it stock til its gone. Sounds like your valve guide seals are bad, it's a pretty common thing for stock seals to go bad. You could leave it like that for a while, It's not really going to harm anything. I drove with bad seals for a while, it was more embarassing than anything. While you keep driving it stock, you can save up some money for a fresh motor, perhaps a 350, perform some mild mods or just keep it stock, and swap it when you're ready. A motor with 160000 miles isn't really a good place to start as far as mods, especially a tbi 305. But it'll get you around town. It should last you a while, cant really say exactly how long but 305s are capable of 200000 miles when taken care of. And it sounds like your nice to it. Good luck with the car!

 

I'd say 90% of the time the blue smoke on startup is nothing more than valve seals. It's fairly cheap and not too complicated. As long as it doesn't smoke otherwise give it a shot.

Based on your description, it doesn't sound like that engine is going to grenade on you anytime soon.

 

I agree with you about the mods. I'm really only working on tune up things (plugs, wires, better oil. etc) and then free mods (removing smog pump, A/C, easy air intake mods, etc). I know this motor will never be anything really special, I just need it to get along a few more years as a part time driver (my daily driver is an 04 mitsu that gets good mileage but has no soul). Then after the body is shaped up, maybe drop in a nice 350 or 383 stroker

So 200,000 miles would be really nice. How many miles have others gotten out of their 305's?

 

I've been driving this thing a lot since I got it two days ago. Knowing it had been in storage for a few years, I wanted to get it going again as quickly as possible. The motor has been acting better and better, but for the first time this afternoon, it really responded when I jumped on the throttled as it downshifted and pushed me back in the seat a bit. I'm being really encouraged by this engine's progress, so hopefully you guys are right and it'll last me a while

 

Its a small block chevy, itll just keep going and going and going, even if its rough.

 

I'm running a 305 TBI as well. No oil burning at all, but I have developed an oil leak most likely from a minor crack somewhere in the oil pan (the last shop I was at mentioned something). I occasionally drive it hard out on the highway and has not even come close to running anything other than prime.

 

Lmao its so true about sbc. My mom has a 91 gta with 220,000 miles on it. It has the worlds smallest valve guide leak. Only on start up. Nothing else is wrong with the car and nothing has been touched other than injectors.

My 88 iroc's motor has been hit with spray more than life. I finally pulled it because of the new build. I checked the cylinder walls, and they were as smooth as when it was brand new. Think about that. 20 years ago my car was made. MAkes me happy

 

I bought my 88 T/A with a L03/700r4 rebuilt with only 9,000 miles on motor, 11,000 on tranny. But like everyone else i have smoke on startup, which means valve seals are bad.... Runs great and shifts awsome and can hit 4,500 rpms with no problem and still squak the tires into 2nd. Body has like 121,850 and could use some paint/bodywork. T Tops leak but yet again whos dont??? Still runs great and have alot of mods done and have more to come. Then once this engine takes a **** on me, ill swap for a 383 in my barn and swap mods.

 

The 305 TBI out of my car still ran at 227k miles when i pulled it. After a set of new valve seals, different intake, and a holley 650, it is now powering a 3/4 chevy 4x4 that belongs to a friend of mine. Slightly modded, but the bottem end was stock. It got 13.6 in the quarter when i had it in my car.

A lot of mods for a 305 can be carried over to the 350, like exhaust and gears. And it gives you plent of time to build an engine to swap in later.

I would change the valve seals, and run it like that. If you want dependability, I would guess another 100k miles if you take good care of it.

 

166k is nothing for a SBC, especially one that doesn't really have the power to hurt itself like the TBI 5.0L... there are lots out there with twice that mileage that still run just fine. Friend of mine has a truck with the 5.0 TBI with something like 480,000 kms on it (~320k miles) and it still runs just fine. Typical valve seal leak causing blue smoke on cold starts, but otherwise just fine. I wouldn't worry about it at only 166k.

 

Take good care of the engine and don't abuse it. It is not a uncommon at all for valve guide seals to start leaking. Such is the price of age and heat. Leaking valve guide seals are not that bad of a thing, other than the fact that it looks weird and smells bad when you first start the car. On the plus side it keeps your cylinder walls coated with oil on cold startups. Take good care of it and you will have no problems getting 200k out of it. Also some of the high mile motor oils, like the high mile mobil 1 synthetic 10W30 will help diminish the cold start oil burning.