Hi,

My antifreze is probably going into the cylinders because I can't see any leak and I lose some 1 quart in 20 miles...
The oil looks clean. Is it ok to keep driving the car like that for a while?

Once I get to the head gaskets, can I make any performance upgrade? My engine is a stock 350 tpi from '89 with 110k miles on it. I don't want to spend a fortune, not more than 1k in parts.
I was thinking to put in 1.6 ratio rockers. Do I need stiffer valve springs too?
Do I need headers too?

What other repairs/upgrades can I do since I'm there? I may want to change the cam chain too if it's easy to get to.

Thx for any input!

 

Keep it modest. Serious upgrades are probably not worth doing unless you are going to yank and completely rebuild the motor. Read: don't mess with the cam or timing chain- that's more work than you want to tackle on top of a head gasket repair. If you're going to do that it would take less time to yank the whole motor and work on it on a stand.

I would do valvesprings for sure. The heads are coming off so there's no better time to upgrade. My "hot tip" for upgrading valve springs on stock heads when using a stock cam is a set of Comp "981" springs. They will literally drop in place of the stock units without any modification whatsoever. They are a fair bit stiffer than stock and work well with both flat tappet and factory roller cams. You've never known how good a TPI motor can really rev until you've put some decent springs in it.

1.6 rockers are also a sensible upgrade with a stock cam, but DON'T BOTHER untill you're going to do the valve spring upgrade as well. Higher ratio rockers work the springs harder and the stock ones were barely adequate for a stock cam, even when new. Be sure you get the right rockers (self-aligning, for 88-up motors, unless you want to convert your heads to screw-in studs with guideplates and use earlier non-self aligning rockers). Also be aware that typical, fat aluminum roller rockers are often a bit too wide to fit under a stock centerbolt style valve cover. I've done it with Harland Sharps with some minor tweaking of the baffle box, but if you want something that is truly bolt-in you're looking at some very expensive Crane Gold narrow body rockers. That may be more than you're into sprending or modifying for a rocker arm upgrade right now. A possible alternative is a set of stock-style stamped steel self-aligning rockers but in a higher 1.6 ratio. I BELIEVE somebody makes them but I can't seem to recall who right now. IF they exist, the cost would probably be reasonable and installation would be as simple as stock.

You could also take the opportunity to have your heads pocket-ported a little, have a nice 3-angle valve job done. I only mention it since the stock valve job could probably use some freshening-up anyway after 110K miles........ and if you've got the valves out why not have the ports cleaned up a little? You could do it all at once along with the valve springs.

Headers always help. A set of Hooker shorties and y-pipe will always do better than stock manifolds and pipes- even if you're still running the stock cat and muffler. Remember a muffler shop is going to have to attach the supplied y-pipe to your cat, so factor in a few extra bucks for that.

While you've got the TPI apart you might want to put in an adjustable fuel pressure regulator and have your stock injectors cleaned and tested. Again, no better time to do it than while it's already apart.

 

wow, thx for the reply!

I replaced recently the Y pipe so I was wondering if I can use shorty headers with my pipe?

those head gaskets come in different compresed thicknesses, what do I need and what brand?
thx a lot!

PS: I'll get a porting kit and get busy over the winter-hehe-

 

A stock y-pipe that works with your factory cast iron exhaust manifolds won't work with headers. Fortunately, the Hooker shorties come with their own Y-pipe. They come in both emissions-legal versions (with air tubes for the smog pump and O2 sensor) and non-emissions version (I beleive these still have an O2 fitting which you definitely will need, emissions compliance or not). And you can choose between ceramic coated (highly recommend) and non-ceramic coated (which will be rusty everywhere in a week, but they're still functional).

Besides, the stock y-pipe ain't so good. The junction where the pass. exhaust manifold down-pipe hits the main pipe is a disaster- more like a "T" than a "Y". You wouldn't want to use it anyway.

Head gaskets choice: GM Performance Parts .028" compressed thickness composite head gasket. Available from Scoggin Dickey and elsewhere for about $35 a set, and yes, they work just great- I have a set on my supercharged 383 in the Malibu. Here's a link:

0.028" - Composition Small Block Chevy Head Gasket :: 10105117 - SDPC

You don't want to use anything thicker (like a typical Fel Pro .039") or you'll lose compression. There is no thinner composite head gasket. You don't want to use a thin steel shim type gasket becuase they can be difficult to seal up on used parts.

 

thx a million!

u're a lifesaver.