Hi all,

I am new to this forum. I picked up a 89 GTA back in May with 72k, but looks like the head gasket gave up and I need to pull the motor.

This is a gunmetal car with gray leather interior. Do I rebuild the original motor? Does that influence value with these cars?

The cost to rebuild is far more than the cost to get an assembled shortblock, reinstall rebuilt oem heads and reinstall the intake. I’d probably add headers and 3” exhaust and maybe some intake runners.

What do you guys recommend? And where can I get a good shortblock for reasonable
money? It looks like the ZZ4 has been replaced by the ZZ6. Is there a truck/suv shortblock I could opt for? I’m just looking for a mild driver; nothing crazy…

 

I think it depends on what you want. If it's a numbers matching/all original car then rebuild the current engine if it's possible. You didn't say what went wrong so it's a little tough to say. There are reman blocks both short and long that you can get pretty easily. The zz6 would be a blast but that's gonna take you down a different path!

 

All I can really say is that I was driving it (nothing crazy) and noticed white smoke billowing out the back. Wouldn’t start after shutting off.

I’m about 75% of the way towards getting the engine out of the car. Lots of coolant in the oil pan. Pretty sure this thing was driven hard thru its life; it has a full BMI suspension, so I can see the previous owner beating the **** out of it.

Anyway, here I am. I’d like to budget $5k for a long block essentially. I’d do the intake, install and startup. I don’t know it’s that’s realistic. I found a zz3 local for a decent price.

 

A zz3 will fit physically, the zz engines used heads w D shaped exhaust ports. If you have a L98 350 I think they're the same heads(?) if not, you may need to deal with the port not lining up to your existing exhaust. It will require tuning to get working w your TPI, there are people on here that know more about that. Make sure the zz3 is in good shape, it's got to be from the mid 90s. I had a zz4 in my car for years. It was a blast to drive.

 

Pull the engine, do an inspection, if there's no smoking gun, drop it off to machine shop to check for cracks or see if a rebuild is possible.
If it had never been apart, the intake gaskets are a common failure point.
I'd pull the plugs and see if you have water in cyl (s).

 

I'm actually eyeing a rebuilt ZZ4 at the moment. The ZZ3 shortblock I was looking at needs lifters, pushrods, rockers, surface rust cleaned off the deck, heads installed, etc. This ZZ4 will come as run-tested long-block for $1300 more than the shortblock. When it comes to the ZZ4, I'm assuming my existing intake will bolt up; that's based off what I've been reading on here.

When it comes to tuning, is that something I can address with a chip? Is that a thing with these cars? Somebody burn chips for these cars?

 

A ZZ3 or ZZ4 long block will work. The heads on the ZZ3 and ZZ4 are the Corvette L98 Aluminum and use the '86 and earlier intake bolt pattern. The center 4 intake bolts on your existing intake can be elongated to make it work. The other difference would be the EGR system. The F-bodies used an internal EGR system using the crossover passages in the cylinder heads and the Corvette/ZZ3/ZZ4 heads did not have this exhaust crossover and instead the intake manifold had provisions for an external EGR tube. If you are in a state that requires emissions testing and need to keep the EGR system intact, then you would also need the Corvette lower TPI intake manifold and external EGR tube. If you are not in a state that does testing or visual inspections, then there is the option to eliminate the EGR and program it out within the PROM chip. Just beware that even if a state no longer tests or inspects for emissions, it is still not legal to remove emissions equipment. Lots of people do it and never have any issue with it, but you will need to decide if that's something you want to do. Just giving options.

An L31 Vortec longblock is about as close as you can get for a stock replacement long block new from GM. You will need a TPI lower base from Scoggin Dickey that is designed to work with the Vortec heads (they are the only ones who currently make one and they were about $400 when I bought mine about 5 years ago). The EGR situation is the same as with the Corvette heads. Either do the external EGR pipe, or eliminate the EGR.

As was suggested already, I would get the current motor out and tear into it a little bit to see what you're working with. If it's the original 350 and never been rebuilt (measure the cylinder bores and crank journals), then it's probably a good candidate for a rebuild. You could drop it off at a machine shop and have it rebuilt to stock specs for likely less than the going rate for a new crate engine. No tuning needed with this option and everything you already have will bolt right up. All of the other options require some amount of other parts or modifications to make it work. Nothing too crazy, but just the nature of it.

I did the ZZ6 route with TPI. Yes, it was a cool project. But, the TPI system needed a bunch of aftermarket parts and/or a lot of massaging to get it to flow anywhere near what the ZZ6 needs. Really should have done a Miniram, and still may do that in the future, but I wanted to stick with TPI. It's also going to require tuning, which I haven't gotten into yet.

www.TunedPerformance.org does custom PROM chip tuning remotely.

 

Another rec for the ZZ engine. They're stout and a blast right out of the box.

If you don't rebuild the old engine and have the space to store it i'd recommend doing so. That's the kind of thing that, should you decide to sell in a decade or whatever, being able to offer the factory engine would matter to someone looking to do a restoration.

 

You guys have me convinced to spend the little extra $ and have the motor rebuilt. In terms of motor originality, is there a way to prove this is the original motor block? I've read different things on here regarding the block stampings. Do they include a portion of the VIN on the block or are we interpolating date of manufacture to determine originality?

For the rebuild, I'm thinkin of throwing in the ZZ4 equivalent cam and perhaps aftermarket heads to keep costs down on the rebuild

 

The original engine block would have been vin matched to the car. There is a machined surface on the block just in front of the passenger side cylinder head that will have stampings on it. It's been a while since I've looked at these, but I recall there being a 3 digit code that would tell you what the motor was and how it was configured and also a partial VIN, something like the last 4 or 5 digits of the VIN.

You may also find that it's not the original motor. A lot can happen in 72K miles. Tear it down. Figure out what it is and whether or not it's a candidate for a rebuild and go from there.

ZZ4 cam is TPI friendly. There are other options as well. Also many options for heads, but aftermarket heads and keeping the costs down don't really go together.

 

The reason I'm considering aftermarket heads is a can probably score a deal locally via marketplace on some rebuilt sbc heads. The question is what fits the TPI intake and exhaust for heads to have a little better performance over stock?

 

If you're looking for heads that will bolt right up, '87-'95 style small block chevy is what you want. Not the Corvette aluminum L98 heads, they use the older pre-'87 intake bolt pattern and do not have an exhaust crossover. Not that those items can't be overcome, but if you're looking for the most direct replacement, then stick to the standard '87-'95 style. There are lots of aftermarket options there, so it depends on what you find (port size, chamber size, valve size, cast iron or aluminum, etc). If you are going for a rebuilt stock head, then I would say just have your current heads rebuilt (assuming they are the original heads, need to check the casting numbers). There are 3 other cast iron OEM sbc heads from that era (not including the LT1/LT4) that will physically bolt up, but I wouldn't run any of them. Two are 305 heads and the other is the TBI 350 swirl port head . The OEM cast iron L98 heads would be the best choice if staying with an OEM head. Depends on what you want to do and budget.

If your existing motor and heads check out to be what came in the car, and they are in a rebuildable state, rebuilding that is a good way to go to stay within a reasonable budget. A rebuilt L98 with some mild porting in the heads, ZZ4 camshaft (with appropriate valvesprings & screw in rocker studs) and mildly ported TPI manifold will make for a fun package at a reasonable cost.

 

Thanks for all the info

 

You can use the corvette heads but will need to elongate the 4 center intake holes and drill tap the face of the pass head for an accessories mount

 

This is true, and elongating the bolt holes is pretty easy. The bigger hurdle is that the Vette heads also do not have an exhaust crossover, so the EGR will not work and will need to be programmed out with a custom PROM chip, or do the external EGR tube from the Corvette. In stock form, the Vette heads don't flow much better than the cast iron L98's, so not really worth the hassle. They can be ported to flow quite well, but I think the OP was looking for more of a direct bolt on solution.

 

Did you consider a ZZ short block with the factory heads ?
If I had to do something creative, I'd do a ZZ6 short block, with my small chamber 305 heads. The CR would be nice, and I'd really work the heads, and use the OEM TPI setup.

It's never gonna be an LS, so just have fun with the low end torque.

 

I was able to get the motor and tranny out of the car the other week and verify that it is indeed the matching motor. So havnt pulled it apart yet to see if I can identify the culprit, but looks like the original block is getting re-used, if sound.

 

Turns out it was the original/matching block so I broke the motor down and found the culprit. Looks like a bad head-gasket and water in the cylinder. I was able to find a reasonable motor builder in NH who rebuilt it and put the ZZ4 cam in it. I just got it back Monday. I'm going to have the transmission done as well since it came out with the motor. Now its getting exciting

 

Looks good! What valve covers are you going to use to fit over the rockers?

 

A bad head gasket is what took mine out as well.

Yes, looks good and should run well.

As TTop350 said, those rocker arms may not fit under the stock valve covers. Do a test fit, but might need a taller cover.

 

I was wondering that as well. I was going to try and grab a pair of the magnesium C4 covers bc I like the look but any recommendations? I really don't like the stamped steel look

 

The valvecover webbing and air oil separator wont fit with those rockers without mods.
the vette covers will need some milling for clearance,
the stamped steel will need some webbing cut out.
a narrow body rocker would make it easy.
ive used the comp rocker like those and had to modify my covers big time.

 

The pro form/zz6 covers work well on my heads w roller rockers.

 

Thanks for the recommendation. I'll check those out. I might mill the Chevrolet off

 

Great to hear your motor was saved. Looks like your re builder did a great job. I'd be excited too!

 

yeah, I'm not a fan and thought about doing the same.