Well here goes my first post of I'm sure will be many as I try to refresh my newly purchased 81 corvette. Well a couple weeks ago I purchased a 81 Vette, I know a little but by no means am I a gear head so this site has helped a lot. The guy I bought the car from didn't know much about it other than the engine had supposedly been rebuilt in 2007 by a prior owner but he had no paperwork or info on what exactly was done.
Little research has told me my engine has been swapped, block number 10243880. Comes up as a 95-00 block used on vortec trucks and the zz4 crate motor. My car has aluminum heads with angled plugs, an edelbrock proformer intake, and what looks like the original ecm controlled Qjet. Stock exhaust manifolds with true duals(no cats). Car runs well other then a slight rough idle I'm working on.
So heres my questions. How can I know if this is a real ZZ4? I can't see a ZZ4 stamp on the block near the fuel pump as some have said it should have. Where exactly should that be? It's extremely tight and I can't get a good look in that area of the block. Even tried using my phone to take pictures down in there, no luck.
Other question, regardless if it's a ZZ4 or a normal 880 block they added heads ect to, would my ECM work with either of these set ups? How do I even know if the ECM is working? (no check engine light at start up) i wanted to add long tube headers at some point, so should I just ditch the ECM or is it worth trying to make it work with headers? Thanks sorry, I know my post is a little long winded. Happy Fourth of July

 

It should have ''ZZ4'' stamped on the block in front of the right cylinder head:



The stock carb and computer should work fine with a stock ZZ4 crate engine. I'm planning on doing this swap in my '81 eventually

 

I bought a 85 Vette that was rumored to have a ZZ4. I found a bar code on the Head near the same spot as the picture above that had ZZ4 in it. If a Valve cover is easy to take off there is probably some sort of Part Number and a Casting date by who ever made them. You might even get lucky and see it threw one of the vent holes. A ZZ4 will have a bit of a Lump to it Idle but not to much, your Idle might just be the way its suposed to be.

 

there may be a sticker on the oil pan also

 

Thanks for the replies and i checked the oil pan. It HAD a slicker on the right side but what's left is completely unreadable. I'll have to check the area shown in the picture tomorrow, I wasn't really looking there. I thought it was further down. It's interesting what was mentioned about the idle if it is in fact a ZZ4. It was missing when I first bought it and would some times stall. Yesterday I changed the plugs, cables, dizzy cap and rotor and fixed a big vacuum leak in a headlight relay. The car seems to run better. Carb might still have to be cleaned and rebuilt, think the car was not being driven very much the last few years. It had a oil change sticker for 28500 miles dated 2008 and I bought the car with 25k miles and change a month ago Is the ZZ4 cam pretty mild? It does run a LITTLE lumpy but it's not very loud, but that might be due to the fact it has stock manifolds and some old Midas Golden Turbo mufflers (not a lot of info on these)

 

The ZZ4 cam is very mild. I wouldn't worry a whole lot about it being a "real" ZZ4, it's a good block but most of the other parts are none too exciting. At least you'll know what you're working with though.

The ZZ4 cam is a little more aggressive than the stock L81 cam, and a little less aggressive than the L-82 cam, although thanks to being a roller it makes a bit more lift.

 

Ok it's not a ZZ4 but after some cleaning I was able to make out V0223ZZ3 on the block in the same location as the picture above. Quick google search I guess this was a crate engine used before the ZZ4 came out? I got lucky and was able to get the numbers off the heads via the oil cap, those are 10088113. Anyone have any info on this engine?

 

Was able to find this on the internet:

High Output 350 (ZZ3)

PN: 10185072
Cost: about $3000 (includes many accessories, intake, distributer and water pump)
Displacement: 350 cubic inches (5.7L)
Horsepower: 345 at 5200 rpm
Torque: 387 lb-ft at 3250 rpm
Max RPM: 5800
Compression ratio: 9.8:1
Bore & Stroke: 4.00" x 3.48"
Pistons: Cast hypereutectic aluminum
Rods: 1053 forged steel "pink"
Heads: Cast aluminum, angled plugs, 58cc
Head specs: 1.94"/1.50"
Camshaft: Hydraulic roller tappet
Cam specs: 208/221 .474"/.510" 308/316 (advertised)
Idle: 750 rpm

Here's where I found it, if you're interested:

http://gbodyforum.com/viewtopic.php?...7#.UddRR77D-M8

Looks like the zz3 was the predecessor to the zz4, and they are pretty similar.

Scott