Hi,
One of my friend has a GM 10243880 stamped crate engine. He's building up a Corvette from scratch with it.
Other stamps are 5.7LG SGI and 880 H31 on the rear (time code probably)
I don't think this one was made in Mexico

Here are some pictures.




The $1M dollar question is : what flywheel (153 or 168 tooth count) is matching this engine

I thought the way starter's bolts holes were aligned would give a clue but the block offers 2 kinds (aligned and staggered) so there are 3 holes and this can't be conclusive.

Any idea to help me to determine the flywheel tooth count ?
Thank you.

 

Both work, the starter will need to match what you are chosen (staggered or inline) but either way you should be golden. You may need an external fuel pump since they were hit & miss on the drilling. Probably a vortec motor. They came in a lot of configurations. Most were used in trucks. Funner motors were the ZZ4 and RamJet 350's

Additional parts that may be needed: Flywheel / Flexplate: Like all small block V-8 engines produced since 1986, the ZZ4 engine has a 3.00” diameter flywheel flange bolt pattern. Small block V-8 engines produced from 1958 through 1985 had a 3.58” diameter flywheel flange bolt pattern. This change in bolt circle diameter was made to accommodate a leak-resistant one-piece rear main seal. Due to revisions in the crankshaft design, a ZZ4 engine must have a counterweighted flywheel (or flexplate) for proper balance. The ZZ4 engine includes a flexplate Part number 14088765. Additional flywheels and flexplates are available from the chart below. ZZ4 Engine - Manual Transmission Flywheels Part # Outside Dia. Clutch Dia. Starter Ring Gear Teeth Notes 14088648 14” 11.0,11.58” 168 For one-piece crank seal 14088646 12 3/4” 10.4,11.0” 153 Lightweight nodular iron flywheel, weighs approximately 15 lbs.; for one-piece crank seal 14088650 12 3/4” 10.4” 153 Standard weight flywheel; for onepiece crank seal ZZ4 Engine - Automatic Transmission Flexplates Part # Outside Dia. Conv Bolt Pat. Starter Ring Gear Teeth Notes 14088765 12 3/4” 10.75” 153 For one-piece crank seal 12554824 14” 11.50” 168 Heavy-duty flexplate with increased thickness for one-piece crank seal 14088761 14” 10.75,11.50” 168 For one-piece crank seal

 

96-02 vortec. 1 piece seal. 168 tooth flywheel but you can not use your old one. no mechanical fuel pump option. 4 bolt. roller lifter. give chebby engineers a 265 v8 block and 40 years and this is what they designed. i bought one for a head. can not justify letting the block go. thick shiny black paint. rust where there is no paint. mercruiser engine...

 

Thank you guys !

This is very detailed information

So as my english is not that good, am I correct on the following :

- GM Vortec
- Date : Feb 96
- Rear seal : 1piece (we can see the rear seal on the back of the block in the rusty picture if I'm not mistaking)
- 4 Bolts
- External/electrical fuel pump only
- Probably a Mercruiser Boat motor originally.

I can install 168 tooth count flywheel from the moment my starter (staggered bolts = not straigh/taligned) AND my cluch (+bellhousing) is 11" - Correct ?

Thank you for your kind confirmation
Have a great day.

 

Mercruiser 5.7l Alpha 1 Thunderbolt 250/260 horsepower.
How do I know? See the blue circle? That is the low pressure cutoff switch for the fuel pump and this is 100% Mercruiser setup.
The thick black paint is a tell too as mentioned above......





Jebby

 

you think corvette tax is bad? wait til you pay boat tax. that is nice shiny paint. it friggin well better be. it makes EVERYTHING cost 3 times as much!

 

Although I agree that it looks close to a Mercruiser, I'm not so sure. Mine had brass freeze plugs and yours appear to be steel from the pictures. Could just be the way the picture is.

Either way I actually had a Mercruiser crate in my C3. It worked just fine. The cam is setup for wide open throttle most of the time so it is fairly hardened. They have some changes in hardware due to the saltwater aspects but overall they start with the same exact block as the truck motors before they tweak on it a little bit.