[80camaroguy]

i have a zz4 block and vortec heads it all a stock motor came out of a truck i am wonderin g what i have on the insidew of this motor i ran the numbers like i said but if you would like the numbers i can put them on the post and maybe if you can tell me round about hp any help appreciated

[oldbogie]

Originally Posted by 80camaroguy

i have a zz4 block and vortec heads it all a stock motor came out of a truck i am wonderin g what i have on the insidew of this motor i ran the numbers like i said but if you would like the numbers i can put them on the post and maybe if you can tell me round about hp any help appreciated

The ZZ4 is not a production engine, if it's in your truck somebody put it there. If it's really a ZZ4 here's the GMPP specs.

Horsepower .................... 355 @ 5250 RPM
Torque .......................... 405 @ 3500 RPM
Max. Recommended RPM .... 5800
Compression Ratio ............. 10:1
Block ............................ 10105123 Four bolt main, cast iron
Crankshaft ...................... 12556307 Forged steel
Connecting Rods ............... 10108688 PM rods
Pistons .......................... 10159436 High silicon aluminum with offset pins
Piston Rings .................... 12528817
Camshaft ....................... 10185071 Hydraulic roller Lift .474" I, .510" E. Duration @ .050: .208 o I, .221 o E.
Intake Manifold ................. 10185063 Aluminum dual plane
Distributor ...................... 1104067 HEI
Cylinder Heads ................. 12556463 Aluminum 58cc combustion chambers
Intake Valves ................... 10168465 1.94"
Exhaust Valves ................. 10168514 1.50"
Valve Springs ................... 12551483 LT4 chrome silicon
Rocker Arms .................... 10089648 1.5 ratio
Valve Lash ...................... Zero
Spark Plugs ..................... FR5LS Gap .035 Rapid Fire #5 Gap .045
Fuel ............................. 92 Octane

It would originally had L98 aluminum heads that were used on the 1985 thru 1992 Corvette, not Vortec heads. Don't let the little chamers of the L98 head fool you, they put a really thick gasket under them so the compression is no-where near what one would imagine with a 58 cc chamber.

This begs the question how do you know it's a ZZ4?

Bogie

[80camaroguy]

well i dont think its a zz4 expecially after you post but it block number matches that of a zz4 so i didnt exactly know what i was dealing with so does this mean its a regular vortec and if so what size cam and such is in it
or how can i tell

[oldbogie]

Originally Posted by 80camaroguy

well i dont think its a zz4 expecially after you post but it block number matches that of a zz4 so i didnt exactly know what i was dealing with so does this mean its a regular vortec and if so what size cam and such is in it
or how can i tell

The 10105123 is a heavy duty one piece rear seal, 4 bolt main, roller cam block. A darn good choice for a build. The Vortec heads might tell you this is one of the heavy duty L31 Vortec's. As a crate motor they are GMPP part number 12530283. The L31 crate motors come in two flavors, the heavy duty with 4 bolt mains and the regular duty 2 bolt main part number 12530282.

The cam for either of these uses 191 intake and 196 exhaust degrees measured from .050 inch lift. The lift at the valve is .414 intake and .428 exhaust. That's easy to measure compared to the lift at the valve on the ZZ4 of .474 and .510 inch in. and ex.

The Vortec L31 iron head out of the box makes about 15-20 more horses than the L98 aluminum head. The difference is in subtle chamber shape changes and better placed intake ports.

I'm outa here for the night.

Bogie

[80camaroguy]

thank you i feel as if that was very helpful