Hi all,

I am based in Melbourne, Australia and was running an 89 Coupe and have unfortunately thrown a rod through the block on a recent track day.

The original engine config was:
6 speed manual
Camaro single mass flywheel
383 stroker with 10.8 to 1 compression
1991 L-98 block, machined for splayed main caps
Eagle 4340 3.75" stroke crank
Clevite 77H series racing bearings
Manley 4340 6.0" H-beam rods
Forged SRP dished pistons with Teflon coating
SpeedPro file fit rings
Cloyes double roller timing chain
Melling high volume oil pump
OEM oil pan
Lingenfelter 72219 camshaft
New OEM roller lifters
AFR 190cc heads with 7/16" rocker studs, angle milled
Crower Hi-Tech stainless steel roller rocker arms, 1.6 ratio
Edelbrock lower intake, ported
LPE Superram upper intake, ported runners
Edelbrock 58mm throttle body
Fluidamper balancer
Rotating assembly was internally balanced
Hooker 2149 coated long tube headers
Computer swap to speed density computer (730 ECM)
Ed Wright computer chip


I am looking to replace it with an engine that Eagle Spares here sell - a ZZ383 425Hp GM crate motor - http://www.eagleautoparts.com.au/12498772.htm

Details are:
Part No. 12498772
With GM's legendary Fast Burn cylinder heads and 383 cubic inches, the ZZ383/425 delivers incredible torque with smooth, linear delivery.
If your're looking for a small-block package that delivers big-block power, then you've found it.
425 horsepower at in incredibly low 5400 RPM, and 460 ft.lbs of torque at 4500 RPM make this the ideal hot street engine.
The excellent air handling and combustion characteristics of the Fast Burn cylinder heads combined with the ZZ383/425's 3.800" stroke, make this engine the benchmark against which all other 383 inch small-blocks should be measured. And its tough, too.
The 4340 nitrided and induction hardened crank and unique forged PM rods see to that.
The 9.1 to 1 compression ratio ensures that the ZZ383/425 is 92 octane pump gas friendly.
The ZZ383/425 gets a stout .509/.528 lift steel camshaft with 222/230 duration at .050 lift. Hydraulic roller lifters and GM's time tested 1.5 to 1 roller rocker arms round ou the valve train.
And, of course, it has the Fast Burn head's lightweight stainless steel valves and retainers for reliable performance at extended RPM.
GM's testing was completed using a GM single plane intake, P/N 12496822 and a 750 CFM Demon carburetor with mechanical secondaries.
Test header specs are: 1 3/4" primairies,33 inches long with a 4-inch collectors.
GM dual plane intake P/N 12366573 may be used for hood clearance on the ZZ383/425, but it results in a decrease in peak horsepower of approximately 15-20 horsepower.


My concern is will this swap and can I keep my heads and/or intake manifold etc? I am not sure if the porting is different or any other issues I am likely to face.

Any assistance would be GREATLY appreciated to get me back on the track for another event in 2 months.

Thanks in advance,
Darren.

 

Call Eagle and ask if the intake bolts that are 90 deg to the ground as opposed to the 45 degrees we have seen since '55. Most small blocks use the 45 yet. This describes the difference between the type I and II head/intake bolt pattern. The intake holes can be drilled and tapped to match the degree of the heads. Check with a good high performance machine shop in your area. You may have to do the redrilling for the tuned port...you have to drill out the manifold until there is almost no material left on the outside edge.

If you want to keep the "old heads and intake" they should just bolt right up but the results in a decrease in peak horsepower over all approximate horsepower drop will occur due to miss matched flow characteristics of your "old and new" parts (cam, heads and intake restrictions). If you swap the heads/intake over you may want to swap the old cam too.

Cloyes double roller timing chain/cover may also cause a problem with water pump clearances....or maybe not.

Again --call Eagle and tell them what your trying to do. If they're stand-up people they will lead you down the right path....to the correct answers or to someone who knows the correct answers.

 

Thanks engle1147, appreciate the assistance....