I have an 87 Camaro that has the H.O. conversion installed. Part number 10185077 with the ZZ4 motor. I did not get the "Decal, Under hood Tune Up Label P/N 24502462 with the kit or I may have simply overlooked it and threw it away with all the packing that the kit came in. I need to do a tune up and I need the information on this label. Can you help with timing and plug gap information? Or give me a part number for a suitable subsitute label?

 

Are you sure you have the zz4 motor? That part number is for the 350HO crate engine conversion...

Anyway, if you have the 350HO crate engine, I ran the NGK TR4 spark plugs at I think .035 gap. As for timing, it depends on what the engine likes and what kind of fuel you are running. I would set it around 10-12* base timing and as much as 36* total timing.

 

The was no 350 HO conversion. The HO 350 Camaro Conversion was based around a ZZ4 engine. It kept the CC carb and ignition set-up.

I don't know the p/n for the decal (don't have the parts list with me right now, not even sure it's on there), but 12 degrees base timing is going to be way too much. Start at 6 degrees BTDC and work from there.

 

Oops you are correct, I always assumed that was the 350HO motor since it only makes 308 horsepower with that induction/exhaust setup.

As for the timing, I ran 36* initial when my motor went 12.8's, I dont think 12* base timing would be too much depending on what his total timing ends up being.

 

This H.O. conversion is suppose to pass emission testing and has done so for the past 5 to 6 years since the conversion was installed. It's not passing now and thats why I'm looking for the tune up info. I have the manual that lists all the part numbers along with installation instructions. This is a ZZ4 motor according to the number on the block, the manual has it listed as a ZZ3. The emissions lable is no longer available through GM with no replacements or even a suggestion. I have tried setting the timing at 10 degrees initial timing and loose top end power but it has a good idle. Setting the timing below 4 degrees gives great mid and top end power but it will not idle. I have no idea which way to get the best emissions readings.

 

I got the following off the GM Performance Parts catalog for a ZZ4 engine:

Spark Plugs ..................... FR5LS Gap .035
Rapid Fire #5 Gap .045
Fuel ............................. 92 Octane
Ignition Timing .................. 10o BTDC @ 800 RPM
32o total @ 4000 RPM with vacuum
advance disconnected


I hope it helps.