ZZ4 upgrades? - Chevelle Tech
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post #1 of 89 (permalink) Old Sep 5th, 19, 10:12 PM Thread Starter
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ZZ4 upgrades?

Where are all the ZZ4 guys at? Im looking to upgrade possibly. From the stamping on my ZZ4, it appears to be aluminum l98 heads stock everything. Center bolt valve covers. Feels like a turd to me power wise and looking to upgrade with bolt ons.

If it's not broken, let's fix it till it is.
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post #2 of 89 (permalink) Old Sep 5th, 19, 10:28 PM
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re: ZZ4 upgrades?

Quote:
Originally Posted by Hotrodder000 View Post
Where are all the ZZ4 guys at? Im looking to upgrade possibly. From the stamping on my ZZ4, it appears to be aluminum l98 heads stock everything. Center bolt valve covers. Feels like a turd to me power wise and looking to upgrade with bolt ons.
Have you spent much time dialing it in? I know someone that had a stock, except for headers, ZZ4 in his 65 El Camino, he ran it with a 700R4 and a mid-3 series gear. It always ran 12.70ís-12.80ís. Iíve also seen guys at the track that couldnít get ZZ4 equipped cars to run quicker than low-14ís, but thatís more about their lack of tuning and driving skills than the engine itself.

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post #3 of 89 (permalink) Old Sep 5th, 19, 11:08 PM
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re: ZZ4 upgrades?

The distributor curve sucks. Mine was kinda lame out of the crate, but now I'm running a recurved (ZZ4) HEI, HOTcam, RPM intake, long tube headers, and a 650 holley DP and it pulls hard. Never had it to the track when it was in my Chevelle, but now that it's in my 4000# truck,(89 reg. cab short bed 4x4) it surprises a lot of "fast cars" on the road. It really liked a 750 DP, but mileage really suffered. I'm going to try a 750 AFB next. The HOTcam helped it pull harder in the upper RPM range and didn't give anything up down low. Slight lope, and great vacuum. There are a lot of better cams out there, same with heads, but I say work with what you got and start with recurving the distributor. There's quite a few discussions online about it.
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post #4 of 89 (permalink) Old Sep 6th, 19, 12:15 AM Thread Starter
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re: ZZ4 upgrades?

Im working on figuring out how to get it tuned properly in another discussion. It really feels like a dog right now but every once in awhile it wakes up for a pull. This morning I was leaving walmarts parking lot and I jumped on it for the hell of it. Ass end swung out a bit. I didnt know where the hell it came from because ive have nothing but issues with it cutting out while accelerating. Maybe its just way off. Transmission is a TH400 Auto 3 speed with 2800 stall. 3.73 gears. As of right now, I cant even get the tires to spin.

ZZ69chevelle. I see your from the Reading area. I moved out of Mt. Penn in 2016 and came down to Delaware. Grew up in Pottstown/Boyertown.

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post #5 of 89 (permalink) Old Sep 6th, 19, 12:30 AM
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re: ZZ4 upgrades?

I moved to the Blandon area from Douglassville, so you were pretty close. Wife still works in Boyertown. Where do you have your dist. vacuum advance plugged in? Timed or manifold vacuum? I run mine from a manifold port. Even after recurving my distributor, it used to hesitate with the timed spark vacuum port.
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post #6 of 89 (permalink) Old Sep 6th, 19, 6:50 AM
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re: ZZ4 upgrades?

what is your initial timing?

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post #7 of 89 (permalink) Old Sep 6th, 19, 9:52 AM
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re: ZZ4 upgrades?

I have a ZZ4, been in it since 1997, stock everything, right about 30K miles on it. Still have the 1967 iron exhaust manifolds. Stock 700R4 that drives beautifully but under WOT, hangs 2nd too long and you have to lift a bit to shift.
I put FiTech GoEFI 600 on it for kicks, runs better, but basically the same as the 600 AFB that was on it. As others said, timing is probably the key, I KNOW mine isn't optimal, I have played with it a bit with vacuum, without (as suggested by the paper that came with the engine) vacuum to ported, to unportedÖ But admittedly, I haven't tried hard. And I probably won't, I will just setup the EFI to do it all without messing with locks/springs/weights.
BUT with what I have, and some stuff in the El Camino, it runs high 14s while being super at daily driving. I have a posi, and what I assume is a 3.0x or 3.2x rear. It does pull like it could do better, maybe 14 flat, but I never wind it out that much over 5K. It has 215/70-14 plain jane tires and actually launches okish. Every time I want to make it run better, I get a daily driver that blows it away, and I figure why bother. I'm concerned that if I up the ante on power, that is when I will start to break things like the transmission (we paid $500 for it in 1997) or the 52 year old rear axle, stuff like that.

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post #8 of 89 (permalink) Old Sep 6th, 19, 10:32 AM Thread Starter
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re: ZZ4 upgrades?

Quote:
Originally Posted by ZZ69chevelle View Post
I moved to the Blandon area from Douglassville, so you were pretty close. Wife still works in Boyertown. Where do you have your dist. vacuum advance plugged in? Timed or manifold vacuum? I run mine from a manifold port. Even after recurving my distributor, it used to hesitate with the timed spark vacuum port.
Quote:
Originally Posted by Tom Mobley View Post
what is your initial timing?
To be honest with you, I dont even know what your talking about when it comes to vaccum. I understand the concept but have never worked with it before. Ive never even set timing on a motor. Im going to attempt the timing today once I find a gun.

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post #9 of 89 (permalink) Old Sep 6th, 19, 3:50 PM
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re: ZZ4 upgrades?

Here's a good read on it.
https://www.chevellestuff.net/tech/a...r_manifold.htm
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post #10 of 89 (permalink) Old Sep 6th, 19, 5:04 PM
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re: ZZ4 upgrades?

This is the part that everyone questions
"Set spark timing at 32ļ before top dead center (BTDC) at 4000 RPM with the vacuum advance line to the distributor disconnected and plugged. This setting will produce 32ļ of total advance at wide open throttle (WOT). The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal centrifugal advance to achieve the correct timing curve"

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post #11 of 89 (permalink) Old Sep 6th, 19, 5:18 PM
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re: ZZ4 upgrades?

Quote:
Originally Posted by Pioneer4x4 View Post
This is the part that everyone questions
"Set spark timing at 32ļ before top dead center (BTDC) at 4000 RPM with the vacuum advance line to the distributor disconnected and plugged. This setting will produce 32ļ of total advance at wide open throttle (WOT). The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal centrifugal advance to achieve the correct timing curve"
That doesn't mean to leave the vacuum advance disconnected permanently.

It means to verify what your total advance is (centrifugal + initial) , you don't want vacuum entering the equation because it doesn't operate at wide-open throttle.

Always connect the vacuum advance to full manifold vacuum - if you want the engine to run cool and get good mileage - and be easy to start.

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post #12 of 89 (permalink) Old Sep 6th, 19, 7:20 PM
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re: ZZ4 upgrades?

Here is what I did with my ZZ4 engine years ago, took the cam out and dropped in a LT4 hot cam. Was like night and day performance, not real lopey and the car had great driveability.
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post #13 of 89 (permalink) Old Sep 6th, 19, 9:03 PM Thread Starter
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re: ZZ4 upgrades?

Quote:
Originally Posted by 68Chevele View Post
Here is what I did with my ZZ4 engine years ago, took the cam out and dropped in a LT4 hot cam. Was like night and day performance, not real lopey and the car had great driveability.
You didnt change anything else? Literally just swapped cams?

If it's not broken, let's fix it till it is.
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post #14 of 89 (permalink) Old Sep 6th, 19, 9:12 PM
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re: ZZ4 upgrades?

The Hot Cam and Springs are a great upgrade....but you're not ready for that YET.

Instead, find a local dyno shop that still works on carbs and have your carb AND ignition tuned.

You have a real 350 HP V8 and 3.73 rears gears. You should be shredding tires at will off the line. Either your motor has a fatal injury....or your tune just sucks. Hopefully, it's the latter.
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post #15 of 89 (permalink) Old Sep 6th, 19, 9:18 PM Thread Starter
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re: ZZ4 upgrades?

Quote:
Originally Posted by blue_69_malibu View Post
The Hot Cam and Springs are a great upgrade....but you're not ready for that YET.

Instead, find a local dyno shop that still works on carbs and have your carb AND ignition tuned.

You have a real 350 HP V8 and 3.73 rears gears. You should be shredding tires at will off the line. Either your motor has a fatal injury....or your tune just sucks. Hopefully, it's the latter.
I have a local restoration shop with a dyno. Will give them a call tomorrow. Going to a car show tomorrow as well. Maybe I will run into someone with more knowledge than me. Shouldnt be a hard task...lol.

If it's not broken, let's fix it till it is.
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