emissions

[olds307 and 403]

GM did make a performance chip for Chevy CCC systems called the ZZ4 PROM. A member on the MCSS forums named Bitflipper sells ZZ4 clones that he burns out. Very worthwhile upgrade through it requires a 87 or 88 ECM swap. Another option that works on any GM CCC system is Crane Cams rare performance ECM that had dashpots for adjusting the tune without burning PROMs.

So does the ZZ4 actually do anything other than timing curve? I also assume the Crane set up makes part throttle fuel adjustment? Part of the problem on the Olds CCC is it is really lean on the primary side, the HO just improves the secondary side and the timing curve is super aggressive, especially on later swirl port motors, 60+ degrees! The earlier ones are still in the 50's, I believe. This is fine for the factory 8 to 1 motors, not so good for a bump in compression and a bigger cam.

 

[Bonnewagon]

I wasted a lot of time and money thrashing a 307 on an '82 Buick Riviera. After all that it still sucked.

 

[69hurstolds]

If you want performance, you'll have to ditch the 307 along with the CCC. No amount of CCC removal alone will get you satisfied with a 307. You'll be left wanting more. And then you'll have a hacked up car for what? 2 more HP and 0.1 mph faster in the quarter? If you ditch the CCC then also get a 403 or 455 and then you're starting with something.

I still vote no for hacking up a low mile example of H/O history. But that's just me.

 

[Clone TIE Pilot]

So does the ZZ4 actually do anything other than timing curve? I also assume the Crane set up makes part throttle fuel adjustment? Part of the problem on the Olds CCC is it is really lean on the primary side, the HO just improves the secondary side and the timing curve is super aggressive, especially on later swirl port motors, 60+ degrees! The earlier ones are still in the 50's, I believe. This is fine for the factory 8 to 1 motors, not so good for a bump in compression and a bigger cam.

A factory ZZ4 chip has more aggressive spark advance, much less aggressive knock retard, faster recovery from a knock retard, different MCS duty cycle, disabled EGR, disabled BARO sensor, different TCC lockup cycle, and many other minor differences from a standard L69 PROM.

Bitflipper's chip is a little different from a factory ZZ4 PROM, he re-enabled EGR and the BARO sensor while disabling the weird automatic spark advance whenever a scanner is plugged into the ALDL port.

The CCC system doesn't care about displacement. Many Chevy and Olds guys run CCC on larger displacement swaps.

 

[Gonzo1970]

I hesitate to modify a 305/307 much at all, really.. Chip or no chip.. Its just not worth the time and money. You will have more into that 305 for less performance than you would just going 350.

In my case, the 305 had 51k miles. Now its got 62k. (I don't buy cars to park in the garage, I buy them to drive).

But the 305 runs like a top, so I just decided to let her breathe.. headers, duals, and an Edelbrock Performer w/EGR intake, and just run it. It's fast enough for me, and sounds good. Is it the fastest thing on the planet? Oh hell no..

I Mainly chose those upgrades because they would bolt onto a bigger SBC (say, a 350, 355 or 383) should I go down that road.

Big Fat Juicy goal is to build the 200-R4 to handle about 500hp, 3.73 rear, and a Pontiac 6.6L 400 up front, slightly modified.. Its the same set-up I had in my 1978 Trans Am. Was quite the little runner..

But a more realistic goal would be some sort of SBC if/when the 305 goes t*ts up.. But that doesn't stop me from doing, say, the rear end while running the 305.. or the 200-R4 while running the 305..

-Gonz

 

[MrSony]

Nothing says you can't yank the 307 and stuff a 403 or 455 under all/most of that stuff and keep the 307 for later. There was a guy that did that (a member?) And he's running the stock CCC doing I think low 13s. Kinda fuzzy on the details.

 

[TURNA]

Kinda

🤪

 

[Clone TIE Pilot]

I hesitate to modify a 305/307 much at all, really.. Chip or no chip.. Its just not worth the time and money. You will have more into that 305 for less performance than you would just going 350.

In my case, the 305 had 51k miles. Now its got 62k. (I don't buy cars to park in the garage, I buy them to drive).

But the 305 runs like a top, so I just decided to let her breathe.. headers, duals, and an Edelbrock Performer w/EGR intake, and just run it. It's fast enough for me, and sounds good. Is it the fastest thing on the planet? Oh hell no..

I Mainly chose those upgrades because they would bolt onto a bigger SBC (say, a 350, 355 or 383) should I go down that road.

Big Fat Juicy goal is to build the 200-R4 to handle about 500hp, 3.73 rear, and a Pontiac 6.6L 400 up front, slightly modified.. Its the same set-up I had in my 1978 Trans Am. Was quite the little runner..

But a more realistic goal would be some sort of SBC if/when the 305 goes t*ts up.. But that doesn't stop me from doing, say, the rear end while running the 305.. or the 200-R4 while running the 305..

-Gonz

The ZZ4 chip was originally designed for the old thirdgen F body 350 crate kits, it will work great on a 305 for the time being and on a larger motor down the road. I installed Bitflipper's ZZ4 chip in my HO 305 powered Regal and was surprised how much it picked up, it idles smoother and screams when the throttle is opened. Granted my 305 is the higher CR L69 with a mild performance cam swap and headers along with the chip. Bitflipper chages $65 for his chips, which is cheaper than most bolt ons, even used. You can pick up used 87 88 ECMs for $25 or less on EBAY. GMCOPO, is really overpriced if you are going by their prices.

 

[Gonzo1970]

The ZZ4 chip was originally designed for the old thirdgen F body 350 crate kits, it will work great on a 305 for the time being and on a larger motor down the road. I installed Bitflipper's ZZ4 chip in my HO 305 powered Regal and was surprised how much it picked up, it idles smoother and screams when the throttle is opened. Granted my 305 is the higher CR L69 with a mild performance cam swap and headers along with the chip. Bitflipper chages $65 for his chips, which is cheaper than most bolt ons, even used. You can pick up used 87 88 ECMs for $25 or less on EBAY. GMCOPO, is really overpriced if you are going by their prices.

At the end of the day, would you say its worth the $100 to put on a Stock 305?

I dont think this 305 is going to go t*ts up anytime soon.. Im having the carb rebuilt and at that point, I will install the edelbrock intake.. So, Headers, Duals, Edelbrock Performer w/EGR, Everyday Performance Q-Jet.. I hadn't planned on doing anything else to it, really.. but if its $100 and relatively easy to do the swap..

-Gonz

 

[Clone TIE Pilot]

Swapping the ECM and PROM is easy, plus they can be easily transferred over to a 350 or larger engine when the 305 gives up the ghost. Assuming you would keep the CCC system with an engine swap.

How well the engine will respond to the chip depends on the engine specs and other mods. Mine responded well since it is an HO L69, 9.5 CR, 305 with a Crane 2040 cam and TES headers. If your 305 is an early LG4 with 8.5 CR and stock cam, you may not see as much benefit as I did. Later LG4s were bumped up to 9 CR but still had a smaller cam than L69s. Also LG4 carbs have smaller jets than L69 carbs. Big thing is to pick mods that will complement each other.

Worth is somewhat subjective, it was worthwhile for me, especially since I already had an 88 ECM I paid $10 for and my engine probably needed more timing with the cam upgrade. Is your 305 a early, LG4, later LG4, or an L69?