I have an '84 Z28 with the L69 engine and I want to remove the existing factory carb and bolt on a Holley. From Holley's web page it looks like the 0-80570 Street Avenger is a bolt-on mild replacment. Besides bolting this thing on, does anybody know if there are any other mods I would need to do to make the carb work with my engine? THANKS!

 

You currently have (I assume, if stock) a computer controlled carb and distributor. The carb is a q-jet spread-bore. The Holley you describe is square-bore, meaning you cannot bolt it to your intake manifold without an adapter (which will raise your air cleaner making hood clearance a problem, promote leaks, and be much less than optimal for performance). You'd be best off replacing the intake with an EGR-style Performer or Action+ manifold.

Since the Holley is not computer-compatible, you will lose the input your q-jet provides to the computer. This means your distributor will not be given advance commands from the computer. To fix that, you need to replace the distributor with a non-computer type that has vacuum and mechanical advance mechanism.

Since your computer is now comatose, your EGR valve, AIR injection, and torque convertor lockup will no longer work properly. The EGR valve can be replaced with a vacuum-only type, as can the AIR valve. The torque convertor control can be handled by a conversion kit available from either Summit or Jegs.

Now, the really good news: After you spend about $600-700 to take care of all of this, you will have a car that has no more performance and which will probably not get as good gas mileage as it did before (or could if everything is working correctly). You will also have an orange SES light glaring at you every time you start it up. To boot, the carb will not flow as much as your current q-jet can. And, if you are now in or will someday live in an area that requires emissions inspection and testing, you will fail.

Your money would be much better spent improving the exhaust with headers, y-pipe, high-flow cat & catback. You could even replace the cam and maybe the intake with one of the pieces mentioned above, tune to optimize your changes (mostly the secondary rods & hangers). Going that route, you will be much better off than just putting on that Holley.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, LT MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1/95.5 @ 5800' Bandimere.

 

Yikes! I had no idea it was that involved. Thank you for that exhaust recomendation. Guess I need to rebuild the Rochester.

 

don't do it!! I have the same engine and was going to do the same thing. I already have headers & cat back, that's a good improvement,an intake & cam would be good money spent too.

 

finally someone who thinks this swap is a waste.Much cheaper to fix the c/c q-jet.Just wait untilyour motor needs replacing then do it,thats my plan.Not sure where in va.you live but getting it inspected will be a problem unless you know someone.The people who claim to have done this without gettin a code/light must ave unhooked the computer.Unhook your m/c with the car running ,you will get a light.

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~mike~86 IROC-Z

 

Dealing with the Holley sin't as scary as five7kid makes it seem. You won't need a new intake manifold (it would be nice) and you won't spend $5-700. A stock replacement quadrajet from local parts stores runs around $350. I'm currentlly using the 0-80457S and it is an excellent product. The only trick to this swap in our area is that for inspection, you must swap back to stock for the visual inspection.

Good to see people from Richmond on the board. Also, be sure to check this place out http://www.mafba.org

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--Steve S--
1984 Trans Am 305 LG4, 5 speed Daily Driver, Flowmaster 80 Series
Holley 600 cfm & vacuum advance
Soon: Edlebrock Intake & TES

 

Ummm... I totally agree with 5.7! I have done the holley swap and it is a major PITA and a lot of $$$! And I would argue that I even know WTF I am doing half the time...

Keep the Q-jet. It works great on your L69 and will give you very good gas milage. If you need to pass emmisions, than keep it. I pass, but I know sme tricks and stuff to keep the sniffer happy.

FYI- "Other Mods" can include lots of misc fuel fittings, pipe benders, and teflon tape. A new vacuum controlled distributor... heck, toss in a spring kit and adjustable advance canister too... maybe a high voltage coil and new rotor too! A ton of vacuum hose nightmares. Sleepless nights tracking down a vacuum leak (which leads to glowing headers!).

It's a lot of fun.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-