So my kid and I have a 86 z28. vin says H model. last year we scored a brand new rebuilt 350 with paper work from auto machine in st. Charles IL. we just had to bolt it together. its a 010 and came out of 1970 gmc 2500. It was rebuilt with the standard cam, and has regular 441 heads. We put edelbrock performer dual plane intake, summit racing headers, flowmaster exhaust all the way back. We had the 305 swapped last fall for this 350 and at that time we left the quad jet carb and distributor in it just to get that complete. Now we are going to swap distrib to a MSD and want to change carb to a holley. I'm looking for suggestions on which to run. A good friend suggested a 670 street avenger. Are we in the ball park here?

 

https://www.summitracing.com/parts/hly-0-6210

 

^^^^
X2 on the Holley 4165.

It'll bolt directly to the q-jet manifold (using the correct gasket that should be supplied with the carb), and like other Holley carbs, it will be easy to tune (jets and power valves are readily available) if it doesn't work perfectly out of the box.

 

Is the manifold you used setup for a spread bore, square bore, or both? Do you like geometry puzzles and fabricating brackets? Running the stock hood?

Anything other than a Q-jet, you'll be dealing with geometry issues with the throttle cable, and more accurately the TV cable for the trans if it's a 700R4.
If the intake is for a spread bore like the Qjet, and its not also designed for a square bore, you'd need an adapter to run a typical Holley like the street avenger.
Stack an aftermaket intake, an adapter, and a non-stock aircleaner and the stock hood won't close.

Rebuilt Qjet for a late GM car without computer controls is a bolt on replacement without fabbing anything. It fits exactly like the stock carb.

 

I'd suggest either the 650 mechanical secondary or 750 vacuum secondary, the 650 will be a little more responsive, but the 750 will run well too as long as it's jetted correctly.

 

Thanks for your reply’s. Sorry I haven’t been able to reply. I’m battling shoulder surgery, rehab, and pain. But anyway an update I didn’t put in post I see. We have auto tranny (700R4) and running a 1 1/2” high x 14” dia. Air cleaner with no problems in hood clearence. Do the secondaries make a difference in not having stick shift? I am going to check hood clearance as soon as I can pick up some putty or clay. I want to see how much we have to play with.

 

If that's the case then the manifold works with the Q-jet so ...
..is the way I'd go. Vacuum secondaries are your friend. And the CFM is right for the CID and application. Hood clearance shouldn't be an issue as you're not adding any spacers or adapters.
Regarding the TV cable geometry, you'll have to pay attention to that detail. Holley makes a bracket that will point you in the right direction.
https://www.holley.com/products/fuel_systems/carburetor_components/brackets_and_linkage/parts/20-121

https://www.holley.com/products/fuel_systems/carburetor_components/brackets_and_linkage/parts/20-121

 

The 6210 is manual secondaries. MUCH MUCH MUCH MUCH MUCH MUCH MUCH MUCH MUCH MUCH better than vac sec. I also had a 9895 for awhile; basically the same as the 6210 except with vac sec (model 4175 whereas the 6210 is a 4165) and it was altogether NOT as good of a carb. I hated that I spent new carb money on it (this was in around 80 or 81) and I just simply should have bought the 6210 instead.

Skinny is absolutely right about the TV cable stuff. I've seen LOTS of problems with some of the "geometry correctors" and various other parts; no idea whether the Holley stuff for this is any better than, say, Edelbrock; but another source of it I www.tvmadeez.com (Bowtie Overdrives). I've only every had these on stick shift cars or once a 6211 (another same as 6210 except 800 CFM instead of 650, not sure if it's even still available) on a 454 with a Turbo 400, which RIPPED. Absolutely ran circles around the emissions-crippled 70s Q-Jet that was on it. Never got a chance to put a GOOD Q-Jet on that car, like a 7029202 or 7029208, so I can't make a direct comparison. I will say however, I will NEVER put a 70s or 80s Q-Jet on ANYTHING I expect to try to make fast. The CC Q-Jets are considerably better than the earlier M4M models, but are still rather mod-hostile, past a certain point. Plus Q-Jet cores in good shape (without dissimilar-metal electrolysis), and parts in general, are not as plentiful as they once were.

 

So it is. Not something I'd use personally but even for drag racing, the VS performs as well as a mechanical version so long as its tuned properly. And I will say, THAT can be difficult.

 

I can speak for the Holley geometry corrector bracket for the 700r4, it works flawlessly. As for a mechanical secondary, I absolutely love the throttle response out of a properly tuned mechanical secondary Holley; I'm running a 950 CFM mechanical secondary and the throttle response is incredible.