Cliff's Quadrajet Parts and Rebuild Kits

All of the spread bore intakes are pretty close for performance potential, even EGR versions.  If your little SBC is under about 500hp they will run right with any of the aftermarket dual plane intakes even the taller air gap Edelbrock RPM.  You might see a little less top end power but they will make up for it in average and mid-range power. 

Many years ago when I was drag racing my 1965 Nova SS I played around with intakes and found that on the "little" 283 a "modified" 1970 cast iron intake opened up under the carb to the apprx size/shape of an Edelbrock Performer or RPM was the overall winner for ET at the track. 

Even with that said all the intakes I tested were very close, most being within .02-.03 seconds of each other and not much more than 1mph difference.  The larger intakes shifted power to higher RPM's rather and gave up some short times to finish a little harder, so really not much difference or at least enough to worry about with that application. 

The engine was bored .060" over, 12.5 to 1 pistons, 59cc combustion chamber heads, 260 @ .050" flat solid cam, TH350 with a 4400rpm stall converter and 4.11 gears out back.  Shift points were 6500rpms and it went thru the lights just shy of 7000rpms running high 11's at 112-114mph.

I also owned and drove a 1979 K-5 Blazer for many years with a well prepared 406 SBC engine.  I saw absolutely NOTHING playing around with intake manifolds and actually ended up staying with a 1978 truck intake that had the divorce choke set-up as I love the 1977-78 divorced choke Q-jets with the SMAB's.  Since the vehicle was driven year round and used for hunting trips, pulling trailers full of firewood in Winter months, etc it preferred the cast iron intake in colder weather as it held the heat better than any of the aluminum intakes I tried on it........

There is a pretty contentious debate with dirt track guys that the 346249 and 346250 intakes are the best flowing iron intakes. And the later aluminum factory ones are pretty good, with a weight advantage to boot.
I have the 346249 on my 350. I did a fair amount of porting on it, including cutting and grinding the center portion to look like a rpm air gap. Runs good for what it is.

This carb was rebuilt with a kit and recipe from Cliff about 10 years ago and was running great.  Accelerator pump is Viton and working well. 

The problem is fuel has started to drip even thought all throttle plates are closed. This morning I noticed the top of the float is still wet. Not sure if a new float would be wet on top overnight.

Now I am thinking needle seat and float, but I dont know how that fuel is being pulled through the Venturi  when the throttle is closed. The fuel level in the bowl doesn't seem excessively high to me.

One pump on accelerator with cold engine should set the choke 100% closed, no more no less.

With the heat shield installed, and the old spacer, it finally ran decently.  I was able set the idle, and the fast idle also appeared to work correctly and kick down. With the vacuum gauge hooked up, it was showing around 18-20 under light throttle. 

It seemed happy to idle at around 850-900 rpms, but I did notice that at idle it was still running rich. Adjusting the idle screws in further did not appear to make any difference.

On a hot start, it cranks over with no throttle input, which is nice.  On a dead cold start, one pump of the accelerator would set the choke about 1/4" open, but it would not crank over well at all. If any one has pointers on setting up a divorced choke, please let me know. 

I have some bad belt squeal when revving it more than 50%, which I suspect is due to the alternator being misaligned with the other pulleys.

I'm embarrassed about not knowing about the hot slot, but here we are.