IROCtheRoad

Hello all.

Long story short. I bought my 84 Z28 (L69, CCC, etc) and was only getting 11 mpg on the highway. I attributed this to old sensors and a 327 Corvette cam that was installed by the previous owners on the engine rebuild. I had a shop plug and OBD1 reader and all the sensors were working which to me meant the cam was overkill for the 305

I decided to remove the engine and start from scratch to include rebuilding the original CCC. While rebuilding it I learned my secondaries were stuck open causing my over excessive fuel use. I put the now fixed carb back together with all adjustments set back to the factory spots.

The motor is back in with ported/polished 416 heads, XE262 cam, headers, RPM intake, and all the goodies and has been broken in with initial timing at 8 degrees.

The problem:
My plugs are black and fouled (they and the top of the pistons were covered in black soot when I pulled the engine, so same problem but much worse) and the few exhaust leaks I have have unburned fuel coming from them. My eyes burn when I start the car and now not all cylinders are able to fire due to too much gas.

I've adjusted everything that I can but I cannot figure out what would cause so much fuel to be dumped into the car. I wasn't even aware a quadrajet could do this. For giggles I tinkered with EVERY adjustment short of the floats while the engine was running but to no avail.

Solution:
Contrary to a few would say, I'm 90% sure I'm going to get rid of the CCC system. Yes, it is a great system when it works and I know all the benefits but I'm at a dead end with everything. All sensors are connected and working.

Option 1: I really like Quadrajets and have gotten to understand them. I'm thinking about getting a rebuild one from SMI. This will allow me to use the carb on any future engine upgrades and I already have all of the necessary brackets/linkages.
Option 2: Demon Carb's new Street Demon seems tempting to try. My only complaint is that I will not be able to use the parts I've already bought for the linkages.
Option 3: Summit brand 600 carb. I've read good reviews from actual users and am willing to give it a try.

Any advice would be greatly appreciated. If anyone knows what could be causing my torrential flood of gas any and all suggestions will be attempted.

Thanks in advance.

Mortorq

IMHO, SMI does great work.

I spoke to Sean to order a Quadrajet for my 406, 9.0-1, 212*/218* @ .050" .487"/.495" hyd roller unit for my '79 Corvette.

In short, it works fantastic, with a non-scientific very noticeable seat-of-the-pants improvement, easier starting and smooth secondary transition @ full throttle.

IROCtheRoad

It's always nice to hear somebody with personal experience from a vendor.

IROCtheRoad

I've done some more research and my symptoms are extremely similar to a stuck float. I'll take the stupid thing apart again and see what's going on.

I'm still looking for alternative opinions on carbs though.