Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
17056228 First Test
blazer74:
Will do, Thanks
blazer74:
Hello, Checked the primary throttle plates and they close fine. Tried another throttle body I have that is set up the same and still have nozzle drip if I use ported vacuum. Go back to straight vacuum and can stop nozzle drip. Drip starts on passenger side and drivers side drips just after that.
Using straight vac, 6 turns idle screws, 2 turns apt 72 jets, cliffs 44 rods, acc pump outer hole. idle 800 park, 650 drive, vac 14.5, 10 deg initial.
Now runs good, no stumble, pulls hard thru secondarys. Does still have some sooting of tailpipes and some black smoke . Going to try 71 jets and see what happens.? Also added edelbrock 3/4 wood spacer and helps with heat soak but didn't notice any other change.
Thanks Craig.
Cliff Ruggles:
Good news. Going back over the basic engine combination, the cam is a tad much for the "low" compression 355, and ground on a 111LSA.
882 heads are poor performing heads, with very restrictive exhaust ports, and huge combustion chambers. Even with the flat top pistons the static compression ratio is probably around 8.5 to 1.
A set of Vortec or SR Torquer heads would be a BIG wake up call for the engine. It would idle better, less timing needed everyplace, and more power at every rpm.
I've ran into what you are going thru a few times. Takes some effort to get everything dialed in, and often we are chasing the fuel and timing curves around quite a bit to make the engine happy.....Cliff
blazer74:
Hey Cliff, thanks for going back over my info again. definitely agree on the heads, and step down to about a comp 268H cam. I need to pull a head a take some piston measurements to truly see what size cc head I need to get to about 9.1 due to not having specs on my current pistons (older trw's) Too hot right now for that with this 100 deg weather. But then again maybe its time to build a 383 or 400.
Thanks again Cliff for your input. invaluable!
Cliff Ruggles:
I'd stay away from any cam on a 110 or tighter LSA. There are some EXCELLENT cam choices out there for SBC's. I still have to this day to find a better cam for a 355cid engine with about 10 to 1 compression than the old 327/350hp cam. It has 222/222/114 specs, over 300 degrees of seat to seat timing. Idles pretty good, strong power from the moment you load the engine till you decide to shift it!
There are a couple of Melling cams that work just as good, with similiar specifications. The 280 duration .480" lift on 112LSA is a good one as well. These cams need at least 10 to 1 compression to be happy, but will lower the dynamic compression enough to use pump gas without any issues.
Another very good choice, is the GM LT4 Hot roller camshaft. It's a nice upgrade, and will produce over 1hp per cid with a good set of heads on a 350 engine.....Cliff
http://www.jegs.com/i/GM-Performance/809/24502586/10002/-1?parentProductId=761656
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