79 K10 350 vortec
 

Hey guys! New to the forum, not classic chevy! I've recently bought a 79 K10 short box with "400 sbc"!
Upon getting the block casting number it's turning out to be a vortec 350 (96 and newer). Casting number 10243880.
So far I've replaced the entire wiring harness (bumper to bumper) with a 21 circuit. The chopped up, hacked into harness was stupid to try and get the lights working.Yes, everything was tested and verified before my first and last trip (24 mi round trip) to work.
Now, as I'm the old school knowledge of chevy and timing with the distributor, I brought the crank to TDC and popped off the cap. 90° advanced. I did this because I removed a few plug wires while routing wires I wasn't satisfied with and forgot where the went. Easiest is start at the beginning right? So, TDC on the crank, drop the distributor back in. Boom, fired right up but seriously rich! Seems to "surge" at idle, no load. Now if I unplug the pcv valve or the brake booster line it clears up and leans out some. My vacuum advance is hooked up to the timing port on the carb (was running straight vacuum from previous owner).
My question is what or where should I be "dropping" the dizzy in for the "closest" timing on this engine? Am I to far retarded from timing at TDC? I've read 28-32° timing btdc is what these motors like.

350 vortec block #10243880
​​​​​​street dominator intake
summit 600 cfm carb
13-18 on vacuum gauge
As of right now, that's all or most of the info I have. Let me know what else anyone would need to help point me in a great tuning direction and I can get it posted.

Any help is greatly appreciated as this was supposed to be my daily driver.

Well, considering that you are running a OBD II 1996 Vortec 5.7 liter that was fuel injected, with no vacuum advance nor centrifugal advance distributor, and no ECM, what are you using for a fuel pump, since a 400 small block had a 16 PSI pump on the front of the block? Yeah, I know you have a carb, but you may have to do some serious adjusting to get this engine to run leaner. Likely have to rejet it some, perhaps lower the floats, I'd wager. Running rich will just wash down your cylinders and wear out your pistons, cylinder walls, and the rings and put too much fuel the engine oil.

I can say the truck has an electric fuel pump set at 2.5-3 psi while running. Fuel level (floats) are set at half the sight glass on the primary bowl and just above the bottom of the sight glass for the secondary bowl.

Jettings are likely in need of replacement to lean it out
then.Back in the day it was commplace. US car makers
would even jet a carburetor to be shipped and sold in high altitude areas of the US like the Rocky Mountain range.

I've re-timed to TDC and dropped the dizzy back in. I did not hook up the vacuum advance. Pulled the top off the carb and pulled the jets.
Primary side has #67
Secondary side has #73
Summit M08600VS 600CFM elec choke
​​​I will be firing it up today with #61 and #67 jets respectively. Then setting the timing with the light.

Good deal. Proper jetting is a lost art with fuel injcted engines.