Working on a 87 firebird 305 and I have the timing set and it idles great through 3000rmps, when I take it out on the road, it starts barking, stalling, running rough, stalls, idles like crap, its a mess when I drive it. any thoughts or help is hugely appreciated. btw all smog and emissions are removed. it is an oldschool setup.

here is the setup
305, edelbrock intake non egr, edelbrock 14xx performer carb 600cfm w/elect choke, msd hei distrib, vacuum advance, single wire alternator.

timing 6btdc static, 12 btdc with vacuum advance attached 15 at 2300rpms.
vacuum lines from passenger side front carb to dist for V/A, driverside plugged.
vacuum line from the rear center of the carb to the brake booster
vacuum line from the main front to the pvc

idles great in park and neutral, step on the brake and the engine cuts down to 500/400 rps, starts to shake some. put it in Rev, back out of the driveway, starts to shake, idle like crap, shimmy and stall.. put it in drive, same crappy thing.

so my question is should I run the brake booster to the manifold and block that rear port? is there a transmission vacuum line I missed? is the dist vacuum on the right port? I thought I had it set per the mfg instrc.

 

You need to set the curb idle speed with the car in DRIVE.
700-750 RPM. unless you have more camshaft then 800..

make sure the choke is fully open when setting idle speed.

chock the wheels and try again.