Just as a follow up, I tried a carb with more bypass air, set up for a bigger than stock cam. It made a little difference, but not the answer I was looking for. I think I'm going back to the drawing board on this one. Might start from the ground up, or might start with a cam swap to see if that does the trick.
So here's the latest. Still wasn't happy with the most recent Q jet build. Seemed to still lack low end power, still had a little more rumble at idle than I cared for, hard starts etc. However, recently moved to Lincoln Nebraska and just this morning took the car into a local performance shop. The guy called me 5 minutes after dropping it off "Dude... your transmission is never shifting into first gear. Put it into first gear manually, and it lays down rubber rolling at 20mph!" So... I've been driving between 2nd and 3rd gear now since the transmission and engine were both out of the car for rebuilds. That explains no low end torque and what an easy fix... He will be adjusting the governor and valves to function properly So, progress is being made... however I still have yet to get the idle quality I desire, and this technician identified some valve train noise. Think I'm going to get some new rocker arms to replace the originals. Should I spend the money for the roller rockers? or just a heavy duty stock pair should work? He is going to put a wideband A/F sensor on the exhaust to see what adjustments would need to be made to the carb. I'm hoping for some valuable feedback. More updates to come.
As someone who just rebuilt a 350, my 71 is now at 9:1 compression, running a TA 212 cam, TA Stage 1 intake, stock heads with a little shaved off for 54cc, block decked .020" and Hooker headers with an Auto Gear M23Z (2.98 first gear) and 3.08 rear gears. It barely has 100 miles on the rebuild and I just got it done before the GS Nats. It has an Everyday Performance QJet tweaked for my cam and compression ratio. It runs well, idles with just a slight rumble and with a 4-core brass radiator and 7-blade clutch fan, it barely reaches 160 in hot traffic. Being a 4 speed car means I don't converter issues. I'm still tuning on mine but I wish you all the luck. I follow along vicariously, knowing I was almost in the same boat. I originally had a much hotter cam I bought off a board member but sold it before I let my appetite get the better of me. Here's my TA 212 firing up with open headers after we got the cam broken in.
I don't want to hijack the OP thread but she seems stronger than the 91K mile, worn-out cam. leaking everywhere, M-21 equipped slug it was when I bought it in 2014. She's already capped up and sounds nice. Here's my wife driving a stick car for the first time in 30 years.
Sounds awesome! love the sound of that idle, has a bit more than what I would expect from the 212 but sounds really good! What is it idling at? sounds pretty low Another update on my journey with this 350. Picked it up from the mechanic today. He was able to tweak the carb a bit, double check timing, add ported vacuum advance to the distributor ( had tried this before but for some reason never had luck with it) and after he adjusted the kickdown cable we now have first gear! Drove it home 20+ minutes in 93 degree weather and the temp never broke 190. (thermostat is 185) Still think I am going to try to add bypass air to the q jet. Shes idling better now but at 950-1000 rpm in idle I think I can get it to come down a bit with some more bypass air. Going to try that over the next couple days, but it finally feels like I have some drivability back in her. Cant wait to enjoy it a bit over this summer just in time to tear it apart in fall for metal and body work.
It idles about 650-700 RPM. I'm just glad I didn't go with a bigger cam for such a simple street car. This whole project started out to be a regasket, headers and new exhaust. It has snowballed, as they often do, to rebuild, new cam, trans, clutch, yoke and everything else that goes with it.
