Hi all,

I have a '69 coupe with a rebuilt 350, Q-jet, 4spd, no power anything except windows, headers, and sidepipes. I've re-done the interior, added some rear suspension upgrades, new gas tank and fuel filter (in-carb), and basic engine tune-up (new plugs and wires, new distributor, upgraded alternator, etc.).

Quick summary of current issue: Seeming recent loss of snappy, low to mid rpm performance. More recent timing tuned to 14 initial, 36 by ~3500 rpm, vacuum added another ~16 degrees. No detonation, adjusted idle to ~1,000 rpm and adjusted carb using vacuum gauge - showing all was well with engine function - but still feeling a little sluggish at low and mid rpms.

On a recent trip she was running pretty nice then died suddenly at highway speed (~80mph) on a trip after running sweet for 140 miles. Oil pressure was good (40 - 50), water temp was 210, system was charging. Electrics remained when the engine died at speed, I hit the clutch, shifted to neutral, and coasted to a stop. She would not re-fire and would backfire through the carb. I waited for her to cool down some (she never lost any water) and kept trying to start her. I suspected vapor lock or flooding - then had a small carb fire after backfiring through the carb. I put that out with a towel to avoid using my chemical fire extinguisher, though I would have if needed, of course. I suspected a broken or jumped timing chain or issue with the cam or cam gear, so I had her towed to a shop.

Shop said she still would not start for them either - and my distributor was bolted down good and had not moved. They could turn the crank ~3" with a wrench before the rotor moved, so they suspected timing chain/cam gear, etc. However, they said the timing chain was in good shape (a double-roller) and crank & cam gear teeth looked good. They pulled the distributor - but its gear looked good too. So they put it back together and messed with timing until they got her starting / running again. Now she runs much like she did before, though their timing tuning feels a bit different than mine - I haven't hooked-up the timing light again yet.

I'm stumped but thinking about a Q-jet rebuild and that maybe I should start saving-up for a newly rebuilt HO long block.....350, 383, or 427.

Any advice/ideas/suggestions would be most welcome.

I should look at some current threads to see if I can do the same for anyone else - I am way behind on helping anyone here, given the help that I have received from this great forum community.

Best to all,

C3B

 

BF through the intake would lend to lack of fuel ...... ????

 

Thanks hal1phx,

When trying to restart her, I was getting fuel in the front barrels - and the carb fire started when I held the pedal down while trying to start, thinking I had maybe flooded her. She tried to start, but just would not.

Although it cut-out instantaneously (seemingly) at speed, it may well have been fuel-related somehow. Late yesterday, I swapped the carb with a commercially-rebuilt Q-jet that I had as a back-up (I read Lars' paper on those after I bought this one) - and she seems to run somewhat better now. I'll drive some more later today and maybe play with the timing again. She definitely starts better with this fresh, though likely messed-up, carb - both when cold and when hot.

Thanks again.