Anyone want to try to guess what just happened to my 383 car?

Driving home from Woodward last night. On the highway, about 70 mph, 3200 rpm. Nice night, running great. ALL OF THE SUDDEN....lost power as if I stalled, then BANG, an extremely loud backfire out the exhaust. Ran "alright" afterward but with less acceleration power.

Got near my house about 15 minutes later, got off the highway and the car immediately stalls. I play around with it by the side of the road (swapped orange box, ballast and coil) and it won't start until, later, it finally does but after what I think was the engine cooling down. But now it sounds like something barely audible that is "rattling" or slightly knocking from the motor. There is no readily heard miss, I just "idled" it home and in to the garage.

I know I broke something...probably valve train and maybe other collaterial damage. Just interested in ideas of what I did before I start ripping in to it.

Got any? Bone stock 383, only an Edelbrock and electronic ignition as mods. Oh...to add to the fun, it was after midnight. Also, I have to recognize the Northville, Michigan police, who kept coming by to see if I (and my wife who brought the parts up) were OK.

1. Timing chain skip/broke tooth?
2. Sheared pin of the front of cam allowing it to slip out of phase some, resulting in valves kissing the pistons?
3. Broken rotor under distributor cap?

Let me think some more, I may have others.

Broke valve spring / retainer / keeper. Pull the valve covers first.

After(as said) taking a peak under the valve covers I'd do a compression test

I initial description has me thinking the bulkhead connector, specifically the ignition circuit unless you lost headlights/radio/etc. at the same time, then it would be the main feed.

That could cause more problems if the ignition came back with cylinders full of fuel.

Check the bulkhead then the engine. I agree with pulling valve covers and doing a comp check.

roll it over by hand and check damper at TDC,look at the rotor and see where its at compaired to #1 plug wire

do that first,then pull vc and check for bent push rods,broke springs,retainers

check the springs before trying to run it any more,so it dont drop a valve if one "IS" broken

then do a comp test

post results and finding please

I'm guessing it slipped a cog on the timeing chain...

I concur with all previous posts first . But if the car layed down then kicked back i would have to ask is the fuel pump leaking into the crank case and did it blow up in the block and just think it was from the exhaust. my wife had this happen several years ago the car ran when it cooled but the valve covers were junk and the vally pan was destroyed but low fuel pressure made the car seem weak . c

This seems like a possible electric issue, possibly some kind of power wire providing power to the ignition box may have shorted, or burnt, causing a weak feed. This may cause it to get some power to the box, but not as much as needed for max performance.

This has happened to me before. Crusing about 70 on the hwy; next, I lose fire and get a large pop out of the exhaust. I stop the car and open the hood to find an alt power wire that runs to the wires providing power to the ignition box smoking. Being in a hurry to get to a cruise I was going to, I cranked the motor over and it fired up. Ran ok the rest of the day, then acted up, just as I got the car into the garage. This is when I found the carnage. Another wire it the connector on the right side of the motor arched off of the alt wire. Both had very small slits in them, explaining why they arched.

I replaced both wires and have been ok since.


If it isnt electrical, I would look at upper valvetrain, such as a rocker, or broken spring. Check electric and valvetrain, to be safe.

Does it continue to stall or "die" after the engine gets hot, then only starts after sitting for a while and cools down? If so, my first guess is the pick-up coil in the dist. Next time it stalls check the ohms on the pick-up before it has a chance to cool down and make sure it's ok.

First update...

Today I did all the mechanical checks...

Engine turns over nice and easy with the plugs removed, no sounds or tight spots.

Distributor gear lines up with the crank correctly at TDC, so timing chain seems OK

Took the valve covers off, everything is intact.

Did a compression check, all was remarkably consistent and good.

Thank God! Seems like mechanically I am OK.

Tomorrow I will play with the electical. One thing I noticed...the distributer rotor to cap wear doesn't seem right. The end of the rotor and 8 contacts on the cap seem unusually worn for a car not driven much.

Harness is original and also getting too old, may have to spring for a replacement. The firewall junction block does seem OK though, tight and no burn marks between the connectors.

As I noted above, I did replace the coil, orange box and ballast and yet the car didn't start until after it cooled. Odd. Distributor does seem suspect (not much left to swap!)

I wont pretend to tell you I have the answer. But when you described your problem it sounded exactly like what happened to my Challenger years ago. The only main difference was that I was doing 95-100mph on the highway for an extended period of time (yes, I was driving like an idiot).

Anyway, car was driving fine at a nice click, when I lost power and heard a bang. I let off the throttle. Car was still running and heard nothing more. Gently got back in it and drove the other hour home from the Ozarks. When I got off the highway, I stopped to pick up a soda at the local fast food joint and noticed the car was making a rattle. Sounded like valve train. By the time I got home it was more noticable. The next morning I had trouble getting it restarted. I thought it was bad lifters so I changed them all. Still did not fix the issue, but it was at have the engine speeds as the motor sound. I was never happy with the motor after than and ended up having it rebuilt into my stroker. Still dont know what went wrong, but my piston skirts were all scored and I found the cam difficult to get out of the bore. Other than that, it is still a mystery. Ive heard of torque converter ballooning but dont know if that happened here.

Just because the bulkhead seems tight doesn't mean the connectors are tight. You need to look closely and the dash harness end. The curled over parts will open up and need to be closed back up. It's a lot of work, but it will take care of lots of gremlins.

A YO harness is never a bad investment if your hasn't been replaced before.

I got one for my 69 RR for 85 bucks this summer with the Moparts discount. A KILLER piece.

Same thing happened to me in my 69 RR 383. I was racing (I know..I know) a z06 vette (that was stupid..I know,I know). I hit second gear and shifting into 3rd hard it went "BANG" and next thing I'm over the side of the road (my muffler took a beating) . It would turn over but not start.

Looking at it at home I found out the mechanical advance had jammed and my reluctor had sheered. Somehow the distributor must have wobbled or shifted when I did a bonzai shift.

New distributor and was good to go.

Sounds right to me. To backfire, probably has cam sprocket with plastic teeth worn out.

I would check my distributor now, unevenwear on the inside of your caps should tell you something, possible bad bushing, at high rpm, missfired, could cause you alot of troble and expense, If you have another dist. switch and see what results you get.keep inform..

A similar thing happened to me some time ago and I managed to limp the car home. First thing I did was check the timing and it was retarded but the dizzy was clamped up tight. Turned out the roll pin that holds the reluctor in place has sheared in two and the reluctor had moved on the shaft.