I have a 383 stroker in my 67 camaro with MSD pro billet 85551 distributor with 6A box and blaster2 coil. Holley 750 double pumper w/ vaccum secondary.

The thing is I had it on jack stands for a month to redo the front end. I started it up and it ran and idled good for 10minutes. Then I took it off the jack stands and it wouldnt idle right. It started spitting out the carb. So I took the distributor off and put a new pick up on and cleaned the reluctor(both were pretty rusty). Now when I start it, it pops in the muffler. Its not 180 out and it was at TDC Ive triple checked!

Soo heres a few thoughts ive had.
1. Bent valve- which im dreading and want to check EVERYthing before taking the heads off. They have been redone by a speed shop once already for bent valves.

2. Vaccum leak. Ive always had problems with vaccum with this car. What should the vaccum be on the 3ports on the carb? Its idling ruff so I cant get a good reading. I think there suppose to be 15+? Im getting diffent reading at each port

3. Some kind of carb issue? i know enough how to set a carb but im no expert!

4. Cam end play? When the cam was put in I was unaware of the importance of cam end play and didnt measure the space..

5. Maybe the pickup is gapped wrong in the distributor?

ANY help or suggestion is GREATLY appreciated!

Thanx
Dave

 

If you suspect an intake valve hanging open, you can crank test it with the ignition disabled so it won't try to start. You open the throttle and listen in the carb for a whoosh sound as you or someone else cranks it. If it's one valve, it will be out of cadence where it will sound like it cranks faster for one compression stroke as the valve isn't sealing the cylinder. Exhaust is harder to do this way but you can use a piece of paper over the exhaust sometimes as an aid to see what the pulses are doing. Sometimes a cold engine will show some symptoms and a warm engine will be OK.

Manifold vacuum will me measured by the port below the throttle blades, not the ones above. If the needle pulsates, that can indicate a valve problem also.

If you're sure the timing is OK, check the carb out for float level and leaking needle & seat and if you have the bowls off make sure your power valves aren't blown out.

If nothing else works then check the timing chain somehow.

 

Yeah I was planning on doing the paper on the exhaust thing tomorrow when I have someone to crank the car for me.

Question- I changed the pickup and just sanded the reluctor wheel clean. I just eyed the gap before I changed it and put it back to where I thought it was before. Could a very slight gap difference be causing it to pop in the muffler like fireworks going off? Im planning on pulling it apart and actually gapping it to spec just to rule it out.

When the car "pops" out the muffler its not a constant beat. Its very random and even quits for a minute and as soon as I think it has stopped it pops again.

 

Seems more like a fuel issue than ignition the way you describe it although you shouldn't overlook the possibility of a cracked spark plug or burnt ignition wire because that could cause some unburnt fuel to get into the exhaust.