OK I drove the olds today with a 455 that’s been built basically to 1970 W 30 specs. Car is been running great lately plenty of power. I picked up an extra dwell tachometer today and thought I would see if it was working. Put it on the Oldsmobile, then noticed that it was way off on the reading. Grab the wrench and adjusted dwell on the run, Couldn’t seem to get the needle close to where it should be without the engine dying, dwell should be between 28 and 32. I set back to where I thought it was close to when I started, test drove car and everything seem to be fine except on hard acceleration the car falls on his face above 4000 RPM. After several more Attempts no change, Then on next attempt to change the dwell car died and wouldn’t start, barely move Allen wrench and car started, can’t move wrench any at all One way or the other without car dieing. Cleaned and reset points with feeler gauge and car starts. 😆 test drove car and it still falls on its face on hard acceleration, then did the same just driving down the road anytime I got over 4000 RPM! Look down throat of carburetor to see if I was getting gas I noticed that one of the Jets was only delivering half the fuel it should, I’m thinking maybe it needs a kid in the carburetor? What a day! One step forward two steps back. Is there a good HEI set up for use with Edelbrock 04B intake and ram air induction breather?

 

Dwell adjustment changes ignition timing. Ignition timing adjustment does not affect dwell. Anytime dwell is adjusted the ignition timing must be checked/adjusted. What is the dwell reading after gapping the points with the feeler gauge? Used points don't gap accurately with a feeler gauge due to contact surface pitting, it's better to use a known good meter especially on used points.

The symptom described sounds like it is running out of fuel. Is the fuel filter clean and are the hoses in good shape including the ones at the tank? Run a fuel pump test or try another pump.

Good luck!!!
​​​​​​

 

First Guess: Defective dwellmeter.
Second Guess: Dwellmeter set for 6 cylinder engine instead of eight.


You've ruined the points. Points come with a tungsten coating on the contact surface. You file them, you destroy the Tungsten coating. You knock-off the little cone of transferred metal, you reduce the surface area. Install new points.


If you put a kid in the carburetor, Child Protective Services will arrest you, and take the kid.

"I" would open the carb up, and see what's plugging that passage. I've seen flecks of rust partially-plug a main jet; remove the carb top and fifteen seconds with a tweezer removes the "plug". Put the carb together and it runs great. Other times, there's crap in the passageway beyond the jet, and it takes real work to clean it out.

No idea on the "ram air induction breather". When I had an O4B on a 455, I needed to grind a little clearance into the rear runner, and grind a little clearance into the underside of the distributor to match. Worked fine.







Sorry--no photos of the underside of the HEI where I trimmed it.

Saved me a bunch of typing. Thanks.

 

Check the power piston and float level on your carb.

 

Change the points I see worn down points and carb kit needed.
Gerald

 

What carb? Rochester, Holley?

 

Start with replacing the points and use the known good dwell meter and start from there before anything else.

 

funny you should mention that, I replaced the points and put a kit in the carburetor today and problem solved, Thanks to all for the advice and help

 

If you buy a MSD or Mallory Unilte, they will clear the O4B. Factory HEI wont clear without grinding intake and distributor. Pertronix makes an electronic module to eliminate points on the stock distributor