Need some help on diagnosing this engine. Runs rough and I can't figure out which direction to go with it.? Any input would be appreciated. Thanks
455
performer intake
Cutlassefi cam 226/230
Holley sniper
Edelbrock heads

 

Nobody wants to take a guess at it? lol I was thinking the valves might need to be adjusted.. I've changed out the plugs and opened the gap a little more. Checked my timing and it seems to be correct...

 

That might be nothing more than big aggressive cam rough idle. The vacuum gauge is steady, it seems to idle like a rowdy cam should. I’m at work (it’s pretty loud in hear, I can’t hear anything on the video).

 

Make a recording at the rear of the car so we can hear the exhaust

 

With all of the noises on your video it's hard to tell specifically what your asking about. The low vacuum can be symptom of the cam and is normal. What you want to see is a steady needle with minimal fluctuation.

 

I don’t listen to a lot of engine running vids but my first impression is that it sounds “ticky.” Could be exhaust leaks, could be valve adjustment, could be engines tend to sound like that in a phone vid.

If there are exhaust leaks, fix them first so you can hear any other noises first. It might also make sense to check valve adjustment and correct if warranted. Valve maladjustment could give you a variety of noises based on tight/loose and that might be something the vac gauge is indicating. These would be two basics that I would start with based on what I can guess from vid.

As mentioned, a vid of exhaust sound at tailpipes might be helpful for people here to give a listen.

 

Well come to find out my distributor cap and rotor needed to be replaced. That simple. I never thought to check that because this was a new engine with only a couple thousand miles on it. Holley dual sync seems to burn out the contact points relatively quickly. I guess I have to change the cap and rotor every time I change the oil. Good to know now but frustrating when trying to pinpoint it. Thanks for the help..