Secondary's:
About 7 years ago, I was blessed with the best car I ever owned, a 69 el Camino SS396. I'm retiring with this one... It's worn in like me and I really like it has a 1977 454 truck motor with a 400 Turbo and 2.73s out back.
This motor runs real strong. This Quadrajet has never given me one lick of trouble.
It recently started backfiring when the secendarys are opened. With them disconnected, it runs perfectly. The vacuum gauge needle goes to 6 or 7 when floored then cames right back up upon throttle release.
It has its original HEI distributor. I disconnected the vacuum advance and run 18 initial with 30 mechanical all in by 3000. It runs best like this. I use BP or Exon 87 octane. It's suppose to have 8.0 or 8.50 compression and I very rairly ever heard a full throttle ping. The pinging goes away after flooring it a few times. I'm thinking this must clean the chambers out and lower the compression.
It's city driven (Pittsburgh), so the chambers develop carbon and raise compression until I blow it out on the highway.
Yesterday, I pulled the secendary hanger (J) and it was bent.. One rod DN - Passenger side, was almost a half inch higher then the other!! I think I did this installing a lock nut on the air cleaner stud. When I open the secendarys it makes a wierd popping sound I think its running lean. I tried to straighten the hanger out but it still is rough but better..
The carb came with the engine. The engine came from a Book Mobile truck that was demolished with a few thousand miles on the clock. The prevous owner bought the car with several others from Texas in a package deal. It didn't have an engine or transmission. He had this 454 and th-400 sitting in his garage for decades. He kept it oiled and removed the rockers to save the valve springs.
The motor runs like a charm very strong, burns rubber anytime I floor it, even at 40 mph.
