[hot rod lee]

I have a 355 SBC with a cam duration 228 degrees at 050" .511" lift inlet and exhaust. the engine is not recenty rebuilt but has stood a while, I have had a few problems getting this engine going and gradually it has started backfiring through the carb, this backfire is in sync with the engine, not random. I have had a look around and found a large clearance on no 4 exhaust rocker and noticed that the lifter does not travel the same distance as others. My theory is that because no 4 is not exhausting the cylinder is still under slight compression when the inlet opens, causing the popping and banging back up the carb.

what are your thoughts ?

 

[The Big Al]

You have whipped out that lobe.
Cam is now bad! Sorry!

it's trash.

Some questions?

How old is cam been in the engine?
What oil?

Flat tappet cams need ZDDP for a period to live!

Al