Newly fired BBC...exhaust shaking on left bank only

[Freddie]

Right side exhaust pipe at rear of car smooth stable and unmoved

Left side wobbles all over the place

All hangers checked and all good.

I also have a "whistle" coming from the left hand side exhaust, it increases as RPM increases

I'm thinking a leak / gap in header collector to exhaust flange gasket or I haven't sealed the pipes well enough up to the heads...

any other thoughts ?

[barnym17]

Is the engine missfiring or running well?

[BillK]

Both sides are connected to the same engine. If one side is solid and the other side moves around it sound to me like the left side is not supported correctly somewhere. You need somebody to grab hold of the left pipe and shake it around while you look to see where it is loose.

[54chevkiwi]

Left engine mount bad...?

[Freddie]

Solid mounts - they are all good. It does have a slight misfire every 20 secs or so that I am trying to track down. Yeah I agree same engine how can it be engine related, esp when the engine (at idle) is basically unmoved. more to look into...I need to get under it

[69427]

It doesn't by chance have a 4-7 swap cam?

[mag2555]

If you crank it with the spark killed is the cranking rpm steady, or does it speed up going by a particular cylinder?

[In-Tech]

I'd throw a $1 bet the ex valve to guide clearance is too tight.

[Freddie]

OK so exhaust fixed. It was a hanger. looked OK on basic inspection I went all over them with the car running and one was cracked (metal part) and when still it reseated and looked OK.

Now to figure out the whistle. Definitely sounds inside the engine. I might pull the carb and freshen it up and ensure there are no vac leaks. Might be a pin hole leak in a casket or something like that