Thanks guys...these are def good starting points. I know it's not the fuel filter or lines as I just had both tanks dropped, recoated, and all lines replaces. I need to check the rest....what is the easiest way to check the muffler/exhaust?

quote:

what is the easiest way to check the muffler/exhaust?

If it were newer, I'd suspect clogged catalytic converter.
Without one, a visual inspection to rule out crushed/kinked pipe should be sufficient.

Aside from plugged convertors or mechanical constriction in the pipes one culprit could be the exhaust heat riser valve.

One side bank of the V8 will have a flapper valve in the exhaust right near the manifold. It is supposed to close when cold to force exhaust from one bank through a channel in the intake manifold to the other side exhaust, thereby heating the intake manifold.

The valve is supposed to open when warm. If it sticks shut it will restrict the exhaust on that side. May be worth checking.

Some have an actuator to move them, some just a bimetal spring on the valve. Example:

We just bought Matt's 1977 Barth. So happy to come upon it this morning and it was only 1.5hrs away. Crushed home on the highways 55+. It's going to be a fun (and challenging) project. We are thrilled.

GirlsInPantsTour ,
Congratulations on the purchase of the Barth .
I'm glad someone is taking on this project to save another piece of BARTH history . Have fun , Bob

Thank you! Can't wait until it's usable.

An uneventful 1 1/2 hour ride home?? That's one heckofa good start

My 454, 82, 25 footer, does well and I like to drive it around 60 mph, pulling a 19 foot bass boat. I have run it faster but then I can watch the gas tank gauge go lower, lol I did put new air springs in it and that helped with the stability a bit.