Just thinking about my set up and wondering about just running stock manifolds vs. w/z manifolds or headers.
I don't think I really need to be worried about the missing 20-30 hp
by not running headers. Since its a rag top and won't be a regular strip car. I'll be real happy with a stout street car and slightly quieter cruising.

So my big question is will there be issues with not using headers with a
JM 20/22 cam?

Has anyone seen or heard of a dyno test from stock manifolds to W/Z's
From all I've read it may not be worth the price difference.

 

That cam doesn't need headers. No cam NEEDS headers, unless you're worried about squeezing all the performance potential out of high RPMs.

For the way you describe your car and your usage, stock manifolds are the better option. Headers make a host of routine maintenance tasks more difficult.

 

My high school car, '72 Supreme had a cheaply built 455 w/ a JM 20-22 cam, stock iron intake manifold, Demon 750 carb, and W/Z manifolds. It ran 13.80 all day long.

I put headman headers (price) on it and ran 13.002 on BF Goodrich 295/50 white letter street tires, up to you. JMO, headers let that cam and "stock" build combo really wake up.