Chevy 350 people get in hurrrr

COMP XE268H-10
Duration @ 0.050" 224°/230°
Lift .477"/.480" with 1.5 ratio rockers
Lift .509"/.512" with 1.6 ratio rockers

As long as your valve springs and PTV clearance are okay I say go with the 1.6 ratio rockers. If you have to buy them anyways they are the same price. COMP has nice roller tip chrome moly rockers that are inexpensive for a budget build

2" carb spacer will add plenum/intake volume and will help with low end torque. It would be a great addition on a heavy car like you are building the engine for. Edelbrock performer is a nice intake. You might be happier with the Airgap Edelbrock intake however it is a good penny more $$$

Mufflers depends on what kind of sound you like and how much you want. Dynomax, Flowmaster, Spintech, Magnaflow and Hooker all have great mufflers. I purchase mandrel from spdexhaust.com They aren’t the cheapest but the quality is top notch and you have order different bend radius