First off, welcome to CHR David. Hope you find us helpful and that you stay a long time!

Bent pushrods are never good – they are always bad. Was there a significant event just prior to the noise starting (like a missed shift and a real high rev – if even for a few seconds?) There are a couple easy answers and a couple not-so-easy ones. One of the most common reasons is a lifter failure or wiped lobe on the cam which allows too much clearance and allows the pushrod to get off center and pinch causing a bend. What does the existing cam look like? Are any lobes flat or even the slightest tinge of blue? What are your existing rocker arms? Is it possible that your rocker arm studs have backed out (come loose)?

You said the carburetor was leaking. Was it at the base? It’s also possible that you have some sticky valves that are holding thing up (which would cause pushrods to bend) as well as blow pressure back toward the carburetor and cause leaking. Did you do a compression test before disassembly to check for leak-down on the cylinders in question?

What we don’t know is what your pistons and head gaskets are (so we can’t tell what clearances may be there) and there’s also a possibility that some damage has been done internally as well. As a minimum, I’d pull the heads and check for damage – both in the cylinder and on the combustion chambers. I have seen real damage done when something very tiny (like a small screw) gets trapped between the valve and the seat and wreaks havoc on the valves, the head and in some cases the piston. You really need to remove the heads and check everything real carefully and find out where the bind is or you’ll trash your cam and continue to bend pushrods – possible doing considerable damage.

As to your new cam – profile is fine but you may want to consider a roller as the additives in modern oils (or lack thereof) have provided real challenges for proper break in. Pat McCarthy will hopefully chime in with more information and he’s really the wizard as far as engine building with special emphasis on big blocks. If you do go with the flat tappet follow the installation instructions to the absolute letter and use their (Edelbrock’s) break in lube.

Again, welcome and let us know what you’re finding,
Glenn