looking for a new cam for my 250. It's in a '52 Chev hard top.
the motor is 30 over with larger valves, lumps, offy intake running an Edelbrock 500 cfm. Tranny is a T-5. I believe the dif is a 3.73
My present cam does not have the low end grunt that I need for pulling my 19' trailer. It has lots of mid range and would rev out higher but I believe that it is limited by the Offy intake.
My present cam is a Shadbolt but I have no specs for it.
I need good midrange and better low end torque.
Any suggestions?

What static CR?
What's your cranking compression?
What valve lash?

It would be nice to know your cams specs you are running now.

Hyd cam, correct?

Does your engine run rough as in a lumpy or lopey idle camshaft?
What is the vacuum it produces when idleing?

You can try a set of Rhoads lifters for the time being.
Should help w/low end,more vacuum.
Just saying,instead of a full blown cam swap.

This will help unless your camshaft is just to radical for the street type of cam. Example .550 lift 220+ degrees duration @ .050 on a 106 lobe center.

MBHD

You can get lift measurements ,pretty easily. Duration can also be measured without pulling the cam.

Without knowing your cam specs, but hearing what you want a RV cam will better fit your needs. Lookup a compcams 252 high energy. It should be the ticket. Tom