[Streetwize]

I know of no real bottom end problems if you start with a good sonic checked and well machined block. As for quirks, well once the stoke gets in the 4.125-4.17 range, you should be real careful with rod to cam clearence, you want to allow .060" minimum clearance up there, you have to allow for chain stretch, I use a reduced base circle cam along with the quiet Gear drive on long arm motors.

The other thing to consider if upgrading from a 351 is that you need a lot more Airflow out of the heads, I look for a minimum of 280 cfm @.500" valve lift to insure the motor will rev in the 5500 and up range.

You'll love the all-over power and wall top wall torque. To me it's the best of both worlds to have big block power and small block weight.

Also, Please strongly consider a scattershield when running a stick behind a torque monster motor like these. An exploded clutch will cut through a cobra body like a hot knife through butter and the flywheel is about even with your calf (not your ankle) in most Cobras.