curious if thie 1948 front and rear are desireable to run in a warmed up Merc flathead???
The front end is not much of an issue as far as design goes. It does need to be in good shape as far as the bushing, shackles, bearings, tie rod ends, etc goes.
The drive train is more a factor of how it is driven than the power out of a mildly modified flathead. You and break it with a stock engine and they have been driven for years with OHV conversions. The rear axle is not going to like "dropping" the clutch and spinning the rear tires! And the transmission isn't a fan of "speed" shifting.
If you are wanting to drive it a little harder and keep the look of the original rear end, there are modifications that can be made that greatly increase it's durability. Might take a look at Hot Rod Works
https://www.hotrodworks.com/product-...e-conversions/
The original brakes are Lockheed. They can work fine, but are a bit difficult to adjust. If you can afford the upgrade, I would suggest going to Bendix brakes. This is what Ford did in later model years. There are complete conversation kits that are close to bolt on.
Steering is the same as the front end, it works great IF it is in good condition. And not so good if it is worn out and/or out of adjustment. They are fairly easy to rebuild and to have rebuilt.