The 5.0 l engine bolts into your Pantera. But you'll likely have problems getting 5.0 headers to fit around the rear springs, and your 351C headers won't fit the small block heads. You'll also have trouble mounting the A/C compressor bracket. Most of the swaps I'm familiar with were for small-capacity racing so such things weren't a concern. On the good side, the engine is physically smaller & lighter than the 351C, so once its in & hooked up, you can replace the firewall bulge with an essentially flat engine access cover for more passenger comfort. But beware- torque is addictive and is not replaced by high-rpm horsepower for most. You'll miss the grunt of the larger engine. Before doing this, see if you can get a drive in a 308 Ferrari; a 5 l Pantera will be very similar IMHO.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.