Dave,
Let's not get confused now...
Originally posted by 53moneypit:
It's just two 351's running in tandem ...
That is only partly true, or all wrong, depending on your understanding of tandem...
A 702 has a one piece block, crank, cam, and oil pan. Although many people think they are two 351 V6 engines bolted together they are not.
They do however share several components with the V6, to include rods, pistons, heads, and most carburetor parts.
The list is even longer for the V12 specific items, including:
block, crank, cam, flywheel, oil pump, water pump, oil pan, water connections between heads, thermostat housing, and even intake manifolds.
Although V6 intake manifolds will work there are dedicated V12 manifolds with the complete 12 cylinder firing order cast in them.
There is a chance some parts that are on a V12 that don't fit a 351 may fit a larger V6, perhaps the oil pump? and I know the rods fit several other V6.
Grigg