Well, that is correct in that the engine from the Torino is labeled as a 429.... however, since there are no decent kits which contain the short production Cleveland 351 (1970 – 1974). I suggested starting with the Torino engine. It CAN be built up into a very believable 351 Cleveland because I did it!
You see, I used to own a 1972 Mustang Mach 1 with a 4 main bearing version of this engine.

I spent a lot of time on my back under that engine in the 5 years it was in my garage and I can tell you first hand that the Torino engine is the closest you will find! You could source the heads from the ’70 Boss 302 as they ARE Cleveland heads… but the differences are so slight as to be nearly nonexistent.
While I had the Mach, I replaced the pan gasket; the timing chain, the starter, radiator, and valve cover gaskets, rebuilt the 4bb carb twice and fretted over the vacuum tubing constantly. It got to the point that I could work on that engine without turning on the freaking light…
Michael "Raisin" Garrett is correct however, that you could use one of the NASCAR kit engines. But unfortunately that will require you to find another source for a correct oil pan, correct intake manifold and auxiliary components. The Torino already has those plus the correct 4-speed tranny. Why make it harder than it needs to be?
The only major modification I made on my conversion was cutting away the forward part of the intake manifold so that the cooling hose and distributor could be mounted directly to the top deck of the block, as this is the most obvious feature of the Cleveland. The rest of the casting is spot on with the Cleveland including the timing cover, oil pan, fuel pump, water pump and block casting details.
Okay? Okay!