Toyota Hemi?! Toyota Hemi. 5M-GE: Two valves per cylinder and the wide, agressive valve angle gave this thing good low end torque while still retaining some revviness up high.

As well, the Lexus 1UZ-FE 4.0L V8. One of my favourite sounding engines, bar none.

An engine that runs

DSM 4G63t

The new ones are taking the "fun" out it, coming with forged internals and stuff :(

I'm not sure about favorite but I like..
The LQ1. Someone hit 257 whp n/a with one of those.
The vq30 & vq35 engines. Those engines have alot of options when it comes to swapability. For instance, IIRC the vq30 has 3 upper intake manifold to choose from. 2 of which are variable. vq35'* have a few options as well. Not to mention you can mix, match and frankenstein the crap out of those engines.
The SHO Yamaha motors are pretty sweet and newer Beemer engines have me amazed.

67 400cd Ram Air I
or

71 455 SD HD Round Port


ken

Vortec 5.7L
Ford 4.0L V6, BULLETPROOF
I-6 Cummins
Powerstroke V8
LS series V8'*

I'm sure there are other'* that I can't think of...

,sbc 350, 383, or 400

No doubt about it the mighty L 72.

LS_ series motors
and of course there is nothing like a carb. GM big block.

5.9 6BT Cummins