[Formulajones]

If 600 streetable HP is all you're after, back when I was fooling with this stuff, the popular thing to do was grab the iron 4" bore block and stick a 4" crank in it.
Usually .030 over making a 408. Bunch of those were running around before the after market LSX block really took hold. At that time the aftermarket was scrambling to produce CNC heads and there were a few good ones that hit the market.

Had a few buddies that ran 408's in their 4th gen camaros, with mild gears, and either an auto or 6 speed. They would run 10.60's or so at 125-128 mph and they were very mild street cars. Certainly not 7000 rpm screamers.

I don't remember what the engines dyno'd at but they were well over the 600 mark to move a 35-3600 lbs. street car that fast. Just a nice set of cathedral port heads (The square ports weren't around yet) and a mild hydraulic roller cam. Most used the stock LS6 intake too unless you had the coin for the LSX intake, but again that was fairly new stuff when I started playing with them.

I ran primarily LS1's and had one 6.0 (LQ4) and one LS6. As far as torque goes, that's all relative. Certainly the LS1's weren't comparable to the DZ 302. As a DZ 302 owner and having owned many LS1's I can say with certainty the LS1 wasn't all that bad down low, and even the little DZ does well for what it is, the LS1 just does it better. But a 4" crank in an LS will certainly improve in that department as I would think that would provide enough torque to satisfy if that's what you're after.

For me, the LS1 with a cam and some bolt ons were enough to satisfy my fun factor in our daily drivers. And it was cheap fun. I liked 3.73's with the 6 speed, 28 mpg and on street tires spinning I could dip into the 12's at 114 mph, only had a 224 @ .050 cam in it LOL. Probably dip into the low 12's or high 11's with a good tire based on the mph. It weighed 3620 without me in it. For a 346 they are still impressive. My wife drove that to work daily for years.