Turbo ls3 vs 427

[1985olds]

Good afternoon everyone,

I'm planning a new engine for my 6 speed g body. I have two blocks I can use, either an ls3 block that I would do forged rods and pistons with a billet 7875 or a darton sleeved ls3 that is ready to be a 427. The car is mainly a street car, I do power tour and daily it in the summer. I'm looking to one day get back into auto cross. Current setup makes 500 whp, but im looking for more. Which would you build?

[1985olds]

To be clear, I'm talking turbo ls3 vs na 427

[Vimes]

Of the two, my preference would be the NA 427. Boosted engines make more heat and are more complicated to work on than NA engines. A turbo, piping and extra cooling gear take a lot of real estate under the hood. Just getting at the plugs might be a nightmare. An NA 427 under the hood is clean and simple, and costs less to boot. NA racing, since you want to get back into it, doesn't have the same sort of heat soak issues a boosted engine does. Plus, you can say it's a 427.

What's more, if the NA 427 turns out to not be enough, you can always toss a turbo or two on it. :twothumbs

[andrewb70]

I would be inclined to stay NA as well.

Andrew

[79 Camaro]

I did a LS2 block sleeved with Darton sleeves from Race Engine Development. Stroked to 427 cubes. Medium cam and it did 500 rwhp. Not huge numbers but was a dream to tune and ran great. I used LS3 heads. Maybe AFR heads another 40 hp?

[andrewb70]

I did a LS2 block sleeved with Darton sleeves from Race Engine Development. Stroked to 427 cubes. Medium cam and it did 500 rwhp. Not huge numbers but was a dream to tune and ran great. I used LS3 heads. Maybe AFR heads another 40 hp?

A combination like that makes for a great street car! I like big cubes and mild cams.

[1985olds]

Hmm, more to think about. Over on ls1tech the consensus is opposite. Thanks guys for the input.