8banger

iTrader: (16)

Hey everyone..I have two different ideas for a motor I'd like to build by next year. I've done almost everything on my car so far, so building a motor myself is my goal, so i can expand my knowledge and if all goes right, haul some more ***. I've come up with two options. Here they are:

1.) Aluminum 370 (3.622" x 4.03")
This would be built from an LS2 block, bored .030" over. Stock crank, forged rods/pistons, higher (11.5:1-ish) compression, most likely ported LS6 heads/LS6 or Performance Products Typhoon intake, maybe even a L92 setup, depending on what options are available, I still have to spec out the cam, but I'm thinking something around the size of a G5X3/X4. My goal with this is to have a lightweight, high RPM, mostly street motor, every bolt-on. I want to try (yes, the key word is try) to break 500rwhp with this. I think it'd be a nice spray motor, and pretty fun on the highway.

2.) Iron 421/427 (4.125" x 4.03"/4.06")
This would be built using an LQ4/LQ9 iron block, bored .030"/.060" over. 4.125" forged crank, forged rods/pistons, 11.0:1-ish compression, most likely hand-finished AFR's or ET's/Typhoon or FAST, if not some type of L92/LS7 heads/intake or even a sheetmetal intake. As for a cam, I'm thinking 24X/25X, maybe with LSK lobes. My goal with this is to make a lot of power, broad powerband, and have a strong, streetable motor capable of some pretty impressive N/A performance. More expensive, but more potential.

Which would you do? I'd probably spray on top of either one. All input is welcome.
Adam

Stang's Bane

iTrader: (22)

No replacement for displacement. L-92 heads with a sheet metal from mizfit. Hello 600+ rwhp.

8banger

iTrader: (16)

I'm leaning towards that. I think I might just keep it at a 421 though...not entirely comfortable with .060" overbore.

00Formula

If money is no object than i would go with the second choice bored .030. But if you were wanting to do more of a street/budget build than the ls2, stock stroke setup would be a good choice too just dont bore it .030 b/c the sleeves are too thin to increase the size that much. I think .005 oversize is what most do.

8banger

iTrader: (16)

On an LS2...you can do .030" safely. LS1's can't be bored much.

Beast96Z

iTrader: (21)

Depends on the money situation. Budget, go for 1, big bank hank, go for 2. 4.125 crank will cost you $2k right off the bat, however you could opt for a 4.100 Eagle and be in the $800 range.

SVT THIS

iTrader: (27)

I would go with option number one but with a little bit different route. I'd build it low compression and turbo ready, if not that way, go for number 2.

BIG BAD BLACKSS

iTrader: (4)

370 iron block, with a BIG hit of spray or alotta boooosssstttt!!!!

flippinz28

Iron block

KCS

iTrader: (20)

Well, depends what your gonna want outta your motor.

1.)Typically, an oversquare motor (bore>stroke) will make it's torque higher in the RPM range. More torque at a higher RPM will produce more horsepower as long as you have enough air (and a stable valvetrain $$$) to support it. It would probaby be better to use the LS7/L92 heads on this motor. Problem here is that you'll have to turn it higher, which you really don't wanna do on a street setup.

2.)No replacement for displacement. This will make power at lower RPM so exotic valvetrain isn't as necessary. Definately a better street car setup.