350 or 400 turbo

[jay97lt1]

I will be converting my m6 car to a auto. I have a 350 and 400 Turbo. I know the 400 is tougher but takes more to turn it. Engine is a 383 12:1 compression, ported 643 heads custom grind cam on a 250 shot. 28 inch tire 373 or 4:11 gears. It will be mainly a street car.

[Camaro96]

I would do the 400. If your doing mainly a street car to drive. I would get in touch with Cahall. You may want to look into a 4L60E for overdrive and improved street manners.

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[jay97lt1]

I have a 350 and 400 already both in great working shape.

[Injuneer]

Street car.... 4.11 gears.... no O/D. Not too street friendly, unless you avoid freeway driving. With street tires, I was turning almost 4,000 RPM at 70 MPH. It is a non-locking converter, which didn't help. Didn't take long before I opted for a Gear Vendors O/D. With the torque available from the 250-shot go with the 400.

[myltwon]

Th400 damn near unbreakable when built right, the th350 isn't really a huge step up in strength from a 4L60e and might even seem stronger just because so few people know how to properly build a 4L60e.

[jay97lt1]

Its going to be a weekend car mostly to shows and to the track.

[firebird_1995]

Will you be running 1/8 or 1/4 mile? What is the max rpm you want to spin the engine? You may consider a higher gear, maybe a 3.50 ratio. It would help with the highway rpm as well as cross the beams at a more reasonable rpm

[theset3]

What are you doing with the M6?

[SexyTransAm]

another vote for 400, seems u should be making good power and tq

[jay97lt1]

Selling it.

[zooguy]

go th400