Vortec 906 heads

[dirtplay18]

Wondering what year engines these were on?

[SLM98]

Was the L31 option on chevy pickups in 1996

[dirtplay18]

How do they stack up against the old gm double humps?

[SLM98]

Combustion chamber alone is worth 10-15 over hump heads

[dirtplay18]

Direct bolt-on to an older 350 block? Thanks for the info!

[speedbuggy]

Direct bolt-on to an older 350 block? Thanks for the info!

Direct bolt on to block, but intake manifold bolt pattern is different. You will need a Vortec-specific manifold. If your class requires cast iron intake, this is going to be the tough part 'cus there were no stock iron GM manifolds for Vortec-equipped engines.

Only cast iron Vortec intakes that I'm aware of are the Mercruiser marine intakes. Those were available in 2bbl and 4bbl. It will be up to your tech inspector as to whether you can use them or not.

I have heard of people re-drilling regular Chevy intakes to fit the Vortec bolt pattern, but don't know how successful that has been. There may be a good reason for it, but I've never heard of anyone re-drilling a Vortec head to accept the old-style intakes. If there isn't a physical reason why you can't do this, it might be a better option.

[SLM98]

I have drilled & tapped for old style intake intake and worked out fine. Need to do a little port matching on the port opening of the head. I think EQ has a vortec clone with the old style on them if you can use them.

[dirtplay18]

Appreciate the onfo fellas!

[Krooser]

BHJ makes a fixture that allows a machinist to accurately drill the old intake pattern in the Vortec heads. Find an engine shop that has one and it's a simple deal.

[nguyenvinh2]

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