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BigBlocksRule · 10-21-2011, 04:30 PM

The only 906's to avoid are the very first ones. After that, GM used smaller press-in seats that didn't hang so far out into the port.
Don't even try to redrill your intake to work, vortec ports are raised .100 and they're taller and narrower than conventional. Check sleazebay, you can generally get a good dual plane vortec intake for around $100.
Make sure you read about retainer to guide clearance issues, particularly if you're going with a cam with over .450 or so lift at the valve.
Great heads, spend a few minutes with a Dremel or die grinder working the ridge in the exhaust short turn. It's a sharp edge and doesn't take but a few minutes to blend it into the runner. Blend the seats into the ports as well.
DON'T TRY TO RESHAPE THE PORT, JUST BLEND THE CUTTER/MACHINING LINES!!!

10-21-2011, 04:30 PM	#8
BigBlocksRule Registered User Join Date: Jun 2008 Location: Lubbock, TX Posts: 2,047	Re: vortec heads The only 906's to avoid are the very first ones. After that, GM used smaller press-in seats that didn't hang so far out into the port. Don't even try to redrill your intake to work, vortec ports are raised .100 and they're taller and narrower than conventional. Check sleazebay, you can generally get a good dual plane vortec intake for around $100. Make sure you read about retainer to guide clearance issues, particularly if you're going with a cam with over .450 or so lift at the valve. Great heads, spend a few minutes with a Dremel or die grinder working the ridge in the exhaust short turn. It's a sharp edge and doesn't take but a few minutes to blend it into the runner. Blend the seats into the ports as well. DON'T TRY TO RESHAPE THE PORT, JUST BLEND THE CUTTER/MACHINING LINES!!!