vortec heads

[chevy355]

I have a chance to get vortec heads for free off my bro's truck. Its a 1998 k2500 with a 350. I wanted to put the heads on a 70s 350. Will my intake work? Any modifacation id have to do? thanks

[nobull2]

you will have to change intakes and exhast manifolds

[spudz]

Originally Posted by nobull2

you will have to change intakes and exhast manifolds

Just intake, you dont need new manifolds..

[Mr. 250r]

Which vortec heads are they if I'm correct there's 2 of them the heavy duty trucks apparently had the lesser flowing heads of the two I can't remember the #s but a Google search would bring up a ton on them
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[RUSHNBOBO]

Some ¾- and 1-ton trucks came with Vortec heads equipped with a specially hardened exhaust seat that kills low- and mid-lift flow. Casting number 10239906 should be avoided. Look for casting number 12558062....

read this thread, it answers everything you need to know and more about Vortecs

http://67-72chevytrucks.com/vboard/s...d.php?t=485197

[chevy355]

Im not sure what the head numbers are, they are still in the truck

[RUSHNBOBO]

Originally Posted by chevy355

Im not sure what the head numbers are, they are still in the truck

If you can pop off one valve cover it's right here

[jojoman]

whta would the front of the vortec head look like pattern wise in front. you know how they got a design infront. cuz i really aint trying to open up the valve cover cuz i got this luck with gaskets that man let me tell you.

[RUSHNBOBO]

All early Vortec heads have part number 125508060. But these are made from two different castings 10239906 or 12558062. The difference between them is that the 906 uses hard seat inserts and the 062 uses induction hardening. Either makes a production L-31 truck head. The 906 is usually found on heavy duty trucks. Both "060" heads use 1.94/1.50 valves with a 165-170 cc intake port.

Exhaust bolts up intake does not .....production L31's need a 8 bolt style intake. Gm "bowtie vortecs" special parts dept heads, have a dual bolt pattern for intake 8 or 12

[jrcaprai]

Vortec Cylinder Heads: The Definitive Guide

http://www.nastyz28.com/forum/showthread.php?t=56505

[BigBlocksRule]

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!!!

[RUSHNBOBO]

Originally Posted by BigBlocksRule

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.

Use Crane Cam’s 10309-1 drop-in valve spring and retainer kit which is good for .550” lift with no machining.” about $160 bucks

[RUSHNBOBO]

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