Vortec Head conversion question

[JVictor75]

Hello everyone,

On a basically stock 1971 350 small block with existing hydraulic flat tappet lifters, if I were going to convert to Vortec heads, what length pushrods should I use?

Same conditions, what rockers would I use? I would prefer rollers, with the idea of converting to a roller cam at a later date. Or would I have to buy all new pushrods after converting from the flat tappet hydraulic lifters to a roller cam anyway?

Engine is a "slightly warmed over" 350 4-bolt (I.E. slightly lumpier cam than stock, HEI, edelbrock performer intake, etc) and I am looking to use it as a fun weekend cruiser/Home Depot runner rather than some crazy-cammed, no-vacuum-having, rough-idling beast.

If you need block numbers, I can get them. I can also get numbers off of the heads.

Please help me out, all-knowing, all-seeing technical gurus!

This is one of the few things holding me back from getting the project truck running!

That and wiring........ ok and plumbing................................... and brakes........................ and................. OK, I've actually got a hell of a long way to go. But you get the idea!

Help a brother out!

[Gray Ghost]

Vortec heads create a whole new parts list for the conversion and from what I hear they don't offer that much of an increase in performance versus well built older heads. Why not rebuild the heads you have?

[67_C-30]

If you stay with the hyd flat tappet cam you won't need to buy pushrods (providing your's are in goodshape). You will self-aligning rocker arms, whether you go with stamped steel or rollers unless you get Vortecs with guide plates. The reason for the is that the holes that pushrods come through on the heads are much bigger on the Vortecs compared to the older heads. The rockers have pitched areas that keep it on the valve stem. The self aligning roller rockers basically have a washer on each side of the roller that does the same thing. They are quite bit more expensive than regular roller rockers.

[67_C-30]

Originally Posted by Gray Ghost

Vortec heads create a whole new parts list for the conversion and from what I hear they don't offer that much of an increase in performance versus well built older heads. Why not rebuild the heads you have?

You heard wrong...

[dadsbrew]

What brand vortec heads are you talking about? I have the GM performance vortec heads and 67_c30 is correct, you will need self aligning rockers which is no big deal. You will also need to buy a new intake manifold with the correct bolt pattern, vortec heads only have 4 bolts on each side and are straight up not angled. buy the correct gaskets and your golden, best thing I've done in a long time. For a set of 64cc / 194's gm performance cast iron vortec heads ready to bolt on out of the box the cost is only a little more than rebuilding a old set and they flow as much or more than a set of old 202 camel humps. Just my 2 cents

[67_C-30]

Originally Posted by dadsbrew

What brand vortec heads are you talking about? I have the GM performance vortec heads and 67_c30 is correct, you will need self aligning rockers which is no big deal. You will also need to buy a new intake manifold with the correct bolt pattern, vortec heads only have 4 bolts on each side and are straight up not angled. buy the correct gaskets and your golden, best thing I've done in a long time. For a set of 64cc / 194's gm performance cast iron vortec heads ready to bolt on out of the box the cost is only a little more than rebuilding a old set and they flow as much or more than a set of old 202 camel humps. Just my 2 cents

As the chart shows above, they flow more that any head on that list including the 462 double hump and aluminum Edelbrock Performer at .500" lift. I scanned this from a magazine in 2000. The ones in the test were used production truck heads. No performance anything.
I have more built engine than I can count and it takes a heavily massaged double hump (or any other production head) to outperform an out of the box stock Vortec. That's just flow characteristics, but the swirl-port fast burn style combustion chamber is way more effecient as well. Like you said, they are the best bang for the buck out there. They are capable for over 425HP out of the box with stock valve springs.

[Blackbird66]

I have vortec heads, and I am very impressed. They are limited on the amount of cam lift you can run out of the box, but many GMPP dealers sell these heads with optional valve spring set ups for more lift. The intake is different not only because of the bolt pattern, but the intake tracts are higher on a vortec. Self aligning roller rocker arms are like 25-50 dollars more depending on what brand you go with. Not what I would call a big price difference, especially when you consider how cheap stock vortec heads are.
I would go vortec again no doubt.

[Huck]

I have heard nothing but goodness on vortec conversions ---and if they are anything like the performance on the newer 5.3, it is truly outstanding. Now about how much will a converison cost me for an upgrade to a stock 010 cast 350??

[Blackbird66]

Heads are $270 each from Scoggin Dickey a GMPP dealer. These are stock and good for up to .450 lift. Add your choice of intake ( summit brand is least expensive GMPP ( made by edelbrok is most expensive) gaskets and rocker arms.