I have been considering going with the Vortec head for a mild build. I figure that it is good performance for not much money, which is always a plus. In some of the research that I have done, it refers to the L31 Vortec head. If you search for Vortec heads, you find various casting numbers such as "906", etc. Is this the same thing?

Also, do the different casting numbers have different performance characteristics?

 

It might have something to do with cast iron versus aluminum Vortec heads

 

In a word, yes. L31 is the engine designation (ie L48, L82 & L88) ... an L31 is a 350 w/ iron vortec heads. 906 will bolt on a C3 with OE sbc ... but requires a vortec intake.

 

Chevy has a 180 runner size bowtie vortech head that has screw
in studs and the valve pockets cut deeper so more then 480
lift can be used if you wanted to in the future. the runner size is only 10cc bigger then the standard vortech head. The old 348 chevys and
early small blocks used pressed in studs, I can not see why in the
modern world why chevy would build a head with pressed in studs
like the 170 truck vortech head. The 180 bowtie head is probably a little
higher in cost. have fun

 

I looked into Vortecs once, here’s what I found.

The “906” is the last 3 digits of the casting number on the heads. The 2 most common stock Vortec castings are 060 and 906, I don’t know if there’s others. There’s a mag article on the net that claims the 060 as better, but there’s also web page from a GM dealer that says the runner, chambers and all, are the same. Who knows. Those heads are cast iron.

Vortecs have pluses and minuses. On the plus they flow real well in the mid lift range where most street cars need it and have a nice combustion chamber shape for good burn. They are also inexpensive.

Now for the minus on the STOCK vortec heads:

Intake - The intake is bolted with a much different pattern. 8 special bolts that go in at a much different angle. I’ve seen a little info on drilling and taping for our old intake pattern, but that casting is thin and its not recommended. Even so, the intake opening is also taller, which helps its flow, but old intakes don’t line up. You will need a vortec intake with vortec heads.

Hight – Not normally metioned, but the taller runner opening on the vortec intake can cause for a higher end height for the carb. It may or may not be a problem depends on your Vette and how much room you have to the hood.

Lift - The clearance between the valve spring retainer and the valve seal only allows for about .480 lift. This can be machined for more clearance and there are even tools you can buy to do it.

Springs - The stock valves are a bit wimpy and are not the same size as our 350’s. the choice is to have the spring seats and the stem machined for regular springs or get the beehive springs (beehives are expensive).

Studs – The vortec heads use pressed in studs. While they work in the truck application that they were developed for they are a week point in a vette motor. Unless you are going very mild, the studs should be pined or drilled, tapped, and replaced with screw in studs (studs seem most popular).

EGR – The vortec heads don’t have exhaust port n the middle used by some intakes for the EGR. Not a problem if you don’t have emissions testing, but if you do you might have to do an add-on EGR.

There’s also aftermarket Vortec type heads in both cast iron and aluminum. GM’s bow-tie iron head (mentioned above), the GM fast-burn aluminum, and the Edelbrock E-Tec 170 and 200s all come to mind. But they all cost more. One option is to by the heads that are already worked over. These solve some of the problems associated with vortec heads.

 

I already planned on getting a different intake for the Vortec heads, rather than try to modify the older style. I was looking at gettting either the new GMPP Vortec heads or a set of stock heads that have already been rebuilt. I have seen a lot of the high performance crate engines (400hp) with cast iron Vortec heads. Are they using the stock Vortec heads or some other Vortec heads?

Also, I have not seen many intakes with the heat opening for the choke.

 

You'll probably be happiest with a vortec intake, as planned.
You have not specified exactly which crate engine(s) ... but most are probably using either rebuilt/reworked GM vortec or aftermarket vortec. A pair of stock iron vortec (with springs to suit cam) easily capable of supporting 400hp.

 

I think the Blueprint and the Year One engine both use the Vortec heads. However, they have the 2.02/1.60 valves, rather than the 1.94/1.50, which I don't know if that makes a real big difference.

I have also seen, on eBay (so it may not be very reliable), a set of Vortec springs that you can just put right on and they are good up to .550 lift. They look just like regular springs. The prices is about $40.00.

 

They make a tool that you can slowly tap threads for rocker studs
on the engine, but what if the vortech head pulls a pressed in stud ?
what is your labor worth or mahine shop costs to fix it, cost for tools
or machine shop cost to cut deeper valve pockets if you should
decide to go with a higher lift cam, if you are buying new heads, thats
already done for a little more money on the bowtie head, and a 180
runner is not to big for even a mild 350 build. Pressed in studs are
1950s technolgy.

 

Where can I find information and price on the bowtie heads to compare them to the Vortecs?

 

I heard the 69 z28 springs would increase lift as well. DOnt hold me to that though

 

one place is sdpc2000.com. I think they will be higher in cost then the
170 truck head they also if I remember right use use the bigger valves.

 

They are quite a bit higher. They cost more than the standard Vortec, and they come bare. By the time you add all of the valves, springs, retainers, studs, etc., you're up to $800-$900.

 

I don't know if there is any truth to the matter about stock vortec heads cracking, but if you are wanting more than .480 lift camshaft you need to rework heads for springs. also suggest you look at

http://www.sdpc2000.com/catalog/2172...-Head-Kits.htm

 

I did see those head kits. They aren't a too bad of a deal. I was planning on using the Crane 272 Powermax which has a lift of .480, so I should be okay there. However, some sites say that the stock springs are good to .480 and some say .450. I don't know which to believe. I cannot find any lift numbers on GM Performance Parts homepage.

 

buy the standard vortech and tap them for screw in studs before
you install them, pressed in studs are a dependablity risk.