I've been debating whether to have a used set of 906's redone or to just sell them and buy a set of bargain priced Ebay heads. If you add the price of a valve job with what I can sell the heads for you can just buy a new set of aluminum heads and not worry about coil binding?? I'm building a 383, I received a 1 pc crank instead of a 2pc and had to end up buying a vortec engine for the block. I only paid $100 so I might come out on this deal for a change but the wife won't ever believe it. Ha! Any thoughts or recomendations? Not really wanting to build a racer but wanting to bring back some of my old pontiac torque memories.

 

Anything but procomps. Dart Iron Eagles are about the same price.

 

Mako is right. stick with good heads. I bought the Dart shp aluminium heads and they are built really well. I should know how they perform this weekend as I'm getting ready to fire it up.

 

Vortec over procomp. Dart ago looks like good head.

 

 

You'll have a lot less getting the Vortecs right than the ProComps...regardless of what the ad says, they're nowhere close to being ready to bold on out of the box.

 

I'm not really getting the math here

A good refurb of a set of Vortecs should run no more than $450 with guides, etc. You're combining the cost of that valve job with the $200 or so you could sell them for to get a total of $650 that you could spend on "better" heads and be "ahead" financially?

If your power targets are modest, Vortecs are fine and a great deal - the shop can easily cut the guide bosses when they do the guides, probably for < $50. I'm not a big fan of increasing lift on the Vortecs as they don't increase in flow much past .460 or so...but if they're getting overhauled it makes sense.

The Vortec block is a great foundation, especially if you got the shortblock with the lifters, retainers, etc. as it makes for a really cheap roller-cam shortblock.

ProComps are junk - I've torn down a few new heads to look them over and sent them back. They hog out the ports to make big flow numbers at high lifts...but the quality is "eh" and you don't want to be fooled by the flow numbers. I think I posted a flow spreadsheet around here somewhere with a comparison based on reasonably valid numbers and they told the tale pretty well.

 

Look for a set of GM Fastburn aluminum heads.
I picked up a new bare set for $500 on ebay.
That way I put in the springs in that match my cam.
There are better deals out there than Procomp.
Same goes for their manifolds - I sent one of their manifolds back to a speed shop supplier on ebay because the quality was SO POOR. The walls between the runners were not square. Just sloppy all the way around. Ended up getting stuck for the return postage but still better off with the Edelbrock Air Gap I found used on ebay.

Procomp = China = crap.

I know - I work for a chinese pottery company. Constant battle to get them to understand "American" quality.

Good luck
Bman

 

For about $150 more you could have had a NEW set of COMPLETE Vortecs...that outflow the "Fastburn" heads by 20-30 CFM

 

Would it reasonable to think that one could port the vortecs some for better flow? super chevy did a comparison on sbc heads, with procomps involved and although they made more power than 882's, they were in no way close to other aluminum heads.

 

There is an article about small block heads in the new Car Craft. I think there are 8 brands, all under $1,000.

 

I've been researching new heads for my street driven Vette. The Vortechs seem to be the best bang for the buck. Unless your getting crazy with the cam as far as lift and duration go with the Vortechs. I was lured to the aluminum Procomps also. I read a lot of posts here by knowledgable engine builders and such. I'll put my money on GM instead of China.

 

There is a bit more flow in the Vortecs by working on the short radius and cleaning up under the bowls a bit...but not much, and unless someone's going to do it themselves (and knows what they're doing...one slip of the grinder and...well...) it's not really cost-effective for the improvement vs. the investment.

Keep in mind that the flow - especially the mid-range flow - on the Vortecs out of the box are better than many first-tier heads!

I think the 882 port was done by Chevy High Performance, probably the single worst car ragazine on the planet. The writers aren't car guys and don't touch a wrench...they just go to shops. Porting a set of 882's is a HORRIBLE investment.

 

Why do you have to go new? If you don't want to redo your vortecs, just buy a used set of Dart SR torquers or Dart sportman heads. They're cast but make great HP. I used a set of ported torquers on a 406 and it screamed, about 450hp. It was my first port job on a set of heads and it worked great.

Rob

 

But are we talking aluminum here?
Wouldn't that be better re: high compression and detonation?

 

Well, that will open a can of worms for sure So this is just one guy's opinion.

Two aspects to compression - first, the amount of power built from more compression is a few percentage points, and of course we're limited on the street to around 10.2 or so on a premium fuel, carburated engine. If you can get up around 9.5-10 for premium gas, you're good.

Second, as for aluminum heads allowing higher compression and being less detonation sensitive, I don't buy it. Car Craft did a great test a few years back and on the dyno with identical heads on the same shortblock, they didn't see it. Aluminum heads weigh less, and they are far, far easier to cast and machine.

But specific to "Fastburn" heads, the huge difference in flow vs. iron Vortecs means it doesn't matter - the Vortecs just blow away pretty much every tier 1 head.

 

Interesting info but my understanding is that quicker heat dispersion in aluminum heads is what helps the prevention of detonation which we know occurs after ignition in the cylinder.
Sounds like I need to do more research.

Thanks

Bman

 

Besides........."Fastburn" just sounds so much cooler than "Vortec".

 

At a streetable (premium pump gas) compression ratio ( < 10.5) with the appropriate quench (~.040) no GEN I SBC should have trouble with 34-36 degrees of advance with iron heads.

Quench has far more to do with detonation sensitivity than the material of the cylinder heads - and is commonly ignored by many engine builders.

Engineering and thermodynamic theory for racing engines is a different matter and outside of my experience.

 

You know what they say about opinions, everybody has one.

I do not agree with this statement. You, by your own admission build primarily moderate performance street engines. You can get away with less cam with the same compression without detonation issues with aluminum heads. This comes directly from my personal experiences. I have changed out heads on a build from Iron to aluminum for just this reason. When you get over 10 to 1 the ability to use a smaller more streetable cam makes a big difference. Rule of thumb if everything is set up right 8 to 1 DCR on premium with iron heads. 8.5 to 1 DCR with aluminum. I alway err on the side of caution and go .2 less to be safe.

http://www.carcraft.com/techarticles...t/viewall.html
Here is the car craft article you referenced. They are running a cam that has a duration of 260 @ .050. No detonation issues with iron or aluminum. I don't doubt that.
I ran the numbers.
Compression 10.884 to 1.
DCR 7.689 to 1.
Quench .046
I see why there are no detonation issues running 91 octane. You can run 13 to 1 on pump gas with a big enough cam. It is just going to suck trying to drive it on the street.

Proper quench should be a priority on any performance build.

That statement is totally misleading and untrue. Any base 180 cc dart, brodix or AFR head will outflow vortecs. If your looking at a tier 1 head from any of these manufacturers with a 195 - 200 cc port (which is proper sizing for a 383-406) they will blow away a vortec on intake flow, exhaust flow and lift capacity. Vortec heads do have their place. They are a good option on a warmed over 350 on a budget. They have too small of ports and limited lift for a 383 unless your looking at a lower rpm, high torque engine, They came on truck engines for a reason. 170 CC ports are a restriction on any 383 with over 400 hp and a redline over 5500. You might get more hp than that or more rpm but a bigger port will get you more, easier without giving up anything at the bottom end or in streetability. Too big of ports is a drawback as well. Over 200 CC you will lose some bottom end power but pick it up up top.






This is just one guy's opinion.