Bowtie heads vs. Vortec heads
 

What is the difference between the bowtie heads and vortec heads?

Re: Bowtie heads vs. Vortec heads
 

Bowtie heads are racing heads. Most of the bowtie castings have large ports and are along the same lines as a set of dart iron eagles. The vortec heads are a stock head that came factory. They are the best flowing productions head from Gm but its not fair to compare vortecs to bowties its apples to oranges.

Re: Bowtie heads vs. Vortec heads
 

the vortecs out flow most bowtie heads,

Re: Bowtie heads vs. Vortec heads
 

There are also Bowtie Vortec heads. They are over the counter heads with larger intake ports, valves, etc. than the production heads.

Re: Bowtie heads vs. Vortec heads
 

vortecs might outflow bowties under .500 lift but anything over that and vortecs are done. They simply wont flow anymore.

Re: Bowtie heads vs. Vortec heads
 

These conversations are best had with specific part numbers in front of everyone :)

Re: Bowtie heads vs. Vortec heads
 

Utt ohh here comes tickers with facts again :lol: .... Very good point.

Re: Bowtie heads vs. Vortec heads
 

ok lets say the 906 casting to the 034 bowtie

Re: Bowtie heads vs. Vortec heads
 

This is a question that has an answer :)

The Vortec is a far better head. The 12480034 head is intended for racing classes that require a "Stock/Replacement" type head and they're based on the '462 (camel back) type casting...but with a ton of extra room in the casting for decking or angle milling and porting. They have a bit better chamber and runner configuration than the old heads, but not by much. They're only available bare for around $750/pair...so they're pretty pricey for mild street head!

This is the same type of head offered by Dart, World, etc. that has been certified for those "old skool" racing classes.

Racers add in 40 hours or so of porting and maybe a little angle milling and get a pretty decent tier 1 head out of them...but for most folks either the Vortec or another tier 1 head is going to be a better deal.

Re: Bowtie heads vs. Vortec heads
 

ok sweet thats some good info!

I was mainly asking what the difference between the two was. not really trying to compare. my bad!

So these "vortec bowtie" heads, are they good for the street or more for race?

Re: Bowtie heads vs. Vortec heads
 

No bad - just Chevy puts "bowtie" on a lot of stuff :)

GMPP sells Bowtie Vortecs in two sizes - "small port" 185cc under P/N 25534421 and "large port" 225cc under P/N 25534446. Both heads have 2.00/1.550 valves. It takes either a fair bit of RPM or a fair bit of CID to use these heads, so they'd be targeted at a 450+ HP 355 for the small ports, and a 500+ HP 400+ for the 225s.

Re: Bowtie heads vs. Vortec heads
 

so the small ports would'nt really go well with my 327?

it was just an idea more or less, i know that people have showed me some other heads but thought i might ask since i didnt know anything about them.

Re: Bowtie heads vs. Vortec heads
 

Well, this is a completely different question, i.e. what head to use for a specific application .

Specs on the 327 would help - CR, cam, intake, exhaust, gears, budget, etc.

Re: Bowtie heads vs. Vortec heads
 

well only i can't answer all of those questions.

im shooting for 9.5 to 10.5 cr, cam idk yet most likely a Crane around a .470 lift with a 110 lsa, exhaust not sure, gears 3.73, intake eldelbrock rpm air gap most likely, no more than 2500 stall , manual brakes. budget... lol probably $2500 but who knows

Re: Bowtie heads vs. Vortec heads
 

Small port vortecs will be fine with that cam.

Re: Bowtie heads vs. Vortec heads
 

In that case you're looking at the standard GMPP Vortecs - not the Bowtie versions.

Re: Bowtie heads vs. Vortec heads
 

I agree

The standard Vortecs will work just fine on a mild to moderate 327.

Re: Bowtie heads vs. Vortec heads
 

Fair enough. Thought i might ask though! Thanks guys!

Re: Bowtie heads vs. Vortec heads
 

Does anyone have some flow numbers any of these heads Also what is the best vortec head out there for street 400ci plus?

Re: Bowtie heads vs. Vortec heads
 

Most every aftermarket head manufacturer will have flow numbers on their website. Here are a couple private sites with some flow numbers also.....

http://users.erols.com/srweiss/tablehdc.htm

http://purplesagetradingpost.com/sum...fo/heads1.html

As for what head to use on a SB400, that depends on a lot of things. A couple being, how the rest of the engine is built and what is the intended useage of this engine.

Re: Bowtie heads vs. Vortec heads
 

That's a great site and the reference I use often :)

Vortecs: 230/148 @ ~.475
Bowtie/Small: 245/160 @ ~.500
Bowtie/Large: 260/165 @ ~.500

Note that although the flow isn't all that much higher on the small-port bowties, the intake/exhaust ratio is FAR better. You can also see that lifting these heads to the moon doesn't buy much.

Also note that all Vortec designs have far better low- and mid-range flow than even most tier II heads.

There are two aspects to head selection: flow and intake runner size.

First selection is flow, and that's based on the HP you want to achieve. The very general rule of thumb is HP = .257 * (intake flow) * 8 It's important to match the intake flow to the intake...a dual-plane manifold takes up about 25% of the intake flow, a tall single-plane maybe 10%.

Second is runner size, and the general rule of thumb is to use the smallest runner size that will deliver the required flow.

As you work these numbers you find out pretty quickly why the big dollar heads are worth every penny. :)