Engine Masters Tests CNC-Ported Heads Against Vortec Heads On A 383 Chevy To See If The Performance Gain Is Worth The Cost!

[admin]

Ever been bench racing with some buddies and come up with a build plan? Does it usually sound like, “I’m gonna build a (insert engine here) and I’m gonna run this intake, these heads, and it’s going to make reality times three horsepower!” Yeah…I’m guilty, and a lot of you might be too. It’s like fishing in […]

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[SuperBuickGuy]

I agree with what they said, but I think they're utterly on crack when it comes to their rationale. The Vortec, iron head had more power and torque until 3100 rpm. That is the place most street engines live - thus, if you had those aluminum heads on your Corvette (and I had similar ones), you'd lose power and economy in your day-to-day life for marginal gain on a track. Funny thing about racing road courses around here... you're at full song for maybe 10 seconds of the 1m 30s lap. The issue is they compare a Vortec head that rules the street world and took it to the race world. My problem with their result is if you compared the result of that Vortec head with an AFR or Trick or pretty much any non-Chinese head the Vortec head would suck down low AND on top. Honestly, on the track the aluminum head would be useless - they don't even weight that much less then the iron head.

The comparison was bogus because, again, they're not comparing items designed for similar purpose....

[Beagle]

I agree with what they said, but I think they're utterly on crack when it comes to their rationale. The Vortec, iron head had more power and torque until 3100 rpm. That is the place most street engines live - thus, if you had those aluminum heads on your Corvette (and I had similar ones), you'd lose power and economy in your day-to-day life for marginal gain on a track. Funny thing about racing road courses around here... you're at full song for maybe 10 seconds of the 1m 30s lap. The issue is they compare a Vortec head that rules the street world and took it to the race world. My problem with their result is if you compared the result of that Vortec head with an AFR or Trick or pretty much any non-Chinese head the Vortec head would suck down low AND on top. Honestly, on the track the aluminum head would be useless - they don't even weight that much less then the iron head.

The comparison was bogus because, again, they're not comparing items designed for similar purpose....

Nobody in their right mind expects better gas mileage when replacing a 170cc intake port head with a 210cc intake port head with the same port length, especially when you're giving up compression ratio with the aluminum head instead of increasing it, which you should do as a matter of course with an aluminum head IMO. That is a pretty big port head from BluePrint - I'd honestly be looking at an AFR 195 on a street 383 or 350 in something heavier than a Vega. We all know big HP numbers sell parts, it is what it is.

I'm not sure I follow your rationale behind saying that losing weight AND and making more HP being useless... must by a typo!

[SuperBuickGuy]

The Vortec, iron head had more power and torque until 3100 rpm. That is the place most street engines live - thus, if you had those aluminum heads on your Corvette (and I had similar ones), you'd lose power and economy in your day-to-day life for marginal gain on a track

not sure how you're missing the point

The iron vortec head is better at low rpms and the AFR heads are better at high rpms. Quite simply the flow on a vortec head would become a choke point at rpms about 4500.... I have have some pretty cool flow-modeling done by my wife that demonstrates this....

[Beagle]

The Vortec, iron head had more power and torque until 3100 rpm. That is the place most street engines live - thus, if you had those aluminum heads on your Corvette (and I had similar ones), you'd lose power and economy in your day-to-day life for marginal gain on a track

not sure how you're missing the point

The iron vortec head is better at low rpms and the AFR heads are better at high rpms. Quite simply the flow on a vortec head would become a choke point at rpms about 4500.... I have have some pretty cool flow-modeling done by my wife that demonstrates this....

I'm not missing the point. I'm talking about the part that I bolded in your quote for clarity where you said " Honestly, on the track the aluminum head would be useless - they don't even weight that much less then the iron head."

I disagree. On the track, the aluminum heads in this test are going to have an advantage. Less weight, more power. I asked if you typo'd that for a reason because that statement is awkward.

In the type of car I would put aluminum heads on, I'm not going to be spending all that much time below 3100. That's what gears are for - keep it in it's happy place. If I was worried about economy, I wouldn't be putting a 210cc head on a 383. Hell, I'm questioning a 210cc head with less than 11:1 and a single plane in a light car with 4.56's and a 5 or 6 speed and frankly, I wouldn't consider a 2.08 valve for anything smaller than a 4.125 bore 400. I sure as hell wouldn't build a 383 with that much port for a 31" tire on a truck with a TH350 and 3.08's.

The test was valid enough in seeing what just a big aluminum head would do on it's own to an existing shortblock. Is it the engine you would build? Obviously not... but lots of guys want to upgrade one step at a time, so the test is realistic, just not ideal.

[Beagle]

I read your other post and I'm wondering what you are referring to with "aluminum vortec" ... the Blueprint chamber doesn't look like the Vortec casting to me.



lots of shadows, here is a better shot of a "Vortec" truck casting:


chambers are pretty significantly different.