What H.P. gains from porting a modified 2v head?

Robert92867

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Supporter 2019
I had 1hotvega build me a modified 2v engine with drivability as the main performance goal. Upon inspection I noticed the 78 head had not been ported. With all the performance upgrades; 2V modifification, DUI, Scott Drake single outlet header, 2" exhaust, should I get the head ported before I install the engine?
Robert
'66 coupe. C4
 
The most gain is in the intake & exhaust bowls. There is only so much you can do on the intake ports, but more can be done on the exhaust ports.
I hope he did a 30 degree back cut on the intake valve.
I would bet 15HP increase.
 
wsa111":hhoaldvk said:
The most gain is in the intake & exhaust bowls. There is only so much you can do on the intake ports, but more can be done on the exhaust ports.
I hope he did a 30 degree back cut on the intake valve.
I would bet 15HP increase.

that sounds about right. the problem with the log head is the lack of proper flow through the head. porting can help though, but its hard to port the intake side since you cant remove the log to access the ports. the exhaust side can be ported, but for the street doest really add a lot for the effort required.
 
a look @ 'the Performance Handbook' or the above 'Tech Archive' can lend some info
 
Hi, I got a 1hotvega 2 barrel head on my Bronco. There is more power but to me the big noticable difference is now the engine breathes, revs up much quicker, and my foot is not always on the floor like it used to be. I cruise at 65 MPH at 2900 rpm. Good luck
 
Howdy Robert:

X2 on wsa111's estimate. To add detail, the porting on the intake bowls will be most noticeable at higher rpms. The back-cut on the intake valves will offer a flow increase from low rpms and on up.

Adios, David
 
Appreciate the info. Assuming I can get 1hotvega to remedy the porting issue,what would matching gaskets and smoothing casting flash add to the h.p. mix? If I have to pull the head and ship to Fresno for the work, do I need a fresh head gasket for re-installation? I might as well have him add a manifold vacuum port while he's at it for connecting to the DUI distributor.
 

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Hi, if you feel you have to have the port work done you can reuse the head gasket if the engine was never run.
Ford has a vacuum port lower on the log which probably has an Allen head plug in it.
I use ported vacuum off the carb for my distributor, but ask Bill what would work best for you. Good luck
 

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Re vacuum for the DUI... fordsix tech archives include dyno testing with a DUI. 1 pull made using ported vacuum and another with manifold vacuum. A 30 hp increase was reported using manifold vacuum. What would be the argument for using ported vacuum?
 

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As for port matching and smoothing the casting flash adding HP. It's all part of the puzzle, and if you did that alone and no bowl work, then it likely wouldn't add any measurable increases. Bowl work is where the majority of all port work gets the most benefit and gains. Adding larger valves without increasing the bowl size proportionally has little gains, but increasing the bowl size along with larger valves work to compliment each other and produces significant increases in HP and torque.
 
CNC-Dude":5rewh3go said:
As for port matching and smoothing the casting flash adding HP. It's all part of the puzzle, and if you did that alone and no bowl work, then it likely wouldn't add any measurable increases. Bowl work is where the majority of all port work gets the most benefit and gains. Adding larger valves without increasing the bowl size proportionally has little gains, but increasing the bowl size along with larger valves work to compliment each other and produces significant increases in HP and torque.
This (y)
 
Robert92867":2hsx1mcs said:
Re vacuum for the DUI... fordsix tech archives include dyno testing with a DUI. 1 pull made using ported vacuum and another with manifold vacuum. A 30 hp increase was reported using manifold vacuum. What would be the argument for using ported vacuum?
I would tap that now and plug it if you do no not use it, just make sure there is no bolt in that spot. ..What does Vega say ?
 
Those old dyno tests with a Dui are bogus, they compared their # to a stock DS11. As bad as the DUI is compared to a stock DS11 is no comparison.
The power difference between ported vacuum & manifold vacuum is BS, at WOT both are inactive.
I'll put my DS11's & my HEI recurved for your combo vs a one curve does it all is no contest.
Your choice. Spending $400.00 on a looser is what you did.
I like your attention to detail on your engine. Looks super.
 
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