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What is a price range to expect from a good machine shop to CNC port heads?

2K views 7 replies 6 participants last post by  PGG 
#1 ·
Wondering average cost to CNC port heads to maximize their flow? Will most machine shops be able to offer this or will it need to be a specialized shop? Any suggested machine shops for Mopars in North Texas?

Thanks PG
 
#2 ·
CNC, is a form of computer controlled machining, normally used to make new parts. To use it to port a head, they would have to 3d scan the existing heads, then on the computer. map out what needs to be cut. I would bet the only place you will find such a service, is a nation wide speed shop. And then, it might be only for the high volume engines, like a chebby small block.

The only advantage a CNC job would have, is they could set it up once, and then let the mill do many heads, all the same. To do one set of heads, I would imagine it would be super expensive. Likely several hundred dollars just to have the computer operator scan, and set up the program.

Porting and polishing heads, and intakes, is amung the simplest modifications to do to an engine, and can be done by yourself quite easily. I would not spend the money to have a shop do it.

CNC, is one of those fancy buzz words, like billet, Sounds high tech, but in the end, means very little to the end user/ consumer.

 
#3 ·
Yep.
You'd be better off buying a set of aluminum heads from Indy/ Trick Flow/ Edelbrock/ 440 Source.
They've already done the homework plus you'll save quite a bit of weight.
Not to mention you can get them closed chambered. Way better than the open chambers on the iron heads.
I listed them in order of my preference if I were to get another set.
 
#4 ·
#5 ·
DODGEBOYS said:
Good job there!
My son and I did this for the 440 he put in his Dart Sport back in '01.
Pretty simple with the guides. Very messy with the metal flying everywhere. ;D
 
#6 ·
yes cnc Computerized Numerical Controll  a production ( many many made = production) method of replacing an expensive skilled machiest with a parts changer ....  2 choices : a shop with the machinest AND a flow bench , a shop with the machinest and he uses "known" techniques with out a flow bench . Really what your paying for is HIS name/reputation ... its WAS an  artform as much / more than a skill so price varies widely ... PAY for his art as fast as you wanna go ...

DIY carefull use of a dremmel , performance gaskets as guides , and reading up on "known" methods , then a quality valve job at a shop can be just as good ... and more "fun" ... polish the exhausts best , leave the intake runners a little rougher ..  know that this work is worth hundreths MAYBE  tenths of seconds at the drag strip in better flow/ higher rpms , so make sure you valve train stuff is up for the rpms to gain any marked benefit .
 
#7 ·
An interesting note,The mopar performance template is set up for 1.97 intakes and 1.625 exhaust.Its interesting because the intake is already oversized in factory form compared to the piston bore size and exhaust valve size.According to theory with our engine's geometry they heavily favor the exhaust side because of the long rods so the "ideal" exhaust valve size for our mopars with a 1.92 intake is actually a 1.70.Its the reason why magnum heads out of the box respond better to exhaust porting than they do to intake porting.Longer rods lack intake vaccum,but have more complete combustion for the air/fuel they do manage to suck in.
 
#8 ·
Ok I was asking because I was offered a deal on a set of Edebrock aluminum small block heads.
I was thinking of grabbing them for future use and thought it might be worthwhile to CNC them since the better thought of brands are CNC ported. Great information everyone I appreciate it. PG
 
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