cnc d heads
 

What do you lose by not having cnc'd heads? What are the benefits? Power? Torque?

50 horsepower. But that's kinda a loaded question.

What's the application ? what's your goal ?

i would say 50 hp with both maybe, 25 hp each if you are running a twin set up. i wouldn't worry to much about that dale unless you are planning on making big hp (above 700 hp). it never hurts, just depends on what you want to spend and what you are trying to accomplish. are you thinking about porting the heads you already have ?

If your only getting 25 hp out of your cnc porting time to find a better head porter!

Depends on what you're comparing the CNC's head to..

540's 700hp dart heads

How much do you think you are going to gain by porting a set of heads? Have you ever had a set done and how much did you pick up on the Dyno, not just what your head guy told you you're gonna make. Btw, not much need to port a set of heads unless you are running blower motors

I would think that a blower engine would be less sensative to the head port as opposed to a NA engine due to the fact that the blower pushes the air in.
I always thought that a NA engine benefitted from optimizing the cylinder heads more than boosted engines.

Actually they both respond equally to the port. Blowers don't push air they compress air. The cylinder head needs to be based off the cubic inch and intended max rpm if it has a blower or not doesn't matter. A blower will help with a poorly combined head/cubic inch/rpm combination but will still benefit more from proper head sizing.

From Bob M on my 540 build that I am looking at AFR325's through him.....cams and valvetrain also..

"spend the extra 175.00 on CNC combustion chamber porting while buying the heads now, full port not needed in your application at 700hp" he said on a combustion chamber CNC cleanup is 80% of the gains over a full CNC job, now we did not discuss gains in actual HP over not doing it, but I know that since I am buying heads and they will be new, I am gonna spend that 175 per set, lets say it is only 25HP, thats a very good return for 175.00 in my thought process....700.00 more for full portthat is not needed in my application he said is not worth that 20% Again, that is MY application and Dales goals are nearly Identical to mine.

Yes I have. Porting heads makes a huge difference, My first set was in the early nineties David Reher did a set of GM w port heads for a 496cu in top sportsman engine. holley tunnel with twin dominators, it made just shy of 1100 hp. not only did they cnc port the heads and combustion chambers but they also cnc matched the pistons. My latest ones were 2 sets done by Curtis Boggs, they were done from a program designed by Island Racing. The castings they used were Brodix -2plus mainly because these had enough material so they could get the design they wanted. These are 565 cu in. 9.3 comp., efi's. Tim Hogan made us a set of sheetmetal intakes and we use hardin cyclone headers. They made just over 750 hp fully dressed running wet exhaust. more important is the nice long flat torque curve, at 3500 rpm they are making 560 ft lbs. with a peak at 5300 at 685 ft lbs, and at 6400 where they make peak hp they still make 620 ft lbs. So yes cnc porting is well worth the effort if you take the time to plan the whole engine. We spent 3 months working with Tim to get the intake runners and plenum design right so we could acheave the torque curve we were looking for.

Single 4 on the 565's

No a merc 525 mono blade that was cnc much larger not sure of the cfm of it though.

Oh sorry didn't catch the efi. Even though I read it twice.

CNC in of itself means nothing power wise.

It's all dependend of what your motor wants, what it's getting now and what that head with whomever's port that's been copied into the cnc programming, will get you.

Since this thread started with a very generic question, I'll go to an extreme.

Buy a set of Edelbrock Pro Ports, finish the comb chamber and valve seats so you can put valves and valvetrain on it and go run it. It will be a turd cause everything is air orifice is puny, leaving as much metal as possible so the head porter can make port out his own runner design within reasons.

So, say on a 540 10:1 motor this could be worth several hundred horsepower or more.

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Anybody here could 'port' a set of heads and send them in to be digitalized and thus have a cnc machine for heads recreate those in other same heads whenevr you want.

Chances are, most of us won't want them.

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Many of Brodix's heads are not that great out of the box. Why ? Same concept as 'Pro Ports' Because they realize most will go to a head porter before it get's put on an engine. Thus, these heads will concentrate on leaving more material for the porter to be able to do more of what they want to do .

Furthermore, thus why Brodix get's more 'bad mouthed' by the bolt on and go crowd, vs the very serious crowd.

You need to call a cylinder head porter tell him the castings you have and see if you will benefit from the work. Call more than one porter.
My NA engines make 960hp@6700 with no superchargers. 900hp@ 5800 840lbs@5200

I am a die hard Brodix guy they make big power out of the box. Stronger rocker bosses. The dart rocker bosses are not that nice.

On the pro 1's yes they aren't the best. But the Race Series is a different story. Did you make 960 with Head Hunters? If I had the money Id give the SR20's a shot I bet it would be a killer head on a NA marine engine. I bet they would go 1050 on pump gas.

X 2 on the Brodix

This is the 4th time I am changing the heads on my boat have some good dyno time. The sr20 the port volume is to big the low end and mid range would be gone or I would of bought them but ended up going with the big duke sweet 16*.
BB2+ boat plenty of power to plane off than I went to a 351 oval port boat would plane off ok. Put the 383HH on it would not plane off on calm water. But the power went up may be 40 or so. Think sr20 is 440cc and the big dukes is 415 but the runner is longer.
Shooting for 1050-1075 but it will be on 100LL aviation gas.

http://www.raceflowdevelopment.com/R...odix-bb2-4.htm http://www.raceflowdevelopment.com/R...s-24-bbcRR.htm

Worked on a set of the 18* race low port heads had to weld the tops of the ports up to keep the exhaust from leaking out. Hold the gasket on the head and you could see light above it. Don't know how they sold this.

I'm talking typical Brodix's guys. It's all generic talk. Brodix get's a low rap a lot....and it's just from the bolt on and go crowd. No head hunter stuff, no cnc stuff......

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http://www.raceflowdevelopment.com/R...victor-pro.htm

:drink:

The only way I would not buy CNC heads if they where not going on my motor!:drink:

Curtis is very good!

I don't know the man just thought his products looked impressive.

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If you can afford him Tommy Slawko does some amazing heads. But you have to pay for it.

What did those run u?

That's awesome. What size engine are these on? Exhaust?

600" 1.860 valves Large tube headers. Not sure of the final power but should go over a thousand. I will post some more pictures.

We prefer pictures of nude models displaying high performance boat and body parts.

Man thats a bad ass rig. Huge NA power in a straight bottom thats faster than lots of stepped and supercharged boats. Good job.

Awesome stuff man. What kind of lifespan are you getting out of the engines/valvetrain at that level?

Not sure of the hours I have put on them. Valve train on old motors had 2.4 stainless valves it would tare up the intake lift ramps on camshaft. New builds are getting Titanium intake valves that have the Crn coating so camshaft will live and going with the .937 lifters and 55MM camshaft. My biggest problem is if you have a leaky header and don't know about it ****s stuff up.

Thanks it runs pretty bad azz for a old v-bottom with no steps.

We're you using a standard base circle cam on the old build?

Yes the upgrade I am doing is going to fix all problems. I would of run a stainless intake valve but the weight is a killer on that size valve. 2.450 6.700 long.
What kind of valve springs you running and how much lift?

Pac springs I think 260 closed 650 open .750+ lift 55mm cam .937 lifter we are going to spin 6500rpm with a 632.

I think Titanium intake is the way to go. Springs will last longer, guides, lifters ect. Ect. The motor will rev a lot faster I'm just guessing at this number but I bet you save around 3lbs going to a titanium valve. That's what I would use with my new setup if I had the xtra money. I still may we will see.