vintage chromoly

iTrader: (3)

I just had a pair of brodix 2plus hand ported.
They are 312cc "as cast". After porting, probably closer to 320cc. The chambers came CNC finished and measure 124cc (just verified via "CC'ing" for CR calculations).
The heads flowed 396 on the intake and 330 on the exhaust. Pretty good I to E ratio.

The guy who ports all our stuff said he was impressed with the quality of the castings.

I'd seriously consider the AFR's if I was starting from scratch as you won't hear a bad word about them from most who have experience with them.

That said, I'd have ANY assembled head taken apart and set up right as most assembled offerings still need work. Also, cnc porting is great for a consistent "baseline" but will benefit from hand finishing.

*edit* heads are going on a 515ish (final displacement upon bore size) NA, 6000 rpm pleasure boat engine.

14 apache

iTrader: (1)

How much did these heads flow before the porting on this guys bench? And what was the lift for those flow numbers? That's some big numbers on the exhaust. My big dukes are only 15cfm more on the exhaust. Who did the heads?

vintage chromoly

iTrader: (3)

We didn't flow them before porting.
Pretty sure he opens them to .700.
I'll check the sheet when I see the machinist tomorrow.
Maybe I'm goofed up on the exhaust flow as that does seem high.
According to the brodix site they flow 340 and 240 "as cast".
A local old timer that's been at this for longer than I've been alive does my stuff. He used to do quite a bit of work for the local shops before CNC came around.

I'll report back as I certainly don't want to give bogus info.

*edit* 313 not 330 on the exhaust. Also, 2.30 intake valve instead of the 2.25 the heads come with.

stimleck

Lil Red I have been trying to thank you for the info on your friends Eclipse but your inbox is full, Thanks

stimleck

what about if he was sticking with the 502

stimleck

do these heads require machining or can they be used out of the box? Can you order a complete bolt on set?

Black Baja

iTrader: (2)

The general consensus today on cylinder head design has gone away from everything that we really looked at in the past as far as cylinder head selection for a engine package. The old practice was to get a head to flow as much cfm as possible and that's what everything was based off of to make horsepower. I've had conversations with more than one of the top guys and repeatedly been told that they told care how big the port is and cfm the head flows means nothing. When they design a custom head for a motor the do a velocity profile of the motor based on cubic inch and rpm (the engine is an air pump) based on that the use Computational Fluid Dynamics to do a 3-d model of the intake port and air speed simulations based on the layout of the port. Once the shape of the port is designed to have enough air speed to supply the engine they go in and tell the CNC what to do to the port so it has the correct shape for the air speed they are trying to achieve. This is what all the top guys are doing. If you spend $15000 on heads and an intake from Carl Foltz you don't get a sheet with any flow numbers on it. I begged and pleaded with another top guy to get some flow numbers on his heads he laughed at me and said they mean absolutely nothing and the only reason anyone uses them anymore is because they sell heads to the public. Whatever your left with after designing a port as far as cc/volume goes is what your left with. You can have a 300cc port that has the same velocity ass a 400cc port.

mike tkach

iTrader: (3)

i have been using dart heads for years but on a recent build i contacted bob madera for a cam and in our conversation he recomended a set of afr 315 cnc head for this build,so i gave them a try.when they showed up i opened the box and i was very happy with the heads.they look like man candy.the quality was as good,if not better than the dart,s and were quite a bit cheeper.i finished the build and went to the dyno,the engine made 60 more horse than i expected and the torque was huge.im not saying the afr head is best for every engine but for what we do,marine engines,im sold.

mike tkach

iTrader: (3)

steve,bob madera works directly with tony,the owner of afr,he can get you a cylinder head designed for your application and ready to bolt on.with bob,s knoledge and afr,s quality,even a dummy like me can make power.

vintage chromoly

iTrader: (3)

BB........how come cam grinders ask for the head flow numbers before they grind a custom cam?
Is it that to the average "sportsman" type enthusiast, the flow numbers are still relavant for sizing components and designing an engine combination?