-12 Brodix Heads

[CIGARETTEDFL]

Looking for someone to talk with who has real hands on experience with building an SBC engine with Brodix -12 heads using a carb induction.

[RCJ]

I've had 2 dirt late model engines with -12. Eric did one set for me 60/40 made 787 on a 400. Second set were ported when I got them 70/125 had the bigger intake valve.Made 798 on a 406. One had an old intake 15/18 (I think ) second I bought from brodix , intakes can be hard to find.

[perfconn]

Designed for alcohol not the best head for gas

[Birdlab]

What characteristics stand out as being best suited to alcohol? Plug location? Chamber shape? Cross section?

[perfconn]

Intake runner volume & plug location.

[Birdlab]

What accounts for the different plug location requirement for alky vs gas? Is it about avoiding preignition on alky by pulling the plug away from the hottest area of the chamber?

[Walter R. Malik]

What accounts for the different plug location requirement for alky vs gas? Is it about avoiding preignition on alky by pulling the plug away from the hottest area of the chamber?

From what I have experienced ... washing the plug tip down with the stream of the extra fuel with alcohol is definitely not a good thing.

[englertracing]

I've had 2 dirt late model engines with -12. Eric did one set for me 60/40 made 787 on a 400. Second set were ported when I got them 70/125 had the bigger intake valve.Made 798 on a 406. One had an old intake 15/18 (I think ) second I bought from brodix , intakes can be hard to find.

Just curious what rpm did they make that and what was the torque?

[Dave B]

We probably ran 2 dozen of those heads with intake manifolds on dirt late models.We ran both alky and gas.Gas made more upstairs power and alky more down low.It really comes down to what you do with valve job and cam specs on what worked.We never had a 410 under 825 hp with those heads.We averaged 840-860 with most of them. Intake manifolds took huge work to have enough area to feed heads .First heads we ever owned that would make 840 hp with 345 cfm as a min.Still a decent head but way better now.

[RCJ]

The -12 were the first head we ever got that didn't have a basic port shape. We had a home made flow bench and had ported a lot of stock heads. Our first try at them was disappointing. Had to take them to a professional to get the power out of them. It's been a few years back so I don't remember specific numbers but I also remember them making good power vs what they flowed. We always figured 2 to 2.1 hp per cfm of flow and they could beat that.

[levisnteeshirt]

I had a old set ,, 242 cc ,, the top of the intake port was close to the valve cover rail ,, some aren't that high. I've heard the better ones are like the set I had. I have to wonder since the port is shorter than a typical 18-13 degree head that it might have a peak HP advantage ? Why else would they still be in production? ,, I thought about checking on getting the ones I had rolled to a lower degree ,, I had Lee Severt from Dixie Performance near Atlanta Ga look at them for his opinion. He used to be local here and was up for a visit. We still talk. The only thing that stood out in his opinion was the long wall on the intake port could be made wider going into the bowl ,, but he liked what he saw ,,