I'm getting ready to do a back to back dyno test with a 470 inch Mopar. I'll run the Trick Flow 240cc heads on the engine and then replace them with the 270 cc heads.

I do expect the torque peak to move up with the larger heads. I'm almost positive that the 470 inches pulls harder on the 240 cc heads than they can deliver. The question will be how does the engine respond to the back to back testing since I'll use the same headers, cam and carb. I should have the answer by the end of the month.

Me too. I think something like that is coming. In one of their short video 'extras', Dulcich said he would give DF a set of his max ported-relocated pushrod hole Eddy heads. Should be interesting.

Andy F, that'll be interesting!

Speaking in extremely general terms, this is a trend I have seen play out many many times.....

-motors built with nice flowing heads that would generally be thought of as "too small" for the application are often "over achievers".

-cars powered by motors with "bigger" heads seem to often be underachievers, and/or seem to be much fussier about things like cam selection, converter stall speed, rear gear....... Basically the whole combo is less forgiving.

Certainly there are many examples of the bigger heads doing just what they should, or even beating expectations....... But I've seen enough "big head" combos that were duds(of all brands) to know that just having big heads with big flow numbers does not guarantee big power or fast ET's.
At the same time, small heads with modest flow numbers often run way better than "conventional wisdom"(or many of the formulas) would suggest.

It's pretty easy to beat the 2hp/cfm(for an 8 cyl engine) yardstick when the heads are on the small side for the build, especially if the rest of the combo is well thought out.

Andy, since it sounds like TF did their testing of the 270 heads using their std port manifold, do you have any plans on trying that yourself?
I think it would be a good test, since you've already run it on the 240 heads, so that would be a back-to-back test where the only change was the heads.

I'm not planning on it but I might change my mind. I did a test fit with the TF intake and it isn't something that I'd recommend using on the 270 heads. It barely seals the intake gasket due to the size of the MW port. I could probably run it on the dyno but it just seems like it is asking for problems.

Ok so in a recent thread someone put up some molding pics of their ported eddy's vs trickflows and the trickflow was 2.243 square inches at the push rod pinch, which when pluged through various calculators and software, comes up as well and truly hitting sonic choke or excess fps rates at 5500 rpm on a 450" and roughly 500 rpm lower on a 500"

Whats going on there? On paper any B/RB motor that most pple are building (other than dead stock) needs victors or bigger port CSA? It just dosent match up with real world results that have been posted up here?

I'm assuming the peaks you're referring to are horsepower peaks, not tq peaks.

I had a 451 with 300cfm rpm heads making peak hp at 7200rpm, peak tq was in the 5500 range.

I trust the real world results more than I do the computer sims.

Yeah I agree, there is just too much going on for the simple models to provide good numbers. The rules of thumb are roughly correct, or they are correct for mild combos but if the engine is set up to really pull hard on the intake ports then you can make a lot of power with fairly small ports.

My 514 makes more than 900 hp with non-offset rocker arm EZ heads. So I don't even have the big EZ heads and I'm up over 900 hp. So that engine doesn't follow the rule of thumb on CSA or hp/cfm or things like that. If it was a normal bracket engine with unported intake, 12:1 compression, wet sump, etc. then it would probably follow the rule of thumb. There are lots of other examples of this floating around. Most any high end drag race engine violates the standard rule of thumb for example.

It will be an interesting comparison.
Usually too much attention is paid to port flow, and not much to port velocity. You want good velocity because that is what crams the air/fuel into the cylinder as the piston is moving up the cylinder before the intake valve closes.