[grandam1979]

Originally Posted by steve25

I must be honest by saying that I am not impressed!

Here’s a dyno test of a 364 cid SBC with Trickflow heads that I ported up to 260 cfm.
The motor had 10.25 compression and a Crower cam.

Two flat tappet hydro cams where tested .
The final cam as used in this test made 9 more ft lbs of torque and 17 more hp.
The cam specs where 220/226
Cam Lift .462” .470”
1.6 rockers where used and the cam was advanced from 112 to 109.
A 700 Holley was used on top a Victor jr manifold that I had blended the plenum on and gasket matched,

He put a engine together with out of the box parts compared to your hand ported heads and intake and made 17 less hp I think he did pretty good and with some fine tuning could have beat the numbers you came up with. They never even changed timing that could have been the difference right there. JM2¢

[Steve C.]

"I thought we decided comparing results from different dynos was “iffy” at best. Maybe I misunderstood."
Murf

In addition to the potential different results from different engine dynos, how about comparing actual engine dyno results from a computer simulation program.

Example, I know on the Performance Trends Engine Analyzer v3.2 program on the input you can use either "Standard" or "SAE" Dyno settings for the running conditions/weather. If using the Standard setting it will give you much higher numbers. Using a Performance Trends program I also found the results can suggest peak power at a higher rpm than the actual engine dyno results. Actual intake manifold runner lengths and runner volumes for input are necessary, no guesses. Same with cylinder head flow with input at the proper valve lift as required in the instructions. And actual carb cfm, not what they might be rated at. Etc, etc. NO GUESSES ! You need to know the specs of your engine combination for accurate results.

Now the question are the results from a computer or did the OP have the engine tested on a actual engine dyno.




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[PontiacJim1959]

Originally Posted by Steve C.

"I thought we decided comparing results from different dynos was “iffy” at best. Maybe I misunderstood."
Murf

In addition to the potential different results from different engine dynos, how about comparing actual engine dyno results from a computer simulation program.

Example, I know on the Performance Trends Engine Analyzer v3.2 program on the input you can use either "Standard" or "SAE" Dyno settings for the running conditions/weather. If using the Standard setting it will give you much higher numbers. Using a Performance Trends program I also found the results can suggest peak power at a higher rpm than the actual engine dyno results. Actual intake manifold runner lengths and runner volumes for input are necessary, no guesses. Same with cylinder head flow with input at the proper valve lift as required in the instructions. And actual carb cfm, not what they might be rated at. Etc, etc. NO GUESSES ! You need to know the specs of your engine combination for accurate results.

Now the question are the results from a computer or did the OP have the engine tested on a actual engine dyno.




.

I think comparing dyno results from one engine to another is simply bragging rights and meaningless - especially when comparing one manufacturer engine to another.

Are all dyno's identical enough to provide exacting results if I were to span the country spot testing an assortment of dyno's with the same engine? Does each dyno operator use the exact same procedures as the "other" guy. Are altitude, outside temperatures, and humidity always taken into consideration and each dyno session hermetically controlled to have the exact same room temp, air pressure, and humidity percentage?

So dyno number comparisons are meaningless from one dyno to the other, but may be meaningful to the specific engine being dyno'd on that specific dyno with any/all adjustments being made to that engine while being dyno'd, or being dyno'd after any parts adjustments, changes, or modifications. Otherwise, comparing dyno spec sheets from one dyno to another, one engine to another, or one location in the country to another is meaningless.

Dyno results can also be meaningless in that the tune can be completely different once installed in the actual car - where the rubber meets the road. So all that was fine tuned on the dyno to get those stellar bragging numbers no longer applies.

It is real easy to dissect one guy's build and then throw out what he should have or could have done as if he made a mistake.......or is an idiot - this or that head, this or that cam, this or that intake, this or that carb. If I use iron heads and provide my dyno numbers, don't insult me and say I should have used KRE heads and that would have really woken up the engine. Why not simply suggest a 6-71 blower while at it because that would really wake up the engine as well. For some, it is budget, for others it may be a step in getting to the bigger build, and for others, maybe that is all they were looking for from there build/car. Not EVERYONE needs or wants that easy magic "500HP" that is so frivolously thrown about here. I can't believe how I was ever satisfied with the tire smoking results of the factory provided 400CI in any of the GTO's and Pontiacs I have owned. What was I thinking?

Many of these posts always seem to go sour and turn into a peeing contest and not focused on the OP's original post. Why?

Don't give me the "well that's how we do it here," or "you need to not be so sensitive," or " if you don't like it find another forum" response. I can handle all this crap just fine and some of my posts are deleted for throwing comments back that are considered too harsh or insulting. Yet, some of these posts, although not directly attacking, are an insult, rather than support, guidance, or suggestion. Know when to add a worthy comment and know when to zip it up.

I have a set of Speedmaster heads and I think the point of this post was about those heads, on the OP's engine, and their results, ie, another engine build we can use as reference - I'm interested in that, and that alone, not what other heads or cam or intake I should have used, and not what other dyno sheets reveal.

[scott70]

I think these power numbers are pretty good,,,should move your car very nicely!! My 455 with iron heads dynoed best at 32 degrees.Tried 30 and 34. What do these speedmaster heads flow out of the box?

[GoatZillaRacing]

Originally Posted by scott70

I think these power numbers are pretty good,,,should move your car very nicely!! My 455 with iron heads dynoed best at 32 degrees.Tried 30 and 34. What do these speedmaster heads flow out of the box?

https://www.facebook.com/PontiacSpee...84014848693438

Prices have gone up but flow numbers are the same.

[PontiacJim1959]

steve25
"It's not so much the seats and there press fit into the ,its how hard the Aluminum as a whole has been tempered which aids in supporting the seats above a certain amount of spring seat pressure."

"In regards to all heads made off shore , I think they are all made with powered metal seats, and if so this is a short coming I would want to know about!"

PJ - Where do you come up with this crap? How do feel about conspiracy theories?

How many Speedmaster heads have you purchased and tested in your laboratory in securing such results? I wanna see da facts. Arghhhh.