[firechicken]

Big cam difference there though...

[Murf]

Originally Posted by steve25

I am not putting him down, nor am I a hater by any means, and I am sure as Hell not jealous, so stop your second guessing as to my nature or my intentions please!



He certainly was kind enough to post his dyno results with these heads used and by doing such was asking for a opinion, which I gave, and I fact I gave the SBC build as a reference for my opinion and the info from the Edelbrock ad, so I gave 2 examples, and not just opinion!



If you do not want opinions then don’t do posts asking for such!





The simple fact is that his 400 build would be making more power if he was running the KRE or Edelbrock D port heads on his 400!



Anyone care to comment as to why?



All this just goes to show how the combos we build need to be crafted more carefully and that’s because I know our Pontiac motors can equal the power of this SBC build I posted info about.



Here’s a great old example from the 1991 in terms of a 400 build with ported iron D port heads that certainly where not flowing what those out of the box Speedmaster heads are.



Anyone recall this 475 hp build that Pete McCarhy did ?

Hi Steve, Would you have any idea what compression he was running with that 406? I see it has a lot more cam, I was wondering if the C.R. Might be more than 10.5 to 1.

Thanks
Murf


Sent from my iPhone using Tapatalk Pro

[Cliff R]

I take a stab as to "why".

Right to start with it has a "small" cam in it on a tight LSA. That's going to pull the power down some in the RPM and not take full advantage of the improved cross section and port flow of the aluminum heads.

With only 10 degrees more seat timing and even if it was left on a 110 LSA with early intake closing it would have picked up at least 10 more HP.....IMHO.

A 400 isn't a huge engine but if you want to make good power from one you need to squeeze it hard and put some cam in it. Good flowing heads bolted to a 406 CID shortblock all by themselves don't guarantee big power.

As mentioned in my first response, it did good for the combination of parts. A 400 with KRE heads with a Crower 60243 cam with high ratio rockers will make closer to 450-460hp and 465-470 or so torque.

https://www.crower.com/searchresults...0243&x=13&y=10

As far as comparing Pontiac engines to an SBC or anything else it boils right down to CID, compression ratio, head flow and cam specs. We need to keep in mind here that all of these V-8 engines are nothing more than 8 round pistons moving up and down in 8 round holes. Some folks will argue bore/stroke, rod length, spinning and reciprocating weight, etc, but at the end of the day in the RPM range we're running these engines the power produced is going to directly related to the first things mentioned, not the second.

So CID, compression ratio, head flow and cam specs are the main players here. Intakes, carbs, exhaust systems are minor players and we can mess with those items to find out what any particular combination likes but you aren't going to see BIG improvements messing with those sort of things, assuming everything being tested is pretty well chosen for the engine combination right to start with.....FWIW......Cliff

[Half-Inch Stud]

Originally Posted by Skip Fix

On my RAIV headed 400 the T1, T2 and HO intake all dynoed within 1 HP but at the track the T1 using the same Q jet picked up 1 mph so was making HP but lost .2-3 seconds all on the bottom end even with a 4500 stall and 4.56s.

Be a good test to see how your does with a single plane vs a dual plane.

Skip; my Torker Is too! Much as we should pitch the T-Is in the creek, the mix distro is clean even, and for a 5 Lb manifold when cut, it beat a ton of others i tried.
Wensler Dual Quad won but tall and very heavy with carbs.

Probably ported about 8 T-Is and Sold em save 2. Spreadbore P4B is on right now for Dual-Plane peace of mind but no Street difference but maybe 1" more cold start vacuum. Like 4"-6" vacuum cold to hot idle g 9.0:1 from 30 cc dish).

Working the Spare 455+030: 78cc 48s, and Flattops. Studied and thinned my Cam files down to and very obvious set of information. Should Post and let the comments rip.

[GoatZillaRacing]

Originally Posted by mysticmissle

Do you know if there is room
In the spring package for
More cam? I’m
Going to put together a similar motor and test it in a friends lemans seems like tuff to beat for the money. Measure anyone out these on a motor w the speed master hr spring package? If so what cam

There is more room. Installed height is 1.800 and coil bind is .740. You can play with different locks and shims to dial in your perfect spring pressures. We do a lot of these heads with Howard's/Comp components to reach the customer's goal.

https://pontiacspeedshop.com/as-cast...eads-complete/

[Half-Inch Stud]

HYD Flat Tappet Cam sizes for the Street/Strip 455 and 4.25 stroke stuff & IRON HEADS:

High Compr, > 93 Octane to race, about 93 Octane to Street (with light ping on some weather); 245/255 110 LSA. Ref Lunati SPC1-320 or 30705.

Theory by Dave Vizard for the ideal cam (455 & 2.11" valve); 242/237 106 LSA, 102 ILC, but ya gotta custom that. Probably ping with pump gas.
Lunati 30707 238/242 110, less ping, Crane Fireball H-294 238/248 110 LSA for less ping than Vizard.

Optimal Cam for Street/Strip, heavy 10:1 92 Octane; 234/244 112 LSA Ref Wolverine 5059, Old Faithful, Tomahawk TH-02 HF, REF Jim Hand mid 11s Wheels-up 4300 Lb Wagon.
Crower 60211 236/242 108 LSA is close enough here.

Optimal Cam for Street/ Strip, med-light, 89 Octane; RA-IV copies 231/240 cut to 113 LSA Lunati 10703, Crower 60919, REF Cliff Ruggles 11.3 ETs. with Flat-footed street driving

PMD RA III H-cam 9795744, the Smallest Cam i would ever dare 224/236 119 for best of all Street but might ping on 87-89.

MY OPINION:
I prefer SLOW ramps (ADV Dur - 050 Dur > 60*) for safe Lifter-cam follow, least ping.
Medium ramps are ADV Dur - 050 Dur = 50-60: i dunno, just have good spring pressure.
FAST ramps are ADV Dur - 050 Dur < 50* ; lifter-cam disconnect with hi-rpm and weak springs.
I remain fearful of HYD Rollers with IRON HEADS due to fast ramps, yet just fine for Alum Heads.

I am amazed that Comp Cams made the Flat Tappet XE series of 050 Dur 206/212 through 250/256 with FAST FAST ramps. I think the term "Lifter Crashing" was coined by XE lobes. I suggest XE lobes provide enough Ping to overcome the crashing noise! Seriously who uses XE lobes and likes the Reliability and Performance?

Not a 400 engine guy but i think this list is a guide for 3.75" Stroke if 10* of the 050 Dur is removed from the above list. 400s are a wonderful engine, someday...

As for this Thread, HYD Rollers with aluminum heads works but i shudder to think about the ping when using the HYD ROLLER with Iron heads of same 050 durations.

[Half-Inch Stud]

My reading comprehension must stink. What are the HR cam specs on Post 1? and what Octane is needed for ping-free driving, vs Dyno-ing?

[leeklm]

Just one more nod to running lower timing with modern aluminum heads. My 461 with KRE provides it best numbers at dyno and track around 28/29 degrees advance. I live in the flatlands around 800 ft elevation and run 92/93 octane gas.

Sent from my SM-G965U using Tapatalk

[Cliff R]

+2

I run 28 degrees total timing on my 455. It runs equally as well at 30 degrees and I see no improvement going any higher. It starts to slow up slightly at 26 degrees, so I've been leaving it at 28 degrees total now for over 10 years, pretty close to a stock advance curve (all in just past 3000rpm's)with a positive stop welded in (HEI). I also add a few degrees from the vacuum advance (ported vacuum). Drives nicely and no detonation ever, even the few times I've ran 87-89 in it........

[Murf]

Originally Posted by Half-Inch Stud

My reading comprehension must stink. What are the HR cam specs on Post 1? and what Octane is needed for ping-free driving, vs Dyno-ing?

It says 226/236 @ .050.

I can’t answer the octane question.

Murf


Sent from my iPhone using Tapatalk Pro

[Half-Inch Stud]

Originally Posted by Murf

It says 226/236 @ .050. I can’t answer the octane question. Murf ...Pro

Well cammed. Pump Gas for sure, but i dunno if 87 happens. Wonder if 1.5:1 rockers are all that is needed on the EXH set.

[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.




.

[OCMDGTO]

OP/Druid, VERY nice build! Sounds like a great street engine. Always nice to hear real world results instead of some fantasy build. I'm definitely interested to hear how you like it in the car and any track results.

[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.

[J Druin]

Thanks to all for the input and no worries about hurting my feelings. As you can see I have been coming to this site a long time but rarely post. I just thought since I had not seen anyone post dyno numbers from a set of Speedmasters I would share. And yes, it was an actual dyno. Dale Meers Racing in Buffalo Ky. Before going to the dyno the machine shop that does my work said it is a conservative dyno, no inflated numbers. So, I thought between 400 and 450HP would be ok but hoping for the higher side. Oh, when I got there I was asked if I brought fuel and I had not so I went to the local gas station and bought 93 octane and that is what is was dynoed with.

[mchell]

Nice build!.... I would be pretty darn happy with that. We all hope for higher!

Personally, on a chassis or engine Dyno , I’ve NEVER had a Pontiac engine make what I thought it would make according to what I’ve read.

Be happy!

[72projectbird]

Gotta love these threads.

As soon as you post up your combo and dyno sheet, there's always comments about what is wrong with your combo and how they make more HP than you. Never fails.

[1968GTO421]

In looking at post #1 the OP shows his cam spec sheet where the lobe lift is 0.373 and the valve lift (with 1.5) is .560. Someone correct me if I'm wrong but this sounds to me like a hydraulic roller cam and not a HFT. It's not really important as I think his results are great. Gives me pause to rethink those Speedmaster heads.

[Steve C.]

Stated... "And yes, it was an actual dyno."

Thanks for the confirmation. Until today I was unaware Performance Trends has dyno software. That is why I brought up the subject.

This was sent to me....

https://www.performancetrends.com/dtm-dyno.htm


.

[Stan Weiss]

Originally Posted by Half-Inch Stud

HYD Flat Tappet Cam sizes for the Street/Strip 455 and 4.25 stroke stuff & IRON HEADS:

High Compr, > 93 Octane to race, about 93 Octane to Street (with light ping on some weather); 245/255 110 LSA. Ref Lunati SPC1-320 or 30705.

Theory by Dave Vizard for the ideal cam (455 & 2.11" valve); 242/237 106 LSA, 102 ILC, but ya gotta custom that. Probably ping with pump gas.
Lunati 30707 238/242 110, less ping, Crane Fireball H-294 238/248 110 LSA for less ping than Vizard.

Optimal Cam for Street/Strip, heavy 10:1 92 Octane; 234/244 112 LSA Ref Wolverine 5059, Old Faithful, Tomahawk TH-02 HF, REF Jim Hand mid 11s Wheels-up 4300 Lb Wagon.
Crower 60211 236/242 108 LSA is close enough here.

Optimal Cam for Street/ Strip, med-light, 89 Octane; RA-IV copies 231/240 cut to 113 LSA Lunati 10703, Crower 60919, REF Cliff Ruggles 11.3 ETs. with Flat-footed street driving

PMD RA III H-cam 9795744, the Smallest Cam i would ever dare 224/236 119 for best of all Street but might ping on 87-89.

MY OPINION:
I prefer SLOW ramps (ADV Dur - 050 Dur > 60*) for safe Lifter-cam follow, least ping.
Medium ramps are ADV Dur - 050 Dur = 50-60: i dunno, just have good spring pressure.
FAST ramps are ADV Dur - 050 Dur < 50* ; lifter-cam disconnect with hi-rpm and weak springs.
I remain fearful of HYD Rollers with IRON HEADS due to fast ramps, yet just fine for Alum Heads.

I am amazed that Comp Cams made the Flat Tappet XE series of 050 Dur 206/212 through 250/256 with FAST FAST ramps. I think the term "Lifter Crashing" was coined by XE lobes. I suggest XE lobes provide enough Ping to overcome the crashing noise! Seriously who uses XE lobes and likes the Reliability and Performance?

Not a 400 engine guy but i think this list is a guide for 3.75" Stroke if 10* of the 050 Dur is removed from the above list. 400s are a wonderful engine, someday...

As for this Thread, HYD Rollers with aluminum heads works but i shudder to think about the ping when using the HYD ROLLER with Iron heads of same 050 durations.

Mark,
David Vizard's Theory. This is from last summer. This was a work in progress at that time, but has no been worked on since.

Stan