HPR 468 peaking to low.
Thread Starter
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Joined: Feb 2018
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From: Lawrenceburg Ky
No man I don't, the heads came from Tony Mamo. I actually wanted the TSP roller tip rockers which I've used in the past with great success, but at the time TSP didn't haven't them and didn't know when they would because of covid-19.
The YT rockers that he’s using are 10.5 grams over the nose heavier than an OEM steel rocker. I’ve done the math. 10.5 grams is a lot of weight, don’t get me wrong, but not substantial at 6500-7000 rpm. 8000+ rpm is a different story. Tony sets the springs up to handle the rockers. I have the same setup, and my limiter is set to 7800 and I’ve been up over 8k many times without issue. The hollow intake valves are 3 grams lighter than the exhaust valves.
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That was my first thought. I bet the intake he has can easy peak at over 7k with a bigger cam
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Erik's Still got a Sense of humor....
CID and 4500....Old Conversation on YB about 468 thru 528 inch combinations and What guys are or where using.... A 105-112mm 🤣😂 and the Air is coming from the Front....Bad idea? Engine love it's Air Stream line = Air from the Top Carb style.
Run it & get a Baseline...😂🤣 a few said this.
You can Control a Heavier Valve with a good Spring so As Long as the Rocker it Self is Stable....
I know of Guys With Studs and Girdles running 8500 it may Not be the Best but So as Long as it's
Sturdy..
CID and 4500....Old Conversation on YB about 468 thru 528 inch combinations and What guys are or where using.... A 105-112mm 🤣😂 and the Air is coming from the Front....Bad idea? Engine love it's Air Stream line = Air from the Top Carb style.
Run it & get a Baseline...😂🤣 a few said this.
You can Control a Heavier Valve with a good Spring so As Long as the Rocker it Self is Stable....
I know of Guys With Studs and Girdles running 8500 it may Not be the Best but So as Long as it's
Sturdy..
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Oh boy! Look at that!
I've Been Told by a Guy about this Combination .....
And it's CSA and MCSA
🤫
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A Great Shaft mounted Rocker arm Should be a Minimum Mandatory with Any high End build.
https://www.efi101.com/valve-train-t...tem-stiffness/
Last edited by Corona; Jul 13, 2021 at 12:36 AM.
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A 102 TB actually flows closer to 1400 CFM at 20" of water (or 1.5" of mercury....both representing the same pressure drop and the "standard" most carbs and throttle bodies are flowed at)
On paper a 102 straight pipe with a radiused entry would flow 1550 ish CFM but throw the blade and shaft in there (a small obstruction) and the little bit of curvature built into the bore housing to help give it some drivability and your looking around 1400 CFM
Some of my ported 90mm TB's flow 1200 CFM and the difference looking down the mouth of both of them is quite substantial.
All that said with EFI engines more air usually makes a little more power even though on paper the engine demand for airflow would tell you it wouldn't be needed.
Looking at the KPA reading from the dyno pulls is the best way to determine the type of restriction there is on the inlet side of things and even then the TB only represents part of that equation.
Not sure why numbers and a dyno sheet isn't being shared here with the community as there is info to be gleaned from the shape of both curves (power and torque) but I suspect this engine will run pretty strong and will still show the best track results shifting north of 7000 RPM
-Tony
On paper a 102 straight pipe with a radiused entry would flow 1550 ish CFM but throw the blade and shaft in there (a small obstruction) and the little bit of curvature built into the bore housing to help give it some drivability and your looking around 1400 CFM
Some of my ported 90mm TB's flow 1200 CFM and the difference looking down the mouth of both of them is quite substantial.
All that said with EFI engines more air usually makes a little more power even though on paper the engine demand for airflow would tell you it wouldn't be needed.
Looking at the KPA reading from the dyno pulls is the best way to determine the type of restriction there is on the inlet side of things and even then the TB only represents part of that equation.
Not sure why numbers and a dyno sheet isn't being shared here with the community as there is info to be gleaned from the shape of both curves (power and torque) but I suspect this engine will run pretty strong and will still show the best track results shifting north of 7000 RPM
-Tony
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www.mamomotorsports.com
Tony@MamoMotorsports.com
Anything worth doing is worth doing well. Build it right the first time....its alot cheaper than building it twice!!
www.mamomotorsports.com
Tony@MamoMotorsports.com
Anything worth doing is worth doing well. Build it right the first time....its alot cheaper than building it twice!!
They do make bigger throttle bodies. May as well just slap one on and try it. My guess is you are correct, it's a choke of some point. Could be valvetrain going nuts, but would probably show it on the dyno different. When you are at the level you are at, change one thing at a time and test. Data is you friend.
But if your dyno basically looks like this, I would think the valvetrain was doing fine:
Thread Starter
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From: Lawrenceburg Ky
A 102 TB actually flows closer to 1400 CFM at 20" of water (or 1.5" of mercury....both representing the same pressure drop and the "standard" most carbs and throttle bodies are flowed at)
On paper a 102 straight pipe with a radiused entry would flow 1550 ish CFM but throw the blade and shaft in there (a small obstruction) and the little bit of curvature built into the bore housing to help give it some drivability and your looking around 1400 CFM
Some of my ported 90mm TB's flow 1200 CFM and the difference looking down the mouth of both of them is quite substantial.
All that said with EFI engines more air usually makes a little more power even though on paper the engine demand for airflow would tell you it wouldn't be needed.
Looking at the KPA reading from the dyno pulls is the best way to determine the type of restriction there is on the inlet side of things and even then the TB only represents part of that equation.
Not sure why numbers and a dyno sheet isn't being shared here with the community as there is info to be gleaned from the shape of both curves (power and torque) but I suspect this engine will run pretty strong and will still show the best track results shifting north of 7000 RPM
-Tony
On paper a 102 straight pipe with a radiused entry would flow 1550 ish CFM but throw the blade and shaft in there (a small obstruction) and the little bit of curvature built into the bore housing to help give it some drivability and your looking around 1400 CFM
Some of my ported 90mm TB's flow 1200 CFM and the difference looking down the mouth of both of them is quite substantial.
All that said with EFI engines more air usually makes a little more power even though on paper the engine demand for airflow would tell you it wouldn't be needed.
Looking at the KPA reading from the dyno pulls is the best way to determine the type of restriction there is on the inlet side of things and even then the TB only represents part of that equation.
Not sure why numbers and a dyno sheet isn't being shared here with the community as there is info to be gleaned from the shape of both curves (power and torque) but I suspect this engine will run pretty strong and will still show the best track results shifting north of 7000 RPM
-Tony
There is nothing special to see on my dyno sheet, it ramps up about 6k (stall speed), hits max hp at about 6500, and drops only about 10hp from 6500 to 7k, no funny looking spikes or dips. You could almost lay a framing square on my power curve. It makes more power and torque than my old 447 and that's good enough for me. Would just like to shift the peak up some if I can.
Simply put track numbers are the only numbers that matter to me and I will happily post those numbers once I have them.
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From: VA
No offense, but your chasing 500rpm if you spend x amount of money to gain rpm you may then have to spin the motor 7500rpm+ You are a seasoned veteran at the track. Go run it and see where you are and dial her in a bit. I think you will meet your goal and spend your hot rod money on a nice vacation this winter 
Thread Starter
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From: Lawrenceburg Ky
No offense, but your chasing 500rpm if you spend x amount of money to gain rpm you may then have to spin the motor 7500rpm+ You are a seasoned veteran at the track. Go run it and see where you are and dial her in a bit. I think you will meet your goal and spend your hot rod money on a nice vacation this winter
Last edited by BigDaddy97; Aug 27, 2021 at 10:14 PM.
If I had an engine dyno around my area I would certainly have shared my dyno sheet and numbers. On the other hand a chassis dyno is way to easily manipulated in my opinion. If the numbers don't suit a person, you can go across town to another one that "reads" higher and get bigger numbers or I could replace my heavy 29.5 drag radials with lighter 28" bias ply slicks and get a bigger number. A guy with the same engine as me and a manual transmission is gonna dyno a lot more than me because I'm running a powerglide and a 8" 6000 stall even though I'm most likely faster at the track. For me, a chassis dyno is just a tool to see where my peaks are and to get a baseline so that I can see if there is a gain or loss on power if I were to change a cam, throttlebody, intake, etc. The numbers themselves mean nothing to me.
There is nothing special to see on my dyno sheet, it ramps up about 6k (stall speed), hits max hp at about 6500, and drops only about 10hp from 6500 to 7k, no funny looking spikes or dips. You could almost lay a framing square on my power curve. It makes more power and torque than my old 447 and that's good enough for me. Would just like to shift the peak up some if I can.
Simply put track numbers are the only numbers that matter to me and I will happily post those numbers once I have them.
There is nothing special to see on my dyno sheet, it ramps up about 6k (stall speed), hits max hp at about 6500, and drops only about 10hp from 6500 to 7k, no funny looking spikes or dips. You could almost lay a framing square on my power curve. It makes more power and torque than my old 447 and that's good enough for me. Would just like to shift the peak up some if I can.
Simply put track numbers are the only numbers that matter to me and I will happily post those numbers once I have them.
Thread Starter
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From: Lawrenceburg Ky
Just tossing around ideas here and investigating all options: I read through fnbadazz06 468 build post and saw that he showed a decent gain and peak rpm change by adding a 112 throttlebody to his carbon 105 intake using an adapter. I was on the Visner site and they sell a big oval port throttlebody and a oval port to 105 mm adapter. Anyone here used that Visner oval throttlebody? Again just gathering information
Thread Starter
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From: Lawrenceburg Ky