Discussing course shift on the intake ports of the Pontiac Speedmaster, Cylinder Heads. Issues with transition on the exhaust porch between the valve seat and the bowl area.
I bought a pair of speedmaster bare castings for Oldsmobile. A lot of similar issues. Still an affordable, lighter option. I'm going to take my time and get them right.
I agree, the castings aren’t perfect but it flows more than stock casting heads and being aluminum is a great upgrade. Thanks for watching and the feedback! JD
This may not be as bad as it looks. I'm not a head porting expert, but what I've seen done by clever porter's, they cut the throat at 90% or slightly bigger, and bowl is 100% of the valve diameter. Basically exactly what you had to do there due core shift. I don't know the physics, why the port flows more by making bowl bigger than throat, but some experts do that so it must be good :)
Yeah, the bowl sometimes is around 104% on some heads. It really depends on the attack angle of the air on the back wall of the bowl. I like to use 90% on the throat and radius as smoothly as possible without increasing the angle of the turn. The bias side of the port is worked more; it gets wordy to try and explain. Thanks for your feedback! JD
Would these as cast be better than 7f6 heads? I own a 1972 455HO with the 7f6 heads and thinking about some aluminum pieces. My engine is 30 over with TRW L2394 pistons , which I don't think my Ole pistons will work with these combustion chambers. I think the dome is .416. I'm going th need new pistons. Love your work , I commented on the intake height on one of your videos.
Be careful with maintaining the value of your classic Pontiac. I wish the fit and finish of these Speedmaster heads were better out of the box. With this said the Speedmaster heads will greatly out perform stock imported 7f6 heads. Your HO heads flow maybe 220-225 cfm compared to 280+ cfm of the aluminum heads. Why are you running such a high dome piston? We’re you running race fuel only? I’m not familiar with the usage of your Pontiac. JD
@HeadFlowInc The engine was built in 1973 at a machine shop in Rockingham nc. My dad bought the engine out of the trans am when the owner parted the car out to get money for college. Mid 1973 , he stored it for many years, he passed in 96 and I bought the engine from my mom. I do run 110 race fuel in it. I spoke to Jim at Butler about buying rings for the old pistons ,and he said I need updated parts. He said the pistons are heavy and the dome interrupts flame travel. I have just kept it as it was built from 73 besides just rings and bearings and new cam. It had a General Kenitics cam in it. You may remember that company from the 60s and 70s. The engine is a beast , sounds like a B-29, lol. I plan on updating it soon and want to save the 7f6 heads as they are kinda rare. I figured you know your stuff and respect your opinion.
I’ve had some unforeseen delays due to health issues, moving homes and setting up a new shop. I have unfortunately not finished these heads yet, but they are on the bench as we speak. Please look for upcoming videos on these Speedmaster heads, thank you.
I use MiG Tip grease, I try to apply the grease when the burr is warm so it melts into the burrs. You don’t want to put to much on when it’s cold, it’ll sling everywhere inside the port and make a mess. Any brand, I use Hobart because it was easy to find locally but I bet way cheaper online! 👍
Who flowed out of the box Pontiac Speedmaster heads? Share a link to their article or channel so everyone can see. I’ve done extensive Google searching I can’t find a single person who ever followed through with flowing a set of speed master Pontiac heads out of the box. I promise you these cylinder heads could not produce 290 CFM as delivered. I’m not saying they don’t run OK but I promise you you’re not gonna put them on and make 600hp.
Was so happy to see this! Thank you , much appreciated to see some Pontiac Contents!
Thank you for watching and the feedback! JD
Keep it up! Your video flow has really improved. Like you said more engaging overall. Always good truthful to the point content.
I'M GLAD YOUR BACK!
Thank you!
I bought a pair of speedmaster bare castings for Oldsmobile. A lot of similar issues. Still an affordable, lighter option. I'm going to take my time and get them right.
I agree, the castings aren’t perfect but it flows more than stock casting heads and being aluminum is a great upgrade. Thanks for watching and the feedback! JD
Great information!
This may not be as bad as it looks. I'm not a head porting expert, but what I've seen done by clever porter's, they cut the throat at 90% or slightly bigger, and bowl is 100% of the valve diameter. Basically exactly what you had to do there due core shift. I don't know the physics, why the port flows more by making bowl bigger than throat, but some experts do that so it must be good :)
Yeah, the bowl sometimes is around 104% on some heads. It really depends on the attack angle of the air on the back wall of the bowl.
I like to use 90% on the throat and radius as smoothly as possible without increasing the angle of the turn. The bias side of the port is worked more; it gets wordy to try and explain. Thanks for your feedback! JD
👍👍👍
Would these as cast be better than 7f6 heads? I own a 1972 455HO with the 7f6 heads and thinking about some aluminum pieces. My engine is 30 over with TRW L2394 pistons , which I don't think my Ole pistons will work with these combustion chambers. I think the dome is .416. I'm going th need new pistons.
Love your work , I commented on the intake height on one of your videos.
Be careful with maintaining the value of your classic Pontiac.
I wish the fit and finish of these Speedmaster heads were better out of the box. With this said the Speedmaster heads will greatly out perform stock imported 7f6 heads. Your HO heads flow maybe 220-225 cfm compared to 280+ cfm of the aluminum heads.
Why are you running such a high dome piston? We’re you running race fuel only? I’m not familiar with the usage of your Pontiac. JD
@HeadFlowInc
The engine was built in 1973 at a machine shop in Rockingham nc. My dad bought the engine out of the trans am when the owner parted the car out to get money for college. Mid 1973 , he stored it for many years, he passed in 96 and I bought the engine from my mom. I do run 110 race fuel in it. I spoke to Jim at Butler about buying rings for the old pistons ,and he said I need updated parts. He said the pistons are heavy and the dome interrupts flame travel. I have just kept it as it was built from 73 besides just rings and bearings and new cam. It had a General Kenitics cam in it. You may remember that company from the 60s and 70s. The engine is a beast , sounds like a B-29, lol.
I plan on updating it soon and want to save the 7f6 heads as they are kinda rare.
I figured you know your stuff and respect your opinion.
How much time and money did it take to fix this
The port to seat offset wasn’t changed only smoothed. To fix these heads would have cost way more than they’re worth.
I am front Kansas City, building a 4.8, am up to the heads and lost. Would love to chat. Is there any way to reach out?
Send me a message…
jeffdubray@gmail.com
Are you done with these, I’m curious to see the results.
I’ve had some unforeseen delays due to health issues, moving homes and setting up a new shop. I have unfortunately not finished these heads yet, but they are on the bench as we speak. Please look for upcoming videos on these Speedmaster heads, thank you.
@@HeadFlowInc I hope you get better!
What would ya charge to port a ford version of those heads. I just bought some off of a guy super cheap and wanna get them fixed up
Send me a note:
Jeffdubray@gmail.com
How do you keep your burrs from clogging up so quickly?
I use MiG Tip grease, I try to apply the grease when the burr is warm so it melts into the burrs. You don’t want to put to much on when it’s cold, it’ll sling everywhere inside the port and make a mess. Any brand, I use Hobart because it was easy to find locally but I bet way cheaper online! 👍
@@HeadFlowInc that would probably work better than my ole WD-40. Thanks
👍
Well they do flow that. Been flowed by a known Pontiac guy,
Who flowed out of the box Pontiac Speedmaster heads? Share a link to their article or channel so everyone can see.
I’ve done extensive Google searching I can’t find a single person who ever followed through with flowing a set of speed master Pontiac heads out of the box. I promise you these cylinder heads could not produce 290 CFM as delivered. I’m not saying they don’t run OK but I promise you you’re not gonna put them on and make 600hp.
@@HeadFlowInc Rocky Rotella for Poncho Perfection. 290 @ .600
@@HeadFlowInc Randy at Pontiac SpeedShop got similar numbers.
@@scottnorris8571 Link?
@@scottnorris8571 Link?
In other words junk
For the price and availability it’s an option. They do at least offer an aluminum option that flows more than a stock casting. JD