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Speedmaster cylinder heads
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While waiting for a return phone call today I realized I had a pair of 72cc Edelbrock heads and Speedmasters waiting in line for some work. I studied them a bit side by side and thought I'd share a few observations.
Intake ports are CNC matched from both manufacturers. The Edelbrock in the first picture is blended and smoothed with a sanding roll. The second picture is the Speedmaster which is not blended or smoothed and leaves some large ridges which will have a negative effect on performance. The exhaust ports on the Edelbrocks are CNC matched (to a specific size) and the Speedmasters are as cast. |
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Both chambers are CNC machined and point the spark plug towards the exhaust valve. The Edelbrock chamber un-shrouds the plug and smooths out any exposed plug threads in the chamber.
Edelbrock head is on the right |
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The Speedmaster head's valve job was cut using a radius cutter on the intake and exhaust seats. The Edelbrock uses your basic multi-angle cutter on both.
The Edelbrock has the bowls blended and smoothed. The Speedmasters are not and they have sharp edges that need to be smoothed or some of their performance potential will be negatively affected. The Edelbrock head is on the left. |
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This picture has the SM valve on the left and Edelbrock on the right. The dye shows where the valve seat is located in relation the the valve face. Both intake seats had good placement. The exhaust seat on the E was good but for some reason the exhaust seat on the SM is located at the bottom of the face (closer to the valve stem).
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This picture shows an area of concern with the SM head. The intake bowl in this area is approximately .050 smaller that the valve insert. This is the area if you start chasing big power and open up the bowl it may cause the seat insert to fall out. It also causes an issue with shaping the bowl in relation to the valve job.
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FWIW
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Paul,
Good info, thanks for sharing! With as side by side comparison, it clearly looks like the Edelbrock head is more refined than the SpeedMaster based on your pictures.. Please keep us posted on any other findings as you set these heads up. |
Well, if there is not enough materiel under that seat to prevent them from falling out if one chooses to for big power, welding required.
Thats not good. Those Gabby E heads I have, under the area under the seat opened up is huge. The SM heads need some finish work. Those tests done by their manufacturer showing they flowed a bit more than the E heads, was that intake port blended ? You would think it had to be to outflow the E head. |
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Paul, first off thanks for posting this! Are the Edelbrock’s intakes roll sanded from the factory or had you already work on them? Do you have any plans to compare the flow of these heads? Thanks Murf Sent from my iPhone using Tapatalk Pro |
Thanks for posting.... glad I bought the originals ;-)
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Thanks for posing Paul - always nice to get first hand accounts of relatively new products.
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Murf - I assume you've seen Randy's (Goatzilla) thread on the SM heads and comparison to E-Heads https://forums.maxperformanceinc.com...0&postcount=16 That being said it would be nice to see another test. |
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The first set of E heads I purchased when they first came out were great here is a pic of the new ones I bought last year when they went on sale and and was very disappointed
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Thanks Paul for sharing. I was very close to picking these SM up on sale last November but realized it was only the price that was attractive. Glad I didn't and that was before you posted your thread.
So much for the SpeedMaster being the same as the Edelbrock and wonder if the advertised flow is on an as-sold head. |
Got a set of E-heads 2nd year they 1st came out. Where boxed as cast. Looked perfect everywhere.
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Thanks Paul for posting the info and pics. Food for thought. Reminds you that you get what you pay for.
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https://forums.maxperformanceinc.com...0&postcount=16 |
Paul,
I don't see anything that is a deal breaker there for me. Not that I'm shopping for heads or anything. But If I did I guess I would do some blending of the bowls. Seem like a couple hours of work to save $1200. However looking at the flow numbers it may not even be all that necessary. How significant is the exhaust seat alignment and the intake seat placement? |
Paul K,
Thanks for posting this information. This will help in making decisions since it seems it is getting harder to get Edelbrock heads. Seems some things will need to be done on the Speedmaster heads to take them up to standards we would all want. Nice to know there is an alternative. Thanks, Jim |
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Too bad the aftermarket cast iron heads never happened. |
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