Speedmaster Cylinder Heads
Thread Starter
Melting Slicks
Joined: Mar 2009
Posts: 2,300
Likes: 115
From: Odessa FL
St. Jude Donor '10-'12-'13-'14-'15-'16-'17
Speedmaster Cylinder Heads
Anyone using, used, or heard of Speedmaster Cylinder Heads? I have seen advertisements for their heads with what looks like very good flow numbers, fully CNC, at a very inexpensive price and fully assembled. But as they say...if it looks to good to be true, it probably is. Any information would be appreciated. Thanks.
Melting Slicks
Joined: Jun 2012
Posts: 3,163
Likes: 6
From: Oceanside California
Im not really sure what to think of these heads. I have seen them on ebay before too. The price is a red flag to me because they claim to make the heads new from cast and CNC port them. This is expensive work..
The specs of the heads are good and the flow numbers are impressive. But I don't know that I believe them. It looks more like LS1 heads with the casting numbers machined off. Then machined down to LS6 equivalent combustion chambers. Also, why would they only offer them with .580" max lift springs?
I could be totally wrong, but it seems like they are ripping off old LS1 heads and making them their own. They probably do not flow that good at all.
The specs of the heads are good and the flow numbers are impressive. But I don't know that I believe them. It looks more like LS1 heads with the casting numbers machined off. Then machined down to LS6 equivalent combustion chambers. Also, why would they only offer them with .580" max lift springs?
I could be totally wrong, but it seems like they are ripping off old LS1 heads and making them their own. They probably do not flow that good at all.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I would be nervous just on the price. There have been castings in the past with porosity issues and I am wondering if these are what is being used. I know someone who this issue with another brand of head that used a new GM casting.
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
The are probably 5.3 truck head casting which are a dime a dozen. Nothing wrong with them and they do conform to the "LS 1-6" configurations. A good CNC company like WCCH can do a good job with them. You end up with something like a 243 head with higher compression. I'd be extremely wary of not only the CNC work but the guide work, seat cutting and the valves and springs used.
The adds I found show them marketed by SLP which gives me reason to pause in itself.
Budget parts are going to make budget power. Do it right and do it only once.
Just my $02
The adds I found show them marketed by SLP which gives me reason to pause in itself.
Budget parts are going to make budget power. Do it right and do it only once.
Just my $02
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
Now that I'm looking at them, their marketing could use some work.
Like all Speedmaster Cylinder Heads, the LS Series heads are produced using our "Gravity Casting Process". This process ensures a more uniform and robust casting, laying a strong platform to build on.
Last edited by Supercharged111; Sep 15, 2012 at 11:52 AM.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Melting Slicks
Joined: Mar 2009
Posts: 2,300
Likes: 115
From: Odessa FL
St. Jude Donor '10-'12-'13-'14-'15-'16-'17
The reason I was asking. I have heard of no one using these so became suspicious. For my needs I will stick with either having my 853's ported, upgrading the valve train or finding a set of 243's and upgrading them. Was curious however just to see if anyone out there had experience with them. Thanks.