First post here so be gentle, new to the BBF, ran Clevelands and Windsors until now, just wondering if anyone has experience with the Speedmaster heads, I know they're rebadged Pro Comps and I'm not looking for the performance of an A head so I don't have unreal expectations, but after reading some Pro Comp horror stories I don't want to buy something that's unusable, rocker stands in the wrong place etc.. Ill be buying bare because I'm sure the valves and springs are junk, I just want a decent casting, and would like to hear from someone with experience with them, thanks.
drugdog
I have pair right here and can say that they have their place in the pecking order and having good machining (guide clearances checked, proper valve job, etc) and quality valvetrain parts installed is the answer. I think they are an excellent alternative to "resto-modding" 40 year old iron heads. You can read Scotty's write-up sticky and see that they can flow with iron heads, but in addition they: a. are so much lighter b. don't need new guides c. don't need hard exhaust seats installed (done already) d. don't need rocker stud pedestals machined off d. won't fail a preliminary mag/crack test forcing you to find another set.
That said, you began with not looking for A460 head performance, which is good. This is a stock-head replacement, not a full-on race head. If you want to use them on a racecar that is fine, but you can only get so much power out of them. You have to be realistic with the budget too. If you want a multi-thousand dollar race head, buy one. I like to think the ProComps are economical, so why dump tons into them? Some people spend money for CNC-ported, big-valve, triple spring beauties only to find their springs cracked through the over-ported intake ports.
I haven't heard of the machining for rocker studs being off. The valve seat machining is not always centered right with the guide, but that all wash out with your machine shop. That happens with a lot of big name heads too.
That said, you began with not looking for A460 head performance, which is good. This is a stock-head replacement, not a full-on race head. If you want to use them on a racecar that is fine, but you can only get so much power out of them. You have to be realistic with the budget too. If you want a multi-thousand dollar race head, buy one. I like to think the ProComps are economical, so why dump tons into them? Some people spend money for CNC-ported, big-valve, triple spring beauties only to find their springs cracked through the over-ported intake ports.
I haven't heard of the machining for rocker studs being off. The valve seat machining is not always centered right with the guide, but that all wash out with your machine shop. That happens with a lot of big name heads too.
Lots of BS stories out there from people who have never even seen a set in person let alone used them. I've built and used several sets, and never had any major issues. In fact, I've had way more quality issues with other more expensive alum heads.
In my opinion, they're a great alternative to re-working D0VE/D3VE iron heads, and performance is about on par or even a bit better when compression ratio and weight advantages are realized.
One thing most people don't realize is that they require a CJ flange header/manifold, and it's raised about .300 from the stock location. Something to consider if you're trying to use stock flange headers/manifolds or your clearances are tight to begin with.
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In my opinion, they're a great alternative to re-working D0VE/D3VE iron heads, and performance is about on par or even a bit better when compression ratio and weight advantages are realized.
One thing most people don't realize is that they require a CJ flange header/manifold, and it's raised about .300 from the stock location. Something to consider if you're trying to use stock flange headers/manifolds or your clearances are tight to begin with.
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Well the reason I'm cheaping out is this will basicly be a junk motor to learn with, a stock crank 466, decent rods, off the shelf flat tops. It will be my first go at blow thru and realizing the steep learning curve I don't want to be hurting a $3000 set of heads. Maybe it's not the way to go about it, but I thought I would throw together some "junk" to learn on while I save my pennies for the good stuff. If you think I'll have as much in machine work on the Pro Comps as it would cost extra to get SCJ's then I'd be crazy to go that route, thanks for the input guys, I'm all ears.
I guess it all depends on what you pay up front for the ProComps. The SCJ's are listed at $1540 and are going to be minimum $1400 bare/shipped for a pair (Summit, etc). If you pay $700 for a pair of ProComps shipped price from SpeedMaster on Ebay you are $700 ahead.
My machine shop guy won't just slap a set of valves and springs into a bare casting, so a competition valve job, valvespring height setup, guide clearance/honing would be equal cost for either head brand ((using the same FRPP 2.20"/1.76" valves ($200 good-guy price) and the same springs and retainers)).
Since you don't need milling to bump the compression, all that is different is the cost of enlarging the seats and bowl blending. That varies by shop, but since you are getting the valvejob, you shouldn't pay but a couple hundred out of that $700 difference
My machine shop guy won't just slap a set of valves and springs into a bare casting, so a competition valve job, valvespring height setup, guide clearance/honing would be equal cost for either head brand ((using the same FRPP 2.20"/1.76" valves ($200 good-guy price) and the same springs and retainers)).
Since you don't need milling to bump the compression, all that is different is the cost of enlarging the seats and bowl blending. That varies by shop, but since you are getting the valvejob, you shouldn't pay but a couple hundred out of that $700 difference
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