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I’m now offering a CNC program for the Procomp/Speedmaster Olds Cyl heads!
For all that have already purchased these but want more hp/tq you now have an option to greatly improve the heads you already have. We’re concentrating on flow rates at .600 lift (293cfm@.600) and below as that’s where most everyone has their engines cammed. As cast flow rates don’t exceed 240@.600 so this is a significant increase. In addition the combustion chambers are CNC’d to insure a truly “blueprinted” product.
Cost is $1875.00/pair using customer supplied complete heads. New 2.150” intake valves are also included in this package however.
Note; these flow numbers are greater than any out-of-the-box cyl head, even the new Edelbrock Gen III’s.
Thanks!
Last edited by cutlassefi; March 7th, 2022 at 07:21 AM.
What is the minimum cross section? Can you provide castings? If so what's the cost for a a bare set ported with valves and valve job? I have a few street motors coming up to build for customers. I may be interested in offering them this option. Thanks.
Do the Speedmaster valve guides use phosphorous bronze, manganese bronze or just plain bronze?
Wondering if Speedmaster valve guides should be used or use new valve guides? Speedmaster valve train parts leaves a lot to be desired. Definitely don't trust their valve springs and retainers.
Have you seen any Speedmaster heads have leaking issues when pressure tested?
So with a decent porting on the Speedmaster heads on a 455.
Cam 232/240 @ 0.50 with a .587 / .587 lift with 10.5:1 compression
Should make around 500-520 HP ?
Location: Colorado Springs Colorado/Thousand Oaks Ca
Posts: 1,721
Originally Posted by pettrix
Do the Speedmaster valve guides use phosphorous bronze, manganese bronze or just plain bronze?
Wondering if Speedmaster valve guides should be used or use new valve guides? Speedmaster valve train parts leaves a lot to be desired. Definitely don't trust their valve springs and retainers.
Have you seen any Speedmaster heads have leaking issues when pressure tested?
The valve guides should be replaced with quality valve guides, be prepared possibly for odd ball OD sizes. After porting it might be a good idea to pressure test.
The valve guides should be replaced with quality valve guides, be prepared possibly for odd ball OD sizes. After porting it might be a good idea to pressure test.
Maybe your Chevy stuff was a problem but these have been fine. I’ve had multiple different, reputable cyl head guys check these over the years for that reason. All said there was nothing wrong with them. If you don’t believe me just ask Bernard Mondello as he’s done hundreds of sets with no real issues. Now if you’re doing a full out race application I would think you’d want to replace everything anyway. But for a street performance build they’ve proven to be just fine.
And these heads are actually thicker in most areas than the Gen I and II Edelbrocks. We cut one up years ago before we did the first full port job. So again your recommendations are unfounded.
Last edited by cutlassefi; November 21st, 2021 at 05:36 AM.
Location: Colorado Springs Colorado/Thousand Oaks Ca
Posts: 1,721
The valve guide material used on a Procomp/Speedmaster BBC head is inferior to a CHE bronze valve guide, and it shows after use. I guess it could be possible the Procomp Olds head uses a valve guide with a different material than all the other Procomp head offerings but I doubt it. If I was offering these off shore heads (which I wouldn't) I'd be replacing the guides with CHE guides. The Edelbrock valve guides are made of a decent material along with the valves. With my limited experience with Procomp heads, I've seen no porosity issues.
One thing I found on a set of Pro Comp/Speedmaster heads I have is that the rocker arms from a BBC were too long. I ended up with a set of Scorpion Ford 1.72 : 1 full roller arms.
One thing I found on a set of Pro Comp/Speedmaster heads I have is that the rocker arms from a BBC were too long. I ended up with a set of Scorpion Ford 1.72 : 1 full roller arms.
That’s because BBC rockers have different geometry.
I’m now offering a CNC program for the Procomp/Speedmaster Olds Cyl heads!
For all that have already purchased these but want more hp/tq you now have an option to greatly improve the heads you already have. We’re concentrating on flow rates at .600 lift (293cfm@.600) and below as that’s where most everyone has their engines cammed. As cast flow rates don’t exceed 240@.600 so this is a significant increase. In addition the combustion chambers are CNC’d to insure a truly “blueprinted” product.
Cost is $1795.00/pair using customer supplied complete heads. New 2.125” intake valves are also included in this package.
Note; these flow numbers are greater than any out-of-the-box cyl head, even the new Edelbrock Gen III’s.
Thanks!
So with porting on the Speedmaster heads on a 455.
Cam 232/240 @ 0.50 with a .587 / .587 lift with 10.5:1 compression
Should it make around 500-520 HP ?
The valve guide material used on a Procomp/Speedmaster BBC head is inferior to a CHE bronze valve guide, and it shows after use. I guess it could be possible the Procomp Olds head uses a valve guide with a different material than all the other Procomp head offerings but I doubt it. If I was offering these off shore heads (which I wouldn't) I'd be replacing the guides with CHE guides. The Edelbrock valve guides are made of a decent material along with the valves. With my limited experience with Procomp heads, I've seen no porosity issues.
So in the video, it looks like the valve guides & valves were bad. That and/or the valve seats were bad. The casting looked OK. Basically the video is claiming Speedmaster castings are OK but the rest of the parts (valve guides, seats, valves, springs) are all bad quality.
28⁰ seems low. Mine is locked at 36.
I do want to dyno it to fine tune, though. I'm not consistent enough on the track to show gains or losses. Many variables.....
This is why I do the chambers too. Notice the area around the plug especially on the chamber on the right vs the other one. We’re finding this is very typical.
I want to get my heads over to you so badly I can hardly contain myself. As soon as I get a few upcoming moves nailed down, my heads are shipping right out to you.
What are your thoughts on upsizing the wimpy 7/16 head bolts up to 1/2 on a 396021F block? Drill and tap or Heli-coil? Or just leave it be? I don't know if there is enough meat in the block casting deck to do such a thing. I have always thought how wimpy the little 7/16 head bolts are on these. Once I get the bottom end of my "Project Cabrone" squared away (SCAT CNC billet 4.5 stroke full counterweight internal balance, DMR billet main caps, full 5 cap pan rail girdle), I am shifting this stroker beast over to E85 this time, so I want to get the compression up to a real 10.5:1 or 11:1 +/-, using the thinnest Cometic (or whatever) MLS head gaskets I can get my hands on. I know you have a lot of meat to work with on the heads, but I don't know if I want to mill the wee out of them so much that I would have to change pushrods and also machine the intake to match. Have you looked at backing off on how much material you are taking out of the chambers as a pliable factor to possibly accommodate?
These are the Mahle pistons I am running - the typical supplied with the Eagle stroker kit, but only at the smaller special order .030:
Hmmm, I don't recall how much below deck the piston tops are sitting at. I'll see if I can dig up my notes from the original build, or just re-measure.
Let me know your thoughts on changing up to 1/2" head bolts, and possibly modifying the program to leave a little bit more material in the chambers. To the best of my knowledge, .027" are the thinnest MLS head gaskets currently available. Maybe you know of something thinner that could possibly be sourced? Or, maybe I'll have to swap the pistons out to some flat tops. I would prefer not to as they only have 500 miles on them and the rings have seated in perfectly, but it seems that it may be inevitable to reach my compression goal with the chambers being extensively machined out on the heads while you work your magic on them...
What are your thoughts on upsizing the wimpy 7/16 head bolts up to 1/2 on a 396021F block?
Are you running a bunch of nitrous or forced induction? CR of 11:1 by itself won't stress the head bolts.
You could move up to ARP bolts, or ARP studs, at 7/16" and be absolutely fine.
Converting to 1/2" would be a lot of teardown, work, cleaning and reassembly for extremely little gain.
Are you running a bunch of nitrous or forced induction? CR of 11:1 by itself won't stress the head bolts.
You could move up to ARP bolts, or ARP studs, at 7/16" and be absolutely fine.
Converting to 1/2" would be a lot of teardown, work, cleaning and reassembly for extremely little gain.
I *always* run brand new ARP head bolts in my builds. I just worked with a 403 and liked the larger head bolt sizing, thinking it would be nice to have this size in my big blocks. I understand why the 403's had to go to larger head bolts, as there is just so little space between the bores. The only time I ever had a head gasket problem was on this car that I beat mercilessly:
455, EFI, full "rollermotor", Edelbrock heads (ported to the point of having to sleeve the pushrod holes) (yes, hit water a couple of times too), 175 plate, a genuine A833 HEMI 4 speed (only trans that would ever live behind this engine), Ford 9"... I used to make a lot of money street racing this car 20 years ago back in Detroit. I would take out any bike that was 900cc or less - miss that car...
I believe having to weld the heads in places where I hit water is when I started having head gasket problems about every 10k miles (was a daily driver punished mercilessly). I was running FelPro 1155 marine head gaskets back then. Since I have switched to Cometic MLS head gaskets on all of my successive builds, I have never had a problem since (save for some pesky oil seepage in the rear head drains).
Sooooo..... 7/16 bolts it is then (saves me a lot of work to have you say that!)
Now how are we going to hit a true 10.5:1 or better with the pistons I have and your CNC chamber port work? .027 Cometics, and mill a bit off of the head decks? Or do you think I'd be better off planning on swapping in some flat top pistons? I haven't priced any of those out yet that would fit the 4.5 stroke with the Eagle 7.100 H beams yet. Any suggestions? Since I am switching over to E85, which has the equivalent of 110 octane, I want to squeeze it pretty good. I will be running the Holley flex fuel package. My only fear is that I may be out on a road trip (HotRod Power Tour or otherwise) and not be able to find E85 whenever I need to, which means I will have to be sure that this can also run on E10 (most available pump gas). I know I can tune it to back off the timing and completely change the fuel parameters, but it is being purpose built for E85 this time around.
Think we can hit 10.5:1 or better without a piston swap out? As mentioned, I'd really prefer not to swap out the slugs, but it is what it is if that's what it takes. For what it's worth, I was punching out a solid 175 PSI on compression tests with the pistons shown, unmodified Speedmaster's, and the Cometic's at .042 compressed thickness. I have a set of the .027's on hand now for round two.
Let me know your thoughts - thanks again!
Paul
Last edited by Clark455; March 5th, 2022 at 10:32 PM.
You can mill the heads to 55cc if you want, plenty of deck thickness.
And good luck using the Holley EFI in flex fuel mode. You’ll need to configure that table yourself, lots of trial and error. And E85 can range from about 102 or so to about 110 octane, depending on the ethanol % and what they blend it with.
Last edited by cutlassefi; March 6th, 2022 at 07:00 AM.
I *always* run brand new ARP head bolts in my builds. I just worked with a 403 and liked the larger head bolt sizing, thinking it would be nice to have this size in my big blocks. I understand why the 403's had to go to larger head bolts, as there is just so little space between the bores.
My suspicion, and I'd love to hear Joe's take on this, is Olds went to 1/2" hardware across the board in 77 because of the diesel. The diesel needed the bigger hardware - well, it needed a completely different head attachment scheme, but that's a well known topic - and it was cheaper to just run all the molds and machines for 1/2" head hardware than keep separate lines/setups for 7/16 on the gas engines. They already had separate lines/setups for the 3" vs 2.5" mains, so no manufacturing change there.
Custom pistons usually run around $600-$800 for nothing fancy.
If you do the full chamber work bringing it out to 85cc, how much will you have to mill off to get the chamber into the area of 69cc? I have run all of the compression ratio calculations, using the following input data:
4.155 Bore
4.5 Stroke
69cc cylinder head volume (chamber)
+22cc effective dome volume (dish on my Mahle pistons)
.025 Deck clearance (estimated, not verified) (pretty sure that's what it was)
.027 Compressed gasket thickness
Yields a 10.75:1 compression ratio, which is target, allowing me to keep my existing pistons.
Soooo.... what amount have you observed that has to be milled off to get into that area of combustion chamber volume? (from 85cc down to 69cc) I am looking at the heads becoming effectively "shorter", which means I need to keep my pushrod lengths in mind and also my intake manifold interface. For instance, if the heads need to get wacked a solid .100", that will impact my pushrods (which I have another set of oil restricted custom rods on order and may be able to hopefully still change the effective length if needed), and may require my intake manifold to also be machined.
I have two sets of these Speedmaster heads - one set untouched out of the box measuring in at 3.870" from cylinder head deck to the valve cover machined mounting. The second set of Speedmasters I have were ordered with a 69cc combustion chamber. Measuring those heads from the cylinder head deck to the valve cover machined mounting is coming in at 3.815". From what I can tell of the scenario, the heads were milled .055" - .060" to bring the chamber volume down from the advertised 77cc down to 69cc - not enough to worry about pushrod length changes or intake manifold milling.
I don't know how many of these you have done yet, but hopefully enough to ballpark how much you will have to mill off to reduce from the CNC program produced 85cc down to a customer provided target of 69cc. Let me know please, as I may need to call ASAP to change the length of the custom pushrods I am having currently produced. If I end up having to mill the intake port flanges, then so be it.
As far as tuning, I have been doing EFI work since the '80's back when we had to custom burn chips (!). I have spent more time in parking lots uploading tuning changes over the years than I care to recall. I also have the support of some Holley engineers and aftermarket tuning wizards that can send me a bunch of tunes to get me in the ballpark, saving me a LOT of time by just having to do the final finesse tuning to suit my exact volumetric efficiencies / overall run characteristics. Besides being the previous owner of Unlimited Racing in Detroit, being an advanced engine performance certified ASE master tech, I have also been an overall carburation / tuning specialist for over 35 years - I have developed an instinctive feel for what an engine wants. I'll set up about 10 different tunes at my desktop, then get out on the road and upload any of the various tunes to home in on the best mapping, then probably spend the next 6 months playing around with an entire collection of tunes - it's definitely not for the average enthusiast, that's for sure!
Not sure why you wouldn’t just Dyno the engine to get a good baseline instead of investing months of tuning, but that’s your decision.
We’ll need to mill approx .090 off to get to 69cc.
And not sure why you would’ve ordered pushrods before your final mock up was done but again, your call.
Yes, you’ll need to mill the intake approx the same amount.
And if you do the math, your pistons should be less than .020 in the hole. That’ll help you figure comp as well.
Hope this helps.
Last edited by cutlassefi; March 8th, 2022 at 06:28 AM.
November 5th, 2021, 03:45 PM
I can hardly contain myself !!!
Just kicking around ideas
