I'm seeing some stroked 350's using those aftermarket rods, forged pistons, roller cam, these heads and the SP3 as the 'de facto' Buick 350 performance combination.
Once the aluminum heads are released, I'm sure a set will find their way onto Haydn's Stroker engine. Gary, any idea how much more power the aluminum heads might make on our setup, based on what we know about them as far as flow numbers?
I know you could safely bump the static compression about half a point and still use the same grade of fuel, due to thermal dissipation of aluminum vs iron. Even higher when you consider the closed chamber design of these aluminum heads. The smaller combustion chamber will aid in this as well, both in detonation resistance and increasing static compression. Using the same ratio, you'd see improvements with just the air flow. I would hesitate to say you'd see 100 hp from a direct swap, but 30-40 might not be unrealistic (a more conservative guesstimation). A change in the powerband and the engine's personality could be expected. This is all conjecture at this point, of course, but I have no doubts you'll see worthwhile improvements vs what you have now. We'll know more as additional details are released.
I REALLY would like to see the raw power difference between stock iron heads and "stock" AL heads. Straight bolt on. Stock rockers and everything. Take my SP 350 for example. Stock with a crower lvl 3, iron heads vs aluminum heads. Headers on both of course for testing purposes. If no one else does, if I ever get the heads I'll throw up the numbers off my local chassis dyno.
Keep in mind my comments were in regards to the aluminums vs his irons, which are already ported. Untouched vs untouched, the aluminums would blow away the irons so bad it wouldn't even be a fair comparison. There's just so many improvements over and beyond what even ported irons can offer, much less untouched irons.
I made a comparison some time ago (been many months I think--using the dyno program) showing what a 'stock' FM cs647 cam would do in a high flow environment that would normally see a much, much larger camshaft, and it showed damn near 500 hp (475 or thereabouts) lol! Just shows you where the real power is, and that is the air flow (mostly residing in the heads). The cam is just the 'middle man' in this negotiation of air movement.
Approaching 2 hp per cube isn't out of the question here with the right components on a N/A Buick 350. In fact, there was an engine builder many years ago (one of my tutors) back when I was young who told me that if you can't get 2 hp per cube, you're not doing it right. lol Watch and see.
When TA released the 455 Aluminum Stage1SE heads, they advertised a 50+ HP bump in a 10:1 SCR engine. My first engine was all iron, no head work, KB 118 cam, MT headers, and a 2 1/2" x pipe exhaust. With 3.42 gears, my best time was 13.22 @ 101 MPH. Static compression, calculated when the heads were removed, was 9.4:1. My SE aluminum heads got Gessler's Level 2 entry level porting (costs about 300.00). He milled them .040 for a 59cc chamber. That gave me 10.4:1. The heads flowed 313/225 @ .550 lift. With an Edelbrock Performer (some minor plenum work), the car went mid 12's @ 107+. Added an SP1, and 1000 HP Holley DP, and the car went a best of 12.20 @ 110 (QJ), and 12.11 @ 112 (1000 DP). That's 1.1 seconds and 11 MPH.
Speedtalk engine category (maybe advanced engine?) has had threads at various times with very well known and experienced people outlining exactly what type of improvements had to be made in order to regain the lost power when going from aluminum to iron same versions. It isn't a conversation good for promoting the aftermarket. As mentioned, any aluminum aftermarket head intended to replace stock production heads have many improved features designed to work in ways that overcome the material differences and shortcomings (as they would be if all things were truly equal, but then nobody would intentionally make them that way!)
I was on the fence about the aluminum heads, the wait and cost. But then I think I've now got forged rods, and soon forged pistons, I have my roller cam, SP3, 850 AED carb, JW 9.5" convertor, Janis T-350 trans with good internals, RobMc fuel pump and 1/2 pick up and lines. I decided to not punk out and use my irons, all the above with irons the car may run a bit better, I want it to run TONS better I don't want the engine constipated by iron heads.
And that's why these products exist, it isn't worth investing much into 'slight improvements'. If you think about it, a 1 man or other wise small shop gets killed trying to port iron heads competing with market prices. Tough to justify the shop's highest skilled guy using $100/hr shop time grinding 40-60 hrs. for an $800 set of iron heads that has a lot of other machining ops attached to it. In the 8-11:1 or so range, you can add compression, flow and a better chamber to make up for the thermal loss. You aren't anywhere near any diminishing returns as if you were switching from iron to aluminum with an already high flowing, good chambered, well engineered iron head at 14:1 and simply changing material. The aluminum is so much more cost effective to use for production on smaller runs anyways, so win-win. There's iron heads in demand and selling for over $2000 that I'd absolutely lose money porting let alone welding chambers, moving walls, etc. to get them competitive with high end aluminum heads.
I also would like to reiterate that with the closed chamber and aluminum material, static compression ratios will be able to soar over and beyond what the open chamber iron heads will permit on pump fuel. Safe DCRs that used to fall within the 7.5-8:1 range on open irons would probably be able to be bumped a full DCR point above this (8.5-9:1 DCR) and beyond. SBC engines with proper quench and even larger combustion chambers do it on a regular basis, and so the smaller chamber Buick 350 would be able to exceed this with no difficulty.
I want a set. Tim was saying maybe after the 1st of the year, more testing news. At least T/A doesn't have to deal with winter!
Yes if they're a good starting point. One of the import head co's has an extremely tempting program for buying them CNC'd through their source that makes sense when you consider purchasing a pallet at a time. The raw head is nowhere close to flowing what's advertised. The CNC'd version is less than impressive at best. It's cheap enough yet that you would consider the CNC work to be a cost effective method to get some of the material out of the way and be serious with it. Even if you were doing a crate motor program you'd still lose your butt solving machining problems and re-engineering things to be able to bolt them together, along with a massive overstock of varying complimentary components needed fit each one as they are so inconsistent. At the end of the day there are others using the same head at a better price with less lead time that don't seem to mind questionable quality attached to their business.
It will be interesting to see how my first hand ported versions perform vs the second set that scotty brown is CnC porting...
Anything's possible in the hands of an expert. If there's a difference it's simply because the finished port was intended to be the way it is and how that fits into your build. One may hit YOUR mark better. Obviously my example is showing that the CNC carving is kept quite conservative for production reasons and more for high sales #'s in the particular demographic it's mass marketed for. I'm sorting out a fairly spendy CNC head now that has a huge port angle mismatch with the intake suggested for it. It is in the Summit catalog and fairly reputable...a victim of a poor tech suggestion and companion part. The head flows decent, the intake flows decent, just in different directions Anything like this Buick project with devoted attention that's purpose intended is going to be better than the mentioned.
If Greg Geisler was still doing head porting, I wonder what he could do with a set of the 350 aluminum heads. Tim
