Good call! Totally forgot that one. Closed chamber AND smaller bore/combustion chamber will permit much higher compression ratios for even more power (aside from the fact that aluminum heat dissipation would have to be considered--another .5-.75 point to compensate). Those custom pistons with quench platforms will be highly desired with these heads. These heads will transform the Buick 350 in more ways than one! I'm pretty stoked about these heads. I'd say DCR's of 8.5-9:1 would be doable on 93 octane, with 7.0-7.5:1 doable on 87! Maybe not the best placement, but is doable because Chevy small blocks with larger combustion chambers and proper quench are doing it. Offset ground cranks using those Nascar take-out rods Derek talks about not costing too much more would compliment a build with these heads nicely. Get some more cubes along with higher RPM potential... Hot damn there's a lot of potential here! P.S.--roller is the only way to go with these heads. Leave flat tappet to the iron. Gary
I've been over that pass (I think it was that one...maybe another one) in Colorado...in a Volvo 240 wagon lol. Well, mostly. Had to turn around when the terrain became too rocky. Lost a few chunks of tread out of those poor tires. That volvo was a tank! I think that carb would do just fine. May have to do some adjustment/tuning with the higher power output, but it's made out of the same alloys on this planet all the rest of the stuff is, so no god vengeance to worry about. :laugh: The TBI is a great idea too. I think if I had one of those, I'd try to get that set up on it just for the added stability for elevation and atmospheric conditions, along with better mileage and power. I think those TBI systems are 500 CFM too; not sure if they all are or if there were some with more CFM for larger CID engines. Either way, should work like a mule. Don't worry about being a 'guinea pig' on the heads. No such thing, as TA stands behind their work/products and these heads will outperform their iron counterparts in every way. These heads should bring the Buick 350 closer in line to the LS engines (notice I said 'closer') and that's saying a lot. Plus it's a BUICK. Gary
The Avenger TBI is a 4bbl with, I think, 750 or 900 CFM throttle bodies. The old 2bbl GM units and early Holly pro-jection were 670 I want to say.
Comparing a Buick 350 to an LS engine is a stretch even for you Gary. LOL You have to wonder if the chamber size is going to remain around 55 and become a closed chamber how is that possible? Only one way. The valves are moving deeper into the heads. That will make the short side radius even tighter on the intake side when maintaining the stock intake manifold location. Also from the rough casting looks like the exhaust ports are moving up. As I've posted before changing the valve angle and spreading them a little will allow bigger valves. Valve size is the biggest cork in the stock iron heads. The ports themselves are fine. Stop worrying about shrouding the valves. Just notch the block like a BB Chevy. They make plenty of power.
Going from a 10* to a 13* angle would relax the severity of the short turn a bit. Occasional mod on BB Mopar as well. Seems like a smart move. The other direction (raising the intake port location) would make the head a mile high. How the "too short" short turn is handled on many other aftermarket heads is to raise a hill up from the floor (dead area) and carry a larger radius over the top of it. The flow will keep fairly fast over that with the idea to stay tight to it and not ski-jump off or separate in some way. This can be the fastest part of the port when you probe it. The apparent sinking of the intake seat might not be sunk at all, a quench pad would accomplish the same effect without moving the depth any. Leaving material around the valve rather than the flow simply emptying into the chamber past the seat is a porter's dream, for many reasons. Are there many 270-280 cfm SBB intake ports already out there that the major restriction is the valve size? I would doubt that. I do agree that the changes listed so far are good moves and common sense from the perspective of a somewhat clean sheet. The head bolt pattern and intake opening leave LOTS of play area in between, where the most improvement would be. (Sorry Underdog, politely disagreeing with you there... :beers2: ) I'm only commenting in the general sense as I didn't design this head. Gary, just pointing out that when referring to SBC's, the aftermarket and vortec shaped chambers behave very differently than the 'ol wedge shaped chambers. Trapped compression ratios are not comparable nor are build strategies, including dis-similar rpm ranges applied to such (assuming similar materials, of course).
[QUOTEI might even be so bold as to say that using the TA dual plane intake and a large 2 barrel adapter with a low-lift roller cam to maintain good velocity within the lower section of the valve curtain, along with small primary tube headers, would make some seriously good grunt when comparing a similarly equipped Buick 350 with the old iron 2 barrel intake and iron heads.][/QUOTE] this is precisely my setup, only the carb/adapter is a GM TBI for the throttle body, and the TA manifold drilled for 450cc injectors from 2 Mitsubishi Eclipses, and the Burton Machine twin turbo kit instead of headers. With proper tuning, overdrive, EGR (yes, I'm running EGR. No, I'm not crazy, OK maybe a little) and aerodynamic improvements, I might get 25mpg highway! At least that's my goal. I'm downright giddy!
This works ok if the bowl is deep enough to add area over the shoprt turn If not,then as you say excessive air speed shown using a pitot will / can cause that dreaded jet engine sound on the bench Power will surely suffer in more max effort apps
Certainly! That area is pretty easy to change in a new casting. No need for water to be around the intake side of a head One might expect a near clean sheet to think of the basics. Mike's already said he has used flow boxes in the past and I wouldn't think this aspect would get past him. I didn't overlook that either, but I can't type up a dissertation every time I post :Smarty: The area we are referring to is often the minimum CSA and would be major concern for anyone redesigning a performance minded head, being that this section of head is largely responsible for the peak torque rpm at whatever short block it's marketed towards.
The 5.3 and Buick 350 are close in bore size, head port shape etc... The LS has a better block but not by too much and if we add the girdle we have a better foundation. I am all for both the LS and Buick 350 they are both great designs.
But you cant add CSA to a SBB It will ruin the magic Buick super torque mojo lol I like your thinking though
Who said anything about going overboard with the CSA? Weren't longer valves previously mentioned? The only reason for that being valve placement and installed spring height? Who's saying the stock SBB port is perfectly ideal and cannot be improved upon both powerwise or for driveability? Isn't correlating CSA and port characteristics relating to the cylinder and it's use the bare minimum one would consider? That's decades old. (I do know of a couple aftermarket heads that were OEM copies but with thicker walls. There was zero consideration for performance improvements) Why would it not be a natural to explore moving things around between the opening of the head and the valve? Simply easing the path to the valve evens out velocities as probed around the port, which gives some leeway to what works as far as other component selection. It makes the engine more tolerant of cam choices...it cures most 'evils' , lol. Being that part of the SBB magic is velocity and swirl, and that swirl is very effective proportionate to rpm/cylinder size ratios, it stands to reason that starting with a port that shows a slightly slower swirl energy (and better stability) would still retain it's low end magic and even extend it's usefulness to rpm and size ranges not intended by the factory castings, with the potential to suit a more serious use . (at least the as-cast condition and the final form of castings sometimes being the way they are for manufacturing ease, rather than the best net shape...) I can't figure out if you think TA hasn't thought of the very basics or if you are throwing entry level cylinder head talk at me for fun. ou: :beer:beer
I was being facetious is all about Buick folks adding any port volume As u eluded to it takes cross section to move the peaks in a hi hp piece My thought is too small pushrod area and large bowls are a compromise I guess its where you want your min csa to be is all The issue lies in the fact that a well ported OEM cast head will go 260cfm How come there aren't more 500 hp 350 Sb's??? The new heads will surely be an update but wont be the magic pill either Thanks to the Folks at T/A for stepping up as usual
Haha! 100% agreed. People seem to have the misunderstanding that CFM's control the powerband. Cams too. It's all about airspeed. My post was meant as a sarcastic response to yours as well. No malice intended.
