TFS's Twisted Wedge Heads for Small Block C'hevy's



Whatever happened to Trick Flow's Twisted Wedge Heads for SBC's?? They seemed like a really great idea.

For a guy like me who is trying to find a way to get a shallow valve angle head on LTx block and still retain a conventional valvetrain and conventional SBC headers without resorting to SB2.2 , 18* or 15* racing heads. These seems to the way to go. The 13* intake valve angle of the G1 and 16* intake angle of the G2 really intrigues me.

So how were they in real life??

If I find some on Ebay are they a good find?

Can they be effectively ported to support a high performance 396 ci LTx? (say 300 CFMs @ .500 lift)


Staff member
if you ever are asked what canted valves on a small block chevy heads are,
a good example are the trickflow brand twisted wedge head design,
the twisted wedge heads work great if your fully able to measure and set up a valve train geometry , the heads got a bad rep simply because most guys simply re-used the original push rods and never had a clue as to the differences in valve train geometry, or clearances.. certainly not a problem with the heads, but one with the lack of knowledge on the purchasers part.
heres the posted flow rate on the early G1 heads
these flow numbers significantly improve with minor port and bowl area clean up port work



now how well they flow depends mostly on if they were early G1 or later G2 production which heads they are referring too.
the early ones seem to have had less than satisfactory valve guides that wore out a bit more quickly, and some had some geometry issues,and their physical condition,and valve guide clearance should be checked along with the valve job and valve seal, and obviously clearances and valve load rates, and because they are aluminum head they require a steel valve spring seat cup under the valve springs
and in all cases its a very good idea to disassemble the heads and do some port and bowl area clean-up work with a die grinder in that port area under the valves as the factory machine work was deplorable, as they come out of the box, yet they can be made to flow rather well, almost as well as heads costing far more ,if your willing to do minor port clean up.

Im running G2 twisted wedge heads on my sbc 383 after a mild port job and they work great
your correct you need to verify push rod length carefully, I selected them, because at the engine I was building was designed for a heavy dose of nitrous and the twisted wedge heads have EXCELLENT exhaust flow characteristics
they easily added 45 plus hp to the engine over the stock L98 heads, even before being ported

even without mild porting these TWISTED WEDGE TRICKFLOW heads have exceptionally good exhaust flow numbers, once ported they are easily able to run with the more expensive 195 AFR heads, but by todays standards the 210cc AFR is a far better option
twisted wedge intake flow at .600 lift of 289- 300 plus depending on how extensive the work is, and exhaust flow numbers close to 240 are reachable
the TRICKFLOW G2 HEADS are no longer in production and really require porting the bowl area rather extensively, to flow to their true potential
Im using a set on my 383 in the corvette
don,t worry about the exhaust thats measured on a flow bench under a vacuum of 28" of water , equals roughly 13 psi
and in reality the exhaust port, flows as the engine runs under a positive pressure of over 80 psi, many times more pressure, and the headers provide a prolonged inertial pull.

Id also point out that cam timing matched to the exhaust scavenging has a huge effect on potential intake flow rates

















"There are 2 twisted wedge versions. The G1 and G2 (neither have canted valves). The G1 (what I have) has a 13dg intake valve angle and standard 23dg exh valve. They do require a special intake rocker but not on the exhuast. On the intake rocker the roller-to-trunion distance is shorter than a standard rocker. CompCams makes a specific rocker for the intake and is sold in sets of 8. This will go a long way towards proper geometry (along with correct length pushrods).

The exhaust valve is in the standard location but the intake valve sits about .400" closer to the intake manifold. This will require a fly-cut piston if your running a large cam. If you're under say 240dg duration and not less than 106icl and don't have milled heads or decked block you probably won't have any p-v clearance issues. somebody does make a girdle. JOMAR performance manufactures a 1 piece girdle that utilizes set screws and jam nuts. Cost about $175 with the proper poly-locks. Thought you might like to know if you ever decide to step up. The biggest problem with these heads is finding a roller spring that will set-up at 1.75-1.80". They're out there, but you gotta look. Mine will be replaced in a couple months with a set of Darts. They've been ported and shaved to 60cc. They made a little over 600hp and gobs of torque on my motor. If you're interested or know anybody that is, let me know.

Edit- Oh yeah, Yella Terra also makes a pedestal mount shaft rocker for the twisted wedge (but they don't specify if its for g1 or g2). Just something else to think about.

This info applies to the G1, the G2 has 16/18dg valve angles and the same does not apply. "

69camaro posted this info
"G1: 180cc intake port, 64cc chambers, 13* intake / 23* exhaust valve
angles, "stepped" pushrod guideplates, Teflon seals, cast iron valveguides.

G2: 190cc intake port, 67cc chambers, 16* intake / 18* exhaust valve
angles, "flat" pushrod guideplates, Viton rubber valve seals, powdered metal (Or optional manganese bronze) valve guides.

Both versions have 2.02"/1.60" valves. However, The G1 heads use a set of shorter (Intake is 4.450", Exhaust is 4.750" long) than stock valves. Stock length is 4.910" .... The G2 heads use a set of valves that are .050" longer than stock valves (4.960" intake, 4.980" exhaust)

Cleaning up the bowls & polishing the chambers / ports is always a good idea. Do not remove the swirl vane in the intake port as you will be givng up alot of power due to reduced homogenization of the incoming air / fuel mixture. You can smooth & blend the vane into the port some, But do not remove it.

basically untouched flow numbers

ported heads

Ive got a heavily ported set of those on my 383, they work great, at the time they first came out they were exceptional, but since then theres lots of high dollar heads that easily out perform them, they are still a decent head for high performance on a street/strip sbc.
read these ... ctions.pdf ... index.html ... to_03.html
Last edited by a moderator:


Staff member
It’s obvious that hot rod parts have evolved tremendously over the past 70 years or so. One of the best examples is the small-block Chevy cylinder head. A scant 30 years ago, the iron “fuelie” casting was the single choice for any small-block, race or street. Today, dozens of specialized heads are available for every type of small-block imaginable.

Recently you may have noticed race-only small-block heads with unusual valve angle designations, such as Chevy’s race-bred, 18-degree head. This refers to the angle of the valve in relation to the deck surface. Standard small-block Chevy heads position the valves at a 23-degree angle to the deck. In 1989, Chevy introduced the 18-degree Bow Tie aluminum head that shifted the valve angle vertically while simultaneously raising the intake port to take advantage of this angle. The advantage of the valve angle change is improved airflow due to placing the valve in a more “upright” position relative to the piston. Raising the port also necessitated a dedicated intake manifold, requiring a sizable cash investment to switch to these heads.


Trick Flow Specialties is an aftermarket cylinder head manufacturer best known for its excellent small-block Ford aluminum castings. Taking on the small-block Chevy market, it decided to take advantage of this valve angle change. Since interchangeability is so important, the first order of business was to ensure the head was a 100-percent bolt-on. This involved some compromise. First of all, the intake mounting flange would have to be compatible with the standard small-block Chevy intake manifold. Second, the valvetrain would also require significant modifications.

The intake valve was angled even more vertically, to a 13-degree angle. However, this valve angle change also required repositioning the intake rocker arm stud and mandated a new pushrod guideplate. These pieces are included with the Trick Flow Twisted Wedge head while retaining the use of stock-type rocker arms and pushrods. While the intake is dramatically altered, Trick Flow elected to leave the exhaust valve at its production 23-degree angle.

Altering the intake valve angle also changes the valve’s angle to the piston, which means the valve will not match the valve relief pockets machined into most small-block pistons. According to Trick Flow, camshafts with up to 238 degrees of duration at .050 tappet lift with a 106-degree lobe separation angle and .512-inch valve lift will work without requiring machine work to the piston valve reliefs.


Dyno testing is the only real way to evaluate engine components, so we collected all our parts and bopped over to John Baechtel’s Westech Performance Group facility to use his SuperFlow 901 dyno. To evaluate these new Twisted Wedge heads, we decided to baseline the test with a set of stock iron castings and then install the Trick Flow heads for comparison. The test engine was a 355ci small-block with flattop TRW pistons, a mild Crane HMV-266 dual-pattern hydraulic cam and a set of Crane 1.5-ratio aluminum roller rockers. The cam specs out at 210/216 degrees of duration at .050 with .440/.454 lift and a 114-degree lobe separation angle. The iron heads were rebuilt 882 castings equipped with 2.02/1.60-inch valves, guides, springs, screw-in studs and guideplates.

Since aluminum heads can tolerate a slightly higher compression ratio, Trick Flow equips the Twisted Wedge head with a 63cc combustion chamber (the 882 castings typically have 76cc chambers). Using a .041-inch gasket, compression computed out at 9.8:1, while the iron head compression came out at 8.9:1 using a .041-inch head gasket. The Trick Flow compression may seem high, but with aluminum heads this is a safe compression on 92-octane pump gas. In fact, Trick Flow recommends only 33 degrees of total timing, which also reduces the risk of detonation.

For induction we decided on a mild Edelbrock Performer dual-plane intake along with a matching Edelbrock Performer Q-jet carburetor. On the exhaust side, Hooker 15/8-inch primary tube headers vented the spent gas with an open exhaust, 18-inch exhaust collectors and Fel-Pro header gaskets.

As you can see from the power figures, the baseline combination made respectable power with the iron production heads, making 357 lbs-ft of torque at 3500 rpm and 294 hp at 5000 rpm. This is typical of a short-duration-cam small-block with stock iron heads and corresponds nicely with earlier tests on this engine. Now it was time to bolt on the Twisted Wedge heads.

With the engine still warm, we put on our Mechanix Wear work gloves and replaced the iron heads with the Trick Flow castings. With the ARP head bolts torqued, we installed a new set of Bosch Platinum spark plugs and buttoned up the engine with fresh Fel-Pro gaskets. After the engine was refired, we set the ignition timing at the same 36 degrees and ran the first test. Then we pulled the timing back to the recommended 33 degrees of total timing to evaluate that change. We were in the midst of studying jetting changes when our test came to an abrupt halt with the failure of a connecting rod (see “A Death in the Family”).

Despite the engine failure, we recorded a couple of full-power runs with the Trick Flow heads to give us a basis for comparison. Peak torque rpm increased from 3500 to 4000 and boosted torque to 392 lbs-ft (an increase of 35 lbs-ft), while horsepower improved 41 ponies from the baseline 294 to 335 at the same 5000 rpm. In addition, the Trick Flow heads carried the power further up the rpm scale, making 59 more horsepower at 5500 rpm over the stock heads (although the peak was still at 5000).


The flow bench tests revealed that the Twisted Wedge head enjoys a strong exhaust port compared to the intake port flow. This means these heads would probably perform best using a single- pattern camshaft with the same duration and lift on both the intake and exhaust lobes. Our test engine was equipped with a dual-pattern cam with more exhaust lift and duration, which is probably not necessary with these heads. We estimate by merely using a cam having the same duration and lift and by tightening the lobe separation slightly, the Trick Flow heads would probably jump to around 345 to 350 horsepower, for a 50-plus horsepower gain, while also pumping the torque curve.

We also believe that a single-pattern cam with duration of around 215 to 220 degrees at .050-inch tappet lift would make even more power, especially if combined with a high-rise dual-plane like the Edelbrock Performer RPM or Holley Contender intake. This cam choice would result in less idle vacuum and probably lope slightly at idle.

While the Twisted Wedge concept is not a radical improvement over other similar aluminum small-block Chevy cylinder heads, it delivers a comparable power increase over stock heads. One clear advantage is the price. Summit offers these heads (at the time this story was written) at about $200 a pair less than similar competitive aluminum small-block heads. The choice is yours. Wanna get twisted?

Read more: ... z26ZbrQ3Ff



Last edited by a moderator: