We had heard good things about Trick Flow Specialties 23-degree aluminum heads. If the claim was true that we could expect serious horsepower gains over stock heads and even some aftermarket cast-iron heads, well then we just had to get our hands on a set. There was a project car going together that had a rebuilt stock 350 small-block and it was just right for finding out about "bolt-on" horsepower. With help from Summit Racing Equipment, we worked out a performance package that was reasonable for a street-driven '56 Bel Air and that would allow us to measure the impact of Trick Flow's heads.
Summit sent us a hydraulic Comp Cam and lifters, the Trick Flow Heads with pushrods and rockers, along with the very cool Trick Flow valve covers.
Summit Part Numbers were as follows:1.CCA-12-242-2 Comp Cam2. CCA-812-16 Hydraulic Lifters3. TFS-30400001 Trick Flow 23-degree Aluminum Heads4. TFS-21407850 Trick Flow 7.850 Chrome-moly Pushrods5. TFS-31400510 Trick Flow Rockers, 1.5 Ratio, 3/8-inch Stud6. TFS-31500802 Trick Flow Tall Valve Covers
The engine was built for civilized street performance with approx. 8.5:1 compression, a 650-cfm four bbl., and a TH350. The cam and valvetrain components were installed along with the original Chevy cast-iron heads. Then we did a baseline dyno run at the Primedia Tech Center. It turned out to be a fairly healthy little motor cranking out 215 hp with 300 lb-ft of torque. We had the feeling that it might take quite a bit to raise these numbers noticeably.
Once the Chevy iron heads were replaced with the Trick Flow Aluminum 23-degree set, we rolled the Tri-Five back on the same dyno. What a jolt! By simply bolting on these heads, we went to 270 hp and 341 lb-ft of torque. Wow! It's not that easy to get 55 more horsepower and over 40 lb-ft of torque, but we were looking at the proof. Of course, the car felt quicker and faster, but that seat-of-the-pants feel isn't like looking at the results of a dyno run. Remember, all we changed were the heads, so this is a 25 percent increase in ponies and close to 14 percent in stump-pulling power by just changing parts.
Yes, we know that these parts will set you back several hundred bucks, but there is very little else you can get for that price that will give you this big of a jump in power. It's also great to see the rpm range in which this power is achieved. There is a steady climb of horsepower that brings the maximum on line right around 5,000 rpm. That's a range reasonable for the street and a limit that should keep a small-block alive a long time, especially one with hydraulic lifters.
After our dyno time we spoke to Trick Flow and learned that they spent considerable engineering effort perfecting the runner design. The quality control on manufacture is such that runners and ports are extremely faithful to the design specs, avoiding the need for builders to do CNC-porting or other refinements when they purchase the heads. Our results seem to bear this out as the test results reflect "out-of-the-box" condition of all components. For street-driven cars that are meant to stay civilized these Trick Flow 23-degree aluminum heads are definitely worth a try.
23-Degree Heads for Small ChevyTechnical Specifications: Trick Flow 23-DegreeAluminum Cylinder Heads for SBC
Material: A356-T61 aluminumCombustion Chamber Volume: 64cc or 72ccIntake Port Volume: 195ccIntake Port Dimensions: 2.07 inches high x 1.26 inches wideExhaust Port Volume: 75ccExhaust Port Dimensions: 1.35 inches high x 1.50 inches wideValve Type: CNC-profiled, one piece, non-magnetic stainless steel with hardened tipsIntake Valve: 2.02-inch head diameter, 11/32-inch stem diameter, 4.96-inch OALExhaust Valve: 1.6-inch head diameter, 11/32-inch stem diameter, 4.980-inch OALValve Guides: Bronze alloy, .500-inch O.D.Seals: VitonValve Seats: Tungsten alloy, compatible with unleaded fuelsValve Springs:1.260-inch springs1.260-inch O.D. single with damper110 lb at 1.700 inches installed height290 lb at 1.200 inches360 lb per inch spring rate.520 inch max valve lift
1.470-inch springs1.470-inch O.D. single with damper120 lb at 1.780 iches. installed height300 lb at 1.280 inches360 lb per inch spring rate.540 inch max valve lift
1.460-inch springs1.460-inch O.D. double with damper125 lb at 1.780 inches installed height376 lb at 1.180 inches420 lb per inch spring rate.600 inch max valve lift
Valve Locks: 7 degree stamped steel on all 1.25-inch springs, 7 degree + .050 inch machined steel on all other spring versionsValve Retainers: Chrome-moly steelMax rpm: 6,500Rocker Studs: ARP 3/8 inch included with all headsGuideplates: For use with 5/16-inch hardened pushrods, included with all headsOEM Accessory Holes: Yes
Note: The use of a valvetrain combination that exceeds the maximum valve lift will void the warranty. Piston-to-valve clearance must be checked in all cases.
Recommended Components for 23-Degree HeadsHead Gasket: Fel-Pro 7733PT-2 for mild engines up to 4.060-inch boreFel-Pro 1010 for high output engines up to 4.155-inch bore (will not indent aluminum heads)Fel-Pro 1014 with pre-drilled steam holes for 400 engines (must modify heads)Intake Gasket: Fel-Pro 1205Exhaust Gasket: Fel-Pro 1404Head Gasket Kits: TFS-30400905 for mild engines up to 4.060-inch bore (pre-1987 only)Head Bolts: ARP-134-3601 (6 pt.) or ARP-134-3701 (12pt.)Head Studs: ARP-134-4001 (6 pt.) or ARP-234-4301 (12 pt.)Moly Lube: ARP-100-9902RTV sealer: Permatex Ultra Black #598BRThread sealer: Permatex Aviation Form-A-Gasket #3HThread locker: Loctite Blue #242 for medium strength applications or Loctite Red #272 for high-strength
Roller Rocker Arms: Crane Gold Race 1.5 ratio 11750-16 or 1.6 ratio 11759-16Trick Flow 1.5 ratio TFS-31400510 or 1.6 ratio TFS-31400511Summit 1.5 ratio SUM-G6910 or 1.6 ratio SUM-G6920
Note: All rockers fit 3/8-inch studs.If you use other brand rockers, you must check them for operating clearances and proper geometry. Stamped steel rockers should be used only with stock or very mild cams.
Pipe Plugs and Adapters:1/2-inch pipe plug-Aeroquip FCM-3749 (for plugging unused temperature sender hole)Adapter busing (1/2-inch male to 3/8-inch female)-Aeroquip FCM-2139 (for adapting 3/8-inch temperature sender)Pushrods: Refer to enclosed instruction manual.Headers: Will fit most headers. Check for proper fitment before installing heads on the engine. Refer to the Checking Header Clearance section in the instruction manual. Spark Plugs: The following spark plugs are recommended as a starting point:AC-FR3LSAutolite-324Champion-RC9YCNGK-FR5
Note: Make heat range adjustments based on tuning results. Blower and nitrous applications will require you to run a colder heat range spark plug. Try several heat ranges as needed.
Important Information For Emissions InspectionTrick Flow Specialties 23-Degree Aluminum Heads for '95-and-earlier 262-400-cid Chevrolet gasoline engines PN TFS-30400001 has been found not to reduce the effectiveness of required vehicle pollution control devices and are therefore exempt under California Vehicle Section 27156 permitting the advertising, sale, and installation of these parts for the 262-400-cid small-block Chevrolet V-8 gasoline engines.
This information is provided with the 23-Degree Cylinder Head. It can be presented at a smog inspection station during a smog check.