trickflows 18 degree head 358 combo

grumpyvette

Administrator
Staff member
Testing the Trick Flow Head

The Trick Flow 18 degree heads we dyno tested came with as-cast 250cc intake/100cc exhaust runners, 56cc combustion chambers, 2.150 in./1.625 in. stainless valves, and 1.550 in. dual valve springs. The flow bench data on these heads was impressive: maximum intake flow was a steady 328 cfm from .550 in. to .700 in. lift; max exhaust flow was 255 cfm at .650 in. lift. In the hands of a skilled head porter, the Trick Flow heads can be made to flow a bunch more.

Dyno Engine Specifications

Displacement and Compression: 358 cubic inches, 9.5:1 compression
Block: Bowtie iron, 4.125 in. bore
Crankshaft:Trick Flow forged, 3.330 in. stroke
Connecting Rods:Trick Flow forged, 6.125 in.
Pistons:JE forged, -19cc dish
Camshaft:Iskenderian mechanical roller, 264/268 degree duration @ .050 in., .645 in. lift
Intake Manifold: Bowtie single plane
Carburetion: Holley 830 cfm double pumper (Test 1), Demon Carburetion 825 cfm Race Demon/RS (Test 2)
Ignition: MSD Pro-Billet distributor, MSD 6AL ignition box
Exhaust: Dyantech step headers (1 3/4 in. to 1 7/8 in. primary), 3 1/2 in. Flowmaster mufflers

The test engine was a relatively mild 358 cubic inch small block with 9.5:1 compression. Set up like a late model circle track engine, it has a Bowtie 4-bolt block, 3.330 in. stroke Trick Flow forged crank and 6.125 in. forged rods, JE dished pistons, a .645 in. lift Iskenderian roller cam and lifters, Jesel shaft rockers, and a Chevy Bowtie single plane intake. Two carburetors were used -- a tried and true 830 cfm Holley double pumper and a Demon Carburetion 825 cfm Race Demon/RS. This was the first time we had seen a Demon in action, and we were anxious to see if it performed as good as it looked (see "Caution: Demons at Work" for details on the Race Demon).

The test results were as impressive as the flow bench data, especially when you consider the mild compression ratio. With the Holley, the 358 made 607 HP at 7,250 rpm and 472 ft.-lbs. of torque at 5,750 rpm. With the Race Demon/RS bolted on, horsepower edged up to 620 HP; torque stayed about the same at 474 ft.-lbs. Trick Flow plans on dynoing the heads on a more serious 12 or 13:1 compression engine, and fully expects even more dramatic power figures.


Trick Flow 18 Degree Head Flow Data
Head tested on Quadrant Scientific Flowlab 1400
flow bench at 28 in. of water pressure


Intake Flow Exhaust Flow
Lift CFM Lift CFM
.300 in. 217 .300 in. 152
.400 in. 276 .400 in. 198
.450 in. 298 .450 in. 209
.500 in. 316 .500 in. 219
.550 in. 328 .550 in. 225
.600 in. 328 .600 in. 231
.650 in. 328 .650 in. 255
.700 in. 328 .700 in. 237

There's no doubt that Trick Flow's 18 degree heads can make serious power--power ideal for high rpm circle track or Super-Class drag racing. While they're not bargain-basement heads by any means, they are a good deal when you consider the large amounts of time and money you would spend on making a set of 23 degree or other 18 degree heads perform at these power levels. It seems as though the Trick Flow 18 degree heads are a bargain after all....
 
Back
Top