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The time has come, and our new DHC 175 cylinder heads for small block Chevy are available for purchase! They are being assembled as we speak, and will be shipping by the end of the week!
Trick Flow's new DHC 175 cylinder heads give small block Chevy enthusiasts a new performance option. No longer will anyone have to choose between vintage looks or modern cylinder head power, with DHC 175 heads you get both!
DHC 175 heads are made from premium grade A356-T61 aluminum and have the exterior styling and straight spark plug holes that deliver the nostalgic appearance customers want. On the inside, 60cc CNC-profiled combustion chambers with blended bowl machining under the valves and small cross-section intake runners promote low-RPM torque increases and boost high-RPM horsepower! The runners are finished with Trick Flow's superior Fast As Cast process that precisely duplicates the runner profile and performance levels of fully CNC-ported heads without the added machining cost. In keeping with the vintage design, the heads are available with or without accessory bolt hole cast into them.
Not only that, 40 lbs. comes off the nose of the car! $740.97 ea. with .600 lift Hydraulic roller springs...with or without accessory bolt holes drilled. On a 350, 60cc chambers net 10.6:1 with your average 5cc flat top piston, .040 gasket, and .010 in the hole at tdc. This is fine for pump gas. A 327 will be 10:1.
We beat it handily. Mid-lift flow is better. Exhaust flow is way better. The bigger deal is we achieve it with a 175cc runner instead of 210cc. It's a very high-velocity port. We also have standard port locations instead of raised with the fast burns. Independent flow tests of the GM Fast burns hover around:
Thanks, sounds like an excellent value. Better performance at a lower price.
Yes sir, we think so as well. Price is $740 ea. with guideplates and studs with the hydraulic roller spring package. Here's a page out of our catalog with all the specs.
Folks, we want to share some of our initial dyno testing on these heads. This was on a Chevrolet Performance 350/290 horsepower shortblock, the DHC 175 heads, and our street burner dual-plane.
The original crate engine has some pretty sorrowful 8.1:1 compression with 76cc heads. Putting the 60cc chambers on bumped that up to 9.6:1. Two cams were used.
The Summit SUM-1105 hydraulic flat tappet is a 224/234 duration, 114 Lobe Separation, and .466/.487 lift cam. This is comparable to the L79 cam at 221 degrees of duration, 114 L/S and .447 lift. Also comparable to the L46 cam at 222 degrees, 114 L/S and .450/.460 lift. It produced 398 horsepower and 388 ft./lbs. of torque.
Next up was the TFS-31402001. This is a hydraulic roller with 230/234 Duration, 110 Lobe Separation. .528/.539 lift. With this cam, the engine produced 430 horsepower and 400 ft./lbs.
Both cams, compression, and short block are pretty mild, durable and very comparable to what most people have. There are some dyno tests for the 350/290 factory crate engine with a similar cam produces. For now, here's a quick testing video.
This looks like a really great product. Wish I hadn't already just built my 355ci. I will keep it in mind for next time I decide to rip into my engine for more power.
Folks, we want to share some of our initial dyno testing on these heads. This was on a Chevrolet Performance 350/290 horsepower shortblock, the DHC 175 heads, and our street burner dual-plane.
The original crate engine has some pretty sorrowful 8.1:1 compression with 76cc heads. Putting the 60cc chambers on bumped that up to 9.6:1. Two cams were used.
The Summit SUM-1105 hydraulic flat tappet is a 224/234 duration, 114 Lobe Separation, and .466/.487 lift cam. This is comparable to the L79 cam at 221 degrees of duration, 114 L/S and .447 lift. Also comparable to the L46 cam at 222 degrees, 114 L/S and .450/.460 lift. It produced 398 horsepower and 388 ft./lbs. of torque.
Next up was the TFS-31402001. This is a hydraulic roller with 230/234 Duration, 110 Lobe Separation. .528/.539 lift. With this cam, the engine produced 430 horsepower and 400 ft./lbs.
Both cams, compression, and short block are pretty mild, durable and very comparable to what most people have. There are some dyno tests for the 350/290 factory crate engine with a similar cam produces. For now, here's a quick testing video.
Thanks for the input. I now have a question on the valve springs.
I’m looking at the specs on the 1.46” valve springs and am a little confused. The TFS-16315-16 springs have one set of specs listed with the DHC-175 heads, but different specs when installed on different heads or bought individually. Can you tell me what the actual spring rate for these springs is, and what the actual installed height and tensions are as installed on the DHC-175? The math for tensions listed on the literature for these heads just doesn’t work out.
I’m guessing the installed height is 1.85” instead of the 1.95” listed. That works out with the 420lb rate listed. But not with the 438lb rate listed when buying the springs separately.
The specs are critical to me for deciding on whether to use the Comp Magnum or Pro Magnum rockers.
Do the heads have a raised valve cover lip? I'd like to know if I can run stock LT-1/L-82 with 1.6:1 roller-rockers without needing an adaptor. Thanks!
Any luck with those new heads I very interested in seeing how they perform? How are people installing the heads ? Stock or a little port work for the larger sbc’s in the 383-406 range. I am thinking of buying them bare then have a little port work and a 2.05 valve for my HR 406. Thanks jeff
I am going to use the TF DHC 175 heads on my original 64 327 block. Aiming for about 400 HP on a 10.5 compression motor with maybe the Comp 280 H cam, Edelbrock intake with Holley 750. Quality headers will replace the 65 sidepipes. These heads make some good number out of the box.
I would like to buy these cylinder heads for my L82 engine but I have a choice to make : 0.540 max valve lift or 0.600 max valve lift for the best performance ?
I would like to buy these cylinder heads for my L82 engine but I have a choice to make : 0.540 max valve lift or 0.600 max valve lift for the best performance ?
10-19-2017, 03:22 PM
New "Vintage" Trick Flow heads
