ATTENTION: Valve Spring Warning for All Packages

On all complete assembly packages, it is very possible that the valve springs are not correct for your camshaft. All valve springs should be checked for compatibility to your camshaft. Severe wear of valve train components and severe engine damage could result from failure to do this. Check spring requirements before heads are installed on the engine. If in doubt please contact your camshaft manufacturer or USA Performance Parts. We do carry optional springs for all of your needs.

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Dart Big Block Chevy PRO1 CNC Ported Cylinder Heads, Assembly, pair

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Dart PRO1 CNC ported heads are available with 335cc & 355cc intake runners. 335cc heads fit 500 - 565 cid, the 355cc heads fit 540 - 632 cid. We applied the airflow technology developed in our championship-winning Pro Stock engine program to produce these state-of-the-art heads. Every intake port, every exhaust runner, every valve bowl, and every combustion chamber is 100% CNC machined on special dedicated PRO 1 castings.
Dart PRO 1 CNC heads are professional quality competition cylinder heads. We sleeve the head bolt columns between the intake ports to maximize the cross-sectional area at a critical point in the flow path. The high-velocity raised exhaust ports use Pro Stock airflow concepts that dramatically improve cylinder scavenging and the engine's ability to accelerate quickly. Multi-angle intake valve seats direct the air-fuel mixture into the chamber like an airfoil, reducing turbulence and preventing fuel separation. Fully radiused exhaust seats provide the smoothest possible transition into the ports for hot exhaust gases. Improved cylinder scavenging allows more fuel and air to be burned on the next power stroke. 121cc fast burn combustion chambers.

335cc & 355cc rectangular intake ports
121 cc chambers
2.300 x 1.880 stainless valves
Titanium retainers
10 deg locks
A6 assemblies - dual springs 1.625 OD, 250lbs @ 2.000 install height (.800 in. max lift)
A7 assemblies - dual prings 1.640 OD, 250lbs @ 2.000 installed height (.850 in. max lift)
A9 assemblies - triple springs 1.650 OD, 338 lbs @ 2.100 install height (.900 in. max lift)
We Specialize in Custom Assemblies with Upgraded Springs, Valves & Retainers

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For BBC PRO1 CNC TOP END KITS click here

Dart Big Block Chevy PRO1 CNC Ported Cylinder Heads, Assembly, pair

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Part Number Description Port Vol. Int/Exh Valves Spring Dia. Max Lift Spring Type Price In stock Purchase
19474030-A6 Assem, pr 335cc 2.300/1.880 1.625D .800 Dual $3,198.00 Yes
19474030-A7 Assem, pr 335cc 2.300/1.880 1.640D .850 Dual $3,249.00 Yes
19474030-A9 Assem, pr 335cc 2.300/1.880 1.650T .900 Triple $3,398.00 Yes
19574030-A6 Assem, pr 355cc 2.300/1.880 1.625D .800 Dual $3,198.00 Yes
19574030-A7 Assem, pr 355cc 2.300/1.880 1.640D .850 Dual $3,249.00 Yes
19574030-A9 Assem, pr 355cc 2.300/1.880 1.650T .900 Triple $3,398.00 Yes

For Technical Information please click here.

To view this product's Specifications page, please click here.

This product was added to our catalog on Friday 18 March, 2005.

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