The Torquer V4 camshaft features a more aggressive intake lobe that requires a good double valve spring kit. For customers looking for a quality double valve spring kit, we recommend the PAC .660" double spring kits. The new more aggressive intake lobes & small changes to the camshaft design has allowed us to create more peak power while bringing power in earlier than the Torquer V2. With the Torquer V4 camshaft we typically recommend the customer have at least a 3000 rpm stall converter for automatic cars. Tuning will also be required in both automatic & manual applications.