{"product_id":"texas-speed-steel-adjustable-1-8-ratio-roller-rocker-package-tsp-1-8rr-adj-cath","title":"Texas Speed Steel Adjustable 1.8 Ratio Roller Rocker Package — LS1, LS6 \u0026 5.3L Cathedral-Port Heads | TSP-1.8RR-ADJ-CATH","description":"\u003cp\u003eThe Texas Speed Steel Adjustable Cathedral 1.8 Ratio Roller Rocker Package is a complete set of adjustable roller rockers for LS engines running cathedral-port cylinder heads. The rockers are machined from 17-4 stainless steel, use a swedged roller pin for durability and mount to the factory rocker pedestals, so they install without a shaft-mount conversion.\u003c\/p\u003e\u003cp\u003eThe 1.8 ratio raises valve lift and effective duration over the stock 1.7 ratio for a given camshaft lobe, and the adjusters allow lash to be set, which is why Texas Speed recommends this package for solid roller camshaft applications. The rockers are Spintron tested in-house. Stock valve covers are not compatible with the taller adjustable design, so TSP tall valve covers are required, and minor cylinder head trimming may be needed depending on casting variation.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eRocker ratio: 1.8:1\u003c\/li\u003e\n\u003cli\u003eType: Adjustable roller rocker arms, bolt to factory pedestals\u003c\/li\u003e\n\u003cli\u003eMaterial: 17-4 stainless steel\u003c\/li\u003e\n\u003cli\u003eRoller pin: Swedged for improved durability\u003c\/li\u003e\n\u003cli\u003eFitment: GM LS 5.3L cathedral-port cylinder heads, LS1 and LS6\u003c\/li\u003e\n\u003cli\u003eRecommended use: Solid roller camshaft applications\u003c\/li\u003e\n\u003cli\u003eTesting: Spintron tested in-house by Texas Speed\u003c\/li\u003e\n\u003cli\u003eQuantity: Sold as a complete set\u003c\/li\u003e\n\u003cli\u003eValve covers: TSP tall valve covers required; stock covers not compatible\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Requires TSP tall valve covers; stock valve covers are not compatible.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Minor cylinder head trimming may be required depending on casting variation.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e Verify valve cover and cylinder head clearance before installation.\u003c\/p\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\u003ch5\u003eWhich cylinder heads do the Texas Speed 1.8 adjustable cathedral rockers fit?\u003c\/h5\u003e\u003cp\u003eTexas Speed lists this adjustable 1.8 ratio roller rocker package for GM LS cathedral-port cylinder heads, including LS1, LS6 and 5.3L cathedral-port heads, mounting to the factory rocker pedestals.\u003c\/p\u003e\u003ch5\u003eWhat does a 1.8 rocker ratio do compared with the stock 1.7?\u003c\/h5\u003e\u003cp\u003eA 1.8 ratio multiplies cam lobe lift by 1.8 instead of 1.7, so valve lift and effective duration increase for the same camshaft. Spring travel, retainer-to-seal and piston-to-valve clearance should be rechecked with the higher ratio.\u003c\/p\u003e\u003ch5\u003eDo these rockers require special valve covers?\u003c\/h5\u003e\u003cp\u003eYes. Texas Speed requires its TSP tall valve covers with this adjustable rocker package, since stock valve covers are not compatible with the taller adjuster design.\u003c\/p\u003e\u003ch5\u003eAre the 1.8 adjustable rockers meant for solid roller cams?\u003c\/h5\u003e\u003cp\u003eTexas Speed recommends them for solid roller camshaft applications, where the adjuster is used to set valve lash. They are built from 17-4 stainless steel with a swedged roller pin and are Spintron tested in-house.\u003c\/p\u003e\u003ch5\u003eWill I need to modify the cylinder heads?\u003c\/h5\u003e\u003cp\u003eMinor cylinder head trimming may be required depending on casting variation. Texas Speed advises checking valve cover and cylinder head clearance before installation.\u003c\/p\u003e\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Which cylinder heads do the Texas Speed 1.8 adjustable cathedral rockers fit?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Texas Speed lists this adjustable 1.8 ratio roller rocker package for GM LS cathedral-port cylinder heads, including LS1, LS6 and 5.3L cathedral-port heads, mounting to the factory rocker pedestals.\"}}, {\"@type\": \"Question\", \"name\": \"What does a 1.8 rocker ratio do compared with the stock 1.7?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"A 1.8 ratio multiplies cam lobe lift by 1.8 instead of 1.7, so valve lift and effective duration increase for the same camshaft. 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