Planning or upgrading a 350 small block turbo setup? This guide highlights the best block-off plugs, speedometer solutions, and related turbo transmission accessories that fit TH350 era transmissions. Each product is chosen for reliability, compatibility with Turbo 350 applications, and ease of installation. The top picks below cater to different buyer needs, from clean cosmetic finishes to robust leak-proof seals. Use the quick reference table to compare key features at a glance.
| Product | Recommended For | Best Feature |
|---|---|---|
| AIRCMT TH350 Kickdown Cable Port Block-Off Plug Kit | Those removing the kickdown cable setup or restoring a clean engine bay | 6061 billet aluminum construction |
| Premium TH350 Kickdown Delete Plug Kit | Retail/restore projects needing a durable, leak-proof seal | 6061 aluminum with 304 stainless hardware |
| Nicpalintk Speedometer Block | Turbo 350 owners eliminating the speedometer port | CNC machined billet aluminum for durability |
| Vkinman TH350 Speedo Housing | Leaky speedometer housing corrections for TH350 | Precision CNC billet aluminum with extra O-ring |
| FBSCTMH TH350 Speedo Gear Housing Leak Stop Kit | Users needing a reliable seal kit for speedometer components | Stainless bolts and NBR/fluorine O-rings |
Below, each selected product is described with who it’s best for, why it was chosen, and a practical caution. All sections use clear, objective data to help you compare options quickly.
AIRCMT TH350 Kickdown Cable Port Block-Off Plug Kit
Best for builders removing the kickdown cable entirely or tidying the engine bay for turbo install. The kit is machined from 6061 billet aluminum, offering a solid, corrosion-resistant plug that fits TH350 kickdown cable ports. The stainless steel screw and O-ring help seal against oil leaks. Choose this if you want a clean, durable block-off with straightforward installation. Caution: verify port dimensions on your specific TH350 model to ensure a proper fit.
FBSCTMH TH350 Speedo Gear Housing Leak Stop Kit
Best for TH350 owners with oil leaks around the speedometer housing. This kit is designed for Turbo Hydra-matic TH350 / TH350C transmissions from 1969 onward and includes high-quality stainless bolts and seals. The included NBR and fluorine O-rings help create a long-lasting seal. Choose this if you want a practical repair kit that targets leaks specifically at the speedometer gear housing. Caution: assembly requires proper routing to avoid interfering with sensor alignment.
Nicpalintk Speedometer Block Off Tool
Best for Turbo 350 transmissions needing a precise speedometer port delete with a professional finish. CNC machined from billet aluminum, this block-off tool provides durable wear resistance and a clean appearance. It’s designed specifically for TH350 transmissions, making installation straightforward. Choose this if you want a dedicated port delete with a sealing O-ring. Caution: ensure compatibility with your drivetrain year and model to avoid fit issues.
Vkinman TH350 Speedo Housing with Extra O-Ring
Best for preventing leaks in speedometer housings on TH350 transmissions. This CNC machined billet aluminum block-off plug provides a precise fit and includes an extra O-ring and metal seal kit for enhanced longevity. Choose this option when you want a sleek, durable component that improves sealing and appearance. Caution: color finish is silver; if you’re matching a specific under-hood aesthetic, ensure it complements your setup.
Premium TH350 Kickdown Delete Plug Kit
Best for those seeking a high-grade, leak-proof kickdown delete solution. The kit uses dual premium materials: main plug from 6061 aviation aluminum with a fine CNC finish and a 304 stainless fastening screw. An upgraded rubber O-ring plus optional RTV silicone sealing result in a tight, all-around seal. Choose this if you prioritize a robust, long-lasting installation to prevent oil seepage and maintain a clean engine bay. Caution: installation may require careful torque to avoid over-tightening the plug.
Buying Guide: Key Purchase Considerations
- Transmission compatibility: Confirm TH350 or Turbo 350 applicability before ordering any block-off or speedometer-related part.
- Material and finish: Billet aluminum parts (6061) offer durability and corrosion resistance; stainless fasteners reduce rust risk.
- Seal quality: O-rings and seals should be fluorine or NBR-based for oil resistance and longevity.
- Ease of installation: Look for products with simple mounting hardware and precise fitment to minimize installation time.
- Aesthetic fit: Some components have a silver or raw aluminum finish; ensure it matches your engine bay appearance.
- Leak prevention: Prioritize solutions that include a robust sealing system and, where possible, an auxiliary RTV sealant recommendation.
Frequently Asked Questions
- What is a kickdown delete plug kit used for in a TH350?
– It seals the unused kickdown cable port after removing the kickdown assembly to prevent leaks and simplify the transmission area. - Are billet aluminum blocks durable for turbo installations?
– Yes. Billet aluminum blocks are known for strength, corrosion resistance, and precision fit, suitable for under-hood use. - Do these products affect transmission performance?
– They primarily affect sealing and port management. They do not alter core transmission performance but help prevent leaks and improve appearance. - Is an extra O-ring recommended for speedometer housings?
– An additional O-ring can improve sealing and longevity when installing a speedometer block or housing kit. - Which part is best for a leak-prone speedometer area?
– A kit that includes a full seal set (O-rings and gaskets) and a reliable housing block is recommended to mitigate leaks. - Can I use RTV silicone with these plugs?
– RTV silicone is often suggested as an extra sealant precaution, especially for the kickdown delete plug installation.