The 18-degree Small Block Chevy (SBC) piston designs are crafted to optimize combustion efficiency and high-rpm performance. This guide highlights select Speed Pro pistons that fit common 5.7L 350 builds, with focus on coated skirts, ring compatibility, and bore options. Each product below is evaluated for compatibility with non-Vortec 1962-1990 SBC engines and standard bore sizes. Use this overview to compare bore options and features for your engine project.
| Product | Bore Options | Notes |
|---|---|---|
| Speed Pro H345DCP 350 Small Block Chevy SBC Flat Top Pistons Coated Piston 5.7″ 4.00″ Bore | 4.00″ | Coated skirts; pins included; flat top with 4 valve relief |
| Speed Pro H345DCP 350 Small Block Chevy SBC Flat Top Pistons Coated Piston 5.7″ (.030″ or 4.030″ Bore) | 4.030″ | Over size option; requires cart selection |
| Speed Pro H345DCP 350 Small Block Chevy SBC Flat Top Pistons Coated Piston 5.7″ (.060″ Bore) | 4.060″ | Over size option; coated skirt; pins included |
| Speed Pro H345DCP 350 Small Block Chevy SBC Flat Top Pistons Coated Piston 5.7″ (.040″ Bore) | 4.040″ | Over size option; pistons and pins included; coated skirts |
| Speed Pro H345DCP 350 Small Block Chevy SBC Flat Top Pistons Coated Piston 5.7″ (.060″ or 4.060″ Bore) | 4.060″ | Coated skirts; pins included; over size selectable |
Speed Pro H345DCP 350 Small Block Chevy Flat Top Pistons 5.7″ 4.00″ Bore
These Speed Pro flat-top pistons are designed for 1968-85 SBC 5.7L 350 engines with a standard 4.00″ bore. They feature coated skirts for reduced wear and pins included for installation. The design includes a 4-valve relief on the piston crown, optimizing combustion efficiency in non-Vortec early blocks. Suitable for standard bore builds without over-sizing. Rings are not included, so plan to pair with your preferred ring set.
Speed Pro H345DCP 350 SBC Flat Top Piston 4.030″ Over Size
For engines bored +0.030″, these flat-top Speed Pro pistons come as a replacement option for 1967-1990 Chevy 350s with a 4.030″ bore. The kit includes piston pins and a coated skirt for wear resistance. Ensure your cart reflects the correct over-size requirement before checkout, as these are not standard bore pistons. Compatible with small-block Chevy 350 builds seeking a mild over-bore upgrade.
Speed Pro H345DCP 350 4.060″ Over Size Piston
These pistons are designed for an over-size bore of 4.060″ and are part of the 18-degree SBC family. They include coated skirts and pins, and are suitable for engines bored +0.060″ over. Piston rings are not included, so consider a compatible ring set. This option is ideal for dedicated performance builds requiring a larger bore with preserved piston stability at high RPM.
Speed Pro H345DCP 350 4.040″ Over Size Piston
This option provides a 4.040″ bore with flat-top piston design and coated skirts. It includes piston pins but no rings, aligning with other Speed Pro 18-degree SBC piston offerings. Suitable for builds requiring a standard 4.040″ bore with corrosion-resistant coatings for long-term wear reduction. Match with a compatible ring set for a complete assembly.
Speed Pro H345DCP 350 4.000″ Bore, Standard Size
Standard bore option for the 18-degree SBC 350, the H345DCP configuration is a flat-top piston with 4 valve reliefs and coated skirts. Piston only, no rings, and pins included. This selection supports original 4.000″ boring measurements and is ideal for rebuilding a classic early Chevy 350 with modern flat-top geometry for improved compression and efficiency.
Buying Guide: Key Purchase Considerations
When choosing 18-degree SBC pistons, consider the following factors to ensure compatibility and performance for your build:
- Bore Size and Over Size: Confirm your engine’s current bore and the degree of over-sizing required. Over-size options require proper cart selection and may affect compression ratio.
- Ring Compatibility: Some piston sets ship without rings. Plan to select an appropriate ring pack that matches your piston and engine specifications.
- Coated Skirts: Pistons with coated skirts reduce wear during break-in and high-RPM operation, beneficial for performance-oriented builds.
- Pins Included: Ensure the piston kit includes wrist pins and whether locking features are required for your setup.
- Valve Relief Design: The 4-valve relief design on these pistons supports efficient clearance for the valves, reducing interference in certain cam profiles.
- Block Type and Era: These pistons target non-Vortec 1962-1990 SBC blocks commonly found in classic Chevy builds; verify compatibility with your specific engine family.
- Ringing and Assembly: Follow proper ring gap alignment and piston ring orientation to avoid scuffing and oil blow-by at high RPMs.
Other considerations include choosing between standard flat-top designs and elevated over-size bore options, assessing the intended use (daily driver vs. high-RPM race), and ensuring your forged or cast piston choice aligns with your crank geometry and cylinder wall finish. Consulting your engine builder or referencing the vehicle’s service manual can help confirm the best bore and piston combination for your performance goals.