Essential Machine Work (almost always needed):
* Block Deck Surface: This is crucial to ensure a perfectly flat surface for the cylinder head gasket. Warpage can lead to leaks and inconsistent combustion.
* Cylinder Boring/Honing: Increasing the bore from the stock 350 to accommodate the 355's larger displacement requires boring. Honing follows boring to create a cross-hatched surface for proper ring seating. This is essential for proper compression and sealing.
* Cylinder Head Milling (potentially): If using stock or used cylinder heads, milling them to a flat surface and to achieve the desired compression ratio is usually necessary. This also ensures a good seal with the block.
* Crankshaft Grinding (potentially): Depending on the condition of your crankshaft, it may need grinding to remove any imperfections or wear. This restores roundness and proper bearing clearances.
Potentially Needed Machine Work (depending on condition and build goals):
* Line Boring/Block Alignment: This ensures the main bearing bores are perfectly aligned to the crankshaft. It's usually recommended, especially for high-performance builds, to ensure optimal crankshaft support and reduce stress.
* Cam Bearing Boring: If installing a new camshaft, accurately boring the camshaft bearings is crucial for proper camshaft alignment and rotation.
* Connecting Rod Bearing Sizing/Fitting: While often handled by the builder, connecting rod journals may require sizing if using new or reconditioned rods.
* Valve Seat Work: If using existing cylinder heads, valve seats may need to be re-cut and ground to ensure a good seal, improve flow, and prevent leaks. This is more common with performance builds.
* Deck Plate Milling (for aftermarket blocks): Only relevant if using aftermarket blocks, it ensures a flat surface for the main bearing caps.
In short: At minimum, you'll need a machine shop capable of block deck surfacing, cylinder boring/honing, and potentially cylinder head milling. For a more robust and reliable build, especially for a performance-oriented 355, line boring, crankshaft grinding, and possibly cam bearing boring are strongly recommended. The valve seat work depends largely on the condition of the heads and your build goals.
