How to Make 327 From a 350 CID Block

The Chevrolet 350 cubic-inch, small-block V-8 engine is arguably the most popular high-performance engine ever made, having been introduced in 1967 and based on the popular, high-revving 327 cubic-inch engine. The 350 and 327 have the same bore and rod length. The increase in displacement was obtained by increasing the 327's stroke of 3.25 inches to 3.48 inches, with the longer stroke enabling the 350 to produce more torque at a lower RPM.

Instructions

1

Verify whether you have a large or small-journal block. The Chevrolet 350 engines produced from 1969 onward have large-journal blocks, but the 350s made in 1967 and 1968 have small-journal blocks. This information is essential for you to know to get the right crankshaft, as there are large- and small-journal crankshafts that correspond to the blocks.

2

Verify that you have the correct 327 crankshaft. The 327s also come in large- or small-journal versions, with the 327 engines from 1962 to 1967 being small-journal and those in 1968 and 1969 being large-journal. The small-journal crankshafts have 2.3-inch main bearing journals and large-journal crankshafts have 2.45-inch main bearing journals. This applies to both the 350 and 327 crankshafts.

3

Install main bearings in the block and bearing caps. Install the correct 327 crankshaft in the main bearings in the 350 block. Install the bearing caps on the block. Install the bolts and use a torque wrench and socket to torque the bolts to the specification for your engine. You can use the connecting rods and pistons from the 350, as they are interchangeable with the 327, but please note that the crankshaft is the only part that must be changed.