Coast High Performance 347ci Stroker - Get 347 Cubes From Your 302

Our subject block was an '84-'85 5.0L roller block that hadn't been drilled and tapped for the roller lifter spider.

It had to be drilled and tapped for spider bolts. Block cleanup is mandatory after this step.

What makes a Coast High Performance engine an extraordinary value is attention to detail. These aren't mass-produced crate engines-they're custom-built one at a time. All machined surfaces are checked and rechecked prior to assembly.

If you have the option, we suggest you step up to a late-model 5.0L block that incorporates the 360-degree oil seal. This is as leakproof as it gets and beats the older half-seals found in the 289 and 302.

Coast uses Clevite bearings, which are able to withstand a lot of punishment.

We're using a mid-'80s 5.0L block for our 347 build. Everything has been machined, and the block is ready for checking and buildup.

The main caps have been torqued to specifications, which allows engine builder Mark Jeffrey to check each main bearing.

Coast engines receive an abundance of assembly lube for a slippery start-up. No one wants the experience of dry bearings during a start-up. Jeffrey suggests priming the oiling system before the first fire-up.

The rear main seal saddle receives a mild dressing of sealer before the crank is installed. This makes for a foolproof, leakproof seal.

This is the custom-made, specially ground, cast-iron crankshaft that's 347-specific.

Rods are torqued to specs and checked with a micrometer as shown. Close attention to detail is critical here.

The 347 Street Fighter has free-floating piston pins, which eliminate any binding and improve flexibility.