Last month, we kicked off the "Build Your First Engine" story with an overview of how to rework the short-block. In the process, we cheated a little bit by simply replacing the entire rotating assembly-crank, rods, pistons, balancer, and flexplate-with brand-new parts from Powerhouse rather than reconditioning the stock parts. Why? Because in today's world, it would have been a false economy to retain the stock 350 stuff when for a mere $879 we jumped from 350 to 383 cubes and got the reliability boost of all new parts with a Powerhouse stroker kit.
This month, with help from Pete Hillemeyer at JMS Racing Engines, we'll handle the cylinder heads. Yes, the aftermarket is full of exceptional deals when it comes to preassembled, ready-to-run, cast-iron and aluminum cylinder heads. And yes, we'll explore this awesome fact...next month. But for the purpose of showing you the steps required in the refurbishment of cylinder heads, we'll spiff up our original small-valve, 76cc, big-chamber truck heads.
Refurbishing iron heads may seem like a silly plan for some, but if you've got a rare musclecar like an original L79 Nova, Z/28, or Corvette, and you want to keep it matching-numbers, you'll want to know what's in store when you lug the heads to the machine shop. Also, while the low price of many aftermarket heads is tempting, plenty of hot rodders operate on shoestring budgets, so the checkbook-replacement strategy isn't an option. Beyond all that, the happy fact is that the vast majority of iron 350 head castings were born equal and all can deliver stout performance with just a little bit of love.
Next time, we'll put it all together and wing it out on the dyno. Plus we'll explore the cost-benefit ratio of reworked iron heads versus preassembled aftermarket replacements. Then we'll compare single-and dual-plane intake manifolds to see which is right for you. So until the final segment, let's dig in and get to work.
Before we spent a dime on...
Before we spent a dime on machine work, we had to be sure our heads weren't full of cracks or had any other problems that could quickly flip the cost-benefit equation upside down. It all began with a Magnaflux inspection to expose external fractures.
To detect internal cracks,...
To detect internal cracks, heads are clamped into the Axe Equipment pressure-test machine and compressed air is pumped into the coolant passages at 30 psi. That's nearly twice the pressure created in a typical cooling system. If they don't leak here, it's all good.