318CI SMALL-BLOCK CHRYSLER

CARNAGE WORKSHOP, MELBOURNE, VICTORIA

WHEN it comes to Mopar smallblocks, the 318ci V8 is the forgotten child of the family. You know – the one that is wellbehaved, does all the chores and gets good grades but is always overshadowed by their bigger and smaller siblings. It’s an engine that has powered just about everything in the Chrysler range, and in factory form it was rated at anywhere between 140 and 230hp.

Despite the relatively low power output, the 318 does have a reputation for reliability, and it was made in massive numbers, too, with a production lifespan that stretched from 1967 through to 1991. There are literally millions of them out there, and with the larger 340 and 360 engines becoming harder and more expensive to find, the 318 has developed a loyal following among Mopar fans as they look to the smaller engine to power their street machines.

Which brings us to this particular mill. We found this 1982 318 sitting on a pallet in the back of a speed shop warehouse, and the price was right. It was a short-block that had been rebuilt 60thouover, and I thought it was the perfect budget engine to repower one of my Mopar projects. But then it got bolted to an engine stand and forgotten about for 10 years.

Fast-forward to earlier this year at the Carnage workshop, where my late father’s VE Valiant ute was sitting sadly in the corner. With Mopar Sunday then fast approaching, it seemed like the perfect opportunity to get the ute back on the road with some V8 grunt – something that Dad always talked about but never got around to doing.

After seeing a few 400hp builds in the US magazines, I figured it would be nice to do something similar here, but when I looked into those builds, I noticed that they always seemed to either use specific factory heads that were never available in Australia or aftermarket heads that were equally hard to find. I wanted to use parts that were readily obtainable, and what’s easier to get than Edelbrock gear?

So we told Edelbrock our plans and the company sent out one of its Performer RPM Top Kits (PN#2049). It’s a dyno-proven kit that includes an RPM Air-gap intake manifold, Performer RPM cylinder heads, 234/244 hydraulic cam and lifters, timing chain, complete head and intake bolt kits, and an Edelbrock gasket set. On a 9.5:1-compression 340ci small-block, Edelbrock rates the package at 417hp, so we were hoping for similar numbers from our higher-comp 318 Mopar.

However, getting those compression numbers up is a little harder than it sounds. The pistons that came with our 318 were 76thou down the bore at TDC, yielding around 8.2:1 comp, which meant we would either have to deck the block a lot to improve the comp, or buy new pistons. We went for the second option, purchasing some KB hypereutectics (PN#399) that were going to give us all the compression we needed.

Unfortunately, they fouled on the chambers of our Edelbrock heads. So we shipped the whole lot off to Top Torque Engines so they could make the necessary adjustments to the pistons and bores, along with a bottom-end engine balance.

The compression ratio ended up around 10.5:1, and with the 60thou overbore, it puts the capacity a smidge under 328ci. So with extra comp but slightly less capacity than Edelbrock’s test-bed 340, we feel it should about equal the 340’s output and make somewhere around 400hp.

We’ll know one way or the other by the time you read this; either way, it should be a stout little engine.