If there's one thing Mopar guys all have in common, it's a love of history. We all remember the days when muscle cars ruled the roads, instead of the current regime of under-powered, jelly-bean looking rides that are thrust upon us now. We remember the obnoxious colors, the loud exhausts, and the time when a threat of not being able to get leaded fuel with a 105 octane rating wasn't even a thought. Those are what many consider the "good ole days."
But many of us seem to selectively forget that our beloved cars of the time never idled very well, were grossly over-cammed, and drank enough fuel to keep a small city driving today. But that's the great thing about memories; they're always about the cool stuff.
Before you ever begin to assemble an engine, it's a good idea to chase all of the threads
Back in the March '10 issue, my ramblings in my Off the Line column hinted about going back to the good ole days. To me, driving an over-cammed engine with no vacuum that won't idle under 1,200 rpm is still cool. While not being able to buy fuel at the local gas station may be a problem, it does add a certain amount to the coolness factor of the car. Anyway, Project Valiant Effort was due for a face lift and personality change, and in the April '10 issue, we handled the face lift by adding a set of Holeshot wheels and Mickey Thompson tires. Now it's time to address the personality.
The Valiant has been a fun car with its pump-gas friendly 360, and the engine is more than adequate when one wants to play. However, we want to take the demeanor of our Valiant from simple cruiser to stupidly cool cruiser. To accomplish this, we looked back to the good ole days and thought about the cars we remember that were running big compression, over carburetion, and cams with enough lift and duration to snap a standard valvespring. Sure, we all know it's overkill, but it left enough of an impression to keep the memory alive, so here we are. We want to relive our youth. We want to remember a time when if we had to choose between a new camshaft and taking our girl to the Prom, we couldn't wait to show our buddies our new bumpstick.
When installing the oil galley plugs, don't forget about the one on the back of the lifter
There are a couple of different ways we could approach this engine build. One way would be to try and make every last bit of horsepower possible by using trick parts, and spending a lot of time refining every aspect of the parts and assembly. Lately though, we have been getting a substantial amount of letters from guys who just can't afford all the trick parts and machining and want to see us start doing stuff without getting carried away. So for this build, we're simply going to do only the machining that is required, and then bolt this thing together. In the end, the engine may not make as much power as it could, but with the right parts selection, power will still be respectable-we hope.
....It's visible from the distributor hole if you're not sure of the location.
Knowing that this engine's planned activities will stretch the limits of an "old," seasoned engine block, we felt it necessary to upgrade and started with a Mopar Performance 340 resto block PN 5007552. Yes, using a Mopar resto block will add to the cost, but this non-Siamese bore block (Siamese version is available PN 5153478) is machined to work with all 340 production components, is a brand-new casting made from high-nickel cast iron for added strength (not a thin wall casting), has four-bolt main bearing caps, and a 340 journal size. It also has a thicker pan rail and webbing (like the '70 340 T/A version), a thicker deck surface, and thicker-bore walls in major and minor thrust directions. The block is rough bored at 3.900-inches to allow various bore sizes, from 3.910-inches to 4.080-inches (finish bore and honing required). Deck height is approximately 9.600-inches. The new resto block includes the original 340 production-casting part number with an "M" added at the end to identify the Mopar 340 block. We happened to find a block that had some unusual cylinder scarring and got a good deal on it. The scoring wasn't bad, and when we took it to our machinist (Auto Performance Engines), the bores cleaned up nicely at 4.060-it was 4.040 when we got it.
When we first started to install our Milodon main studs, unbeknownst to us, we would run i
After the Clevite bearings and crankshaft are installed, torque the caps.
Our rings are Total Seal's with a gapless second ring. All ring gaps are set to the piston
With the rings file-fit, and the Clevite bearings lubed, "beat" the piston and rod assembl
The problem we ran into with the Milodon main studs was revealed when we tried to install
Before we installed the pump, we filled it with a quality break-in lube. Now when we prime