Budget Mopar 440 Builds Big Torque on a Budget

Despite contemporary thinking, not all engine builds are mega-inch, mega-buck projects that, in reality, have very limited real-world application… except for possible bragging rights at the local gearhead gatherings. In truth, the vast majority of street-oriented engine builds are focused primarily on rock-solid reliability with a mild increase in performance and an eye towards an… The post Budget Mopar 440 Builds Big Torque on a Budget appeared first on The Online Automotive Marketplace.

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Dec 1, 2024 - 22:24

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Budget Mopar 440 Builds Big Torque on a Budget

Despite contemporary thinking, not all engine builds are mega-inch, mega-buck projects that, in reality, have very limited real-world application… except for possible bragging rights at the local gearhead gatherings. In truth, the vast majority of street-oriented engine builds are focused primarily on rock-solid reliability with a mild increase in performance and an eye towards an affordable budget.

We’ll admit that we, too, are regularly enamored with big displacement and astronomical horsepower numbers. The builds are exciting and fun to follow, but that simply isn’t the world most of us live in. So, it’s almost a relief when, every once in a while, we witness a rebuild that won’t twist the dyno to the moon or stretch the budget to mirror the national deficit.

Recently, we had the opportunity to follow along as our friends at Tommy’s Auto Machine in Springfield, Tennessee, took on a Mopar 440 build that reflected an approach to engine construction many of us can relate to and easily emulate.

Chrysler’s 440 is part of its RB-series of engines, which evolved from the B-series of V-8s that was first introduced in 1958. The RB (said to have stood for “raised B”) was a taller-deck version of the B-series. Raising the deck height of the block from the B-series’ 9.98 inches to 10.725 inches enabled a longer stroke, making way for the RB engines to eventually displace 440 cubic inches in original equipment form. And, as we all learned early on, “There’s no substitute for cubic inches.” So, it’s not altogether surprising that even the most pedestrian 440 can be coaxed to reasonable levels of performance, given the proper combination of parts administered in the appropriate dosage.

This ’70s-vintage 440 block provides the foundation for this road-going torque monster. Money spent on meticulous prep will pay dividends down the road, and included align honing the mains, decking to square the block and match the crank centerline, a .030-inch overbore, and honing with a deck plate.

So, what we’re following along here is a high-torque, low-budget rebuild of a .030-inch overbored 440, capable of running on anything dispensed from a typical gas station’s pump. The goal is to plant it in a ’69 Charger that can be used for effortless cruising around town as well as cross-country excursions, where some high-altitude areas’ octane ratings can dip as low as 85.

To accomplish this, a compression ratio of about 8.5:1 (or thereabouts) is compulsory, and as with any high-performance engine plan, careful calculations were made to ensure the correct components were selected for the engine package.

Since this 440 is nearly a “stock” rebuild, requiring nothing more than a solid foundation from which to begin, we started with a ’70-dated block, plucked from a rusty stockpile of similar cores. The block also yielded a good steel crank, while the rods and pistons were tossed in favor of a set of Six Pack rods and Speed Pro .030-over L2266F pistons. Using the beefy Six Pack rods added a measure of reliability and longevity, although they also required adding considerable weight to the crank to maintain the 440’s internal balance.

While the Six Pack rods might have been a bit of overkill for this application, the forged pistons are flat tops that help meet our compression requirements. They sit .090-inch in the hole, which may be good for achieving the low compression ratio we are looking for, but they have a quench area that’s notably less than ideal, making them a poor choice for building power.

Granted, the B and RB engines are certainly capable of generating ample horsepower, but they are not without their shortcomings. Port sizes and shapes on the iron OE heads are barely adequate to feed even a conservatively built, large-displacement engine like the 440, and the valve sizes—at 2.08-/1.74-inch—do nothing to alleviate the breathing bottleneck.

The Hastings rings feature a moly-faced top and a cast second ring; both were gapped at .022 inches.

As you’ve likely surmised, the RB’s OE-specs yield a combination that’s capable of generating prodigious bottom-end torque, but the inherent restrictions come into full play at anything approaching 4,500 rpm or more, even with more robust cam timing. Anybody serious about putting a big move on the dyno with an RB engine would do well to give it a little “breathing room,” and investigate the many aftermarket cylinder-head options.

The heads we’re using are 1977-dated, “452” castings, likely snagged off a motorhome engine. They were an easy choice, largely because they are inexpensive, widely available, and feature open combustion chambers with hardened valve seats. Considering our endgame, they’re an excellent choice to help keep the compression ratio down and torque output up.

In order to build a little cylinder pressure and boost low-rpm power, a fairly conservative hydraulic, flat tappet cam from Comp was chosen; it moves the valves to the tune of 224/224 degrees at .050-inch lift and bumps them .470/.470-inch off their seats. The lobe separation angle (LSA) is 110 degrees, which will help promote low-speed torque, and should provide a noticeably muscular idle that’s compatible with a stock converter, while still generating sufficient vacuum for power brakes and other accessories.

On the induction side, maintaining budget constraints and original appearance was important, so the engine was fitted with an original cast-iron intake manifold and topped with a rebuilt, original-style Carter AVS carb. Stock stamped rocker covers were also pressed into service to further the factory theme, and the entire engine was slathered in Mopar Orange.

Despite the depth of the block’s main skirts, a full-length windage tray goes in next to help keep the oil from wrapping around the crank and robbing power.

Already we can hear the horsepower-hungry masses screaming their dissent. For those power mongers, this engine combination would be scoffed at mercilessly. They’d argue that the parts combination is far from optimal. And we agree. But before you lose your mind, don’t lose sight of the original intent of this engine: It’s not about building maximum horsepower. Besides, informed engine junkies know that torque is what moves mass off the line and increases forward momentum, while horsepower gives it speed at the top end. We’re not building a race engine here; ours is destined to deliver gobs of rock-solid reliable torque, and to put it out right in the range where most cars are driven.

We ran the parts combination past our pal Kevin Shaw, who is editor of the Mopar Connection online magazine and its YouTube channel, to gather from his expertise. He agreed that while the component combination was far from optimal, it was appropriate in the context of application. “Power output?” Shaw wondered aloud. “I’d say you would be doing good to crank out about 300 horsepower. Anything over that would be exceptional.” Considering the source, his estimate was duly noted.

So, with the basic engine package laid out, let’s look at how it all went together and finish things up with a dyno session to see if Kevin’s prediction hit the target. Spoiler alert: we were pleasantly surprised and hope you will be too. Check it out!

An adjustable pushrod is used to set the manufacturer’s recommended lifter preload and to check valvetrain geometry. The process determines the correct pushrod length for the application. We ended up tossing the stock 9.315-inch pieces and ordering a shorter set with each 9.250 inches long.

Legacy Components

Properly processing the airflow in and out of an engine is crucial to making good power, and even with enhanced cam timing, that responsibility falls directly on the cylinder heads. The “452” castings here are far from anything special, but a little help can go a long way towards optimizing their capabilities. Good prep and good parts are used to help make that happen.

Ferrea stainless valves complement airflow with undercut, swirl-polished stems, and a bump in intake valve size from 2.08- to 2.14-inch while exhaust valve size remained the same at 1.74-inch.

Dyno Day

The only real way to test whether or not your efforts have been worthwhile is to strap the engine to the dyno and pull the levers. After our pal Kevin Shaw was apprised of the 440’s componentry, and he’d predicted that anything over 300 horsepower “would be exceptional,” we approached the dyno session with a throttled enthusiasm. But the big Mopar responded with surprising confidence and it eclipsed Shaw’s prediction by 73.5 horsepower at 5,200 rpm.

Of course, we weren’t looking for big power numbers anyway, and the engine’s ability to generate gobs of low-end grunt certainly grabbed our attention. Still, both ends of the equation are respectable, and the 440 will easily fulfill the task it was built for. Check the numbers for yourself.