440-inch Aftermarket LS Is a Street-Friendly Torque Machine

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When deciding on an engine build for a project, the key factor is how that car will be used. While a drag car might be all about top-end power with no cares spent on drivability, a street car will be the exact opposite. If your plan is a pro-touring car that will drive on the street yet be able to tackle road and autocross courses, then you need a mill that can do a little bit of everything well and have an abundance of low-end torque.

In our case we needed and engine for our 1968 Camaro project called Track Rat. We wanted gobs of low-end grunt to pull us out of tight corners and around pesky cones at lower speeds. Sure, we wanted top-end power for the straights, but we couldn’t sacrifice street manners since this wasn’t going to be a trailer queen.

We wanted to stay NA, so that meant our formula had to include added displacement. After crunching numbers we came up with a 440-inch (4.125-inch bore and 4.125-inch stroke) LS based around RHS’ aftermarket block.

With its raised cam and long sleeves, this block was built for stroking since RHS spent considerable effort reworking the internal dimensions to accommodate spinning cranks and flying rods. They also addressed oil control and incorporated features like motor plate race mounts for the hardcore crowd and provisions to easily add a dry sump oiling system. All in a package no bigger than your garden-variety GM LS engine. Sweet! For those that don’t mind the external dimensions bumping up a bit, RHS also offers a tall-deck version that is engineered to accept up to a 4.600-inch crank. Combine that with the RHS block’s maximum bore of 4.165, and you get the potential for 501 cubes (8.2L). On this build we’re shooting for the middle ground at 440 cubic inches (7.2 liters for those of you stuck in a metric-based country) with their standard deck block.

The RHS blocks are automotive works of art. Made using a Clean Cast Technology, and A357-T6 aluminum, they show up with an excellent finish. The blocks are dry-sump-ready with provisions for AN-12 feeds at the front and rear. Every block is CT scanned by RHS to save you hassles down the road. For extra strength all the threaded holes have rolled threads and the block came to us already deburred.

For additional strength RHS maximized the main cap surface area and incorporated large fillets from the cap to the cross bolts. All the billet main caps are doweled for stability, and the block ships from RHS with ARP main hardware.

Having more cubes means we could suck up a bigger cam without suffering any ill effects on the street. Still, we wanted to keep it smooth since this will primarily be a street car that sees the track and not the other way around. Given this, we went with a custom grind from Comp (PN 54-000-11) that had duration of 235/254, lift of 0.610/0.596, and an LSA of 113+4. In a smaller engine this would be a big cam, but in the 440 it should strike a nice balance.

The RHS block does require a proprietary cam thrust plate, but they are nice enough to include this bronze beauty with the block.

The Lunati Pro Series crank (PN 60841251) was so pretty it was a shame to hide it inside the engine. American machined from 4340 certified steel, this crank will easily handle the abuse we plan to heap upon it. The journal radii are ground to .140 inch, roundness of each journal is .0001 inch or less, and each rod journal incorporates a lightening hole to reduce inertia weight. RHS standard-deck blocks can handle a lot of stroke (up to 4.25-inch), but we opted for 4.125-inch as a balance between rpm and displacement.

The bigger the stroke, the more critical, and difficult, balancing becomes. For this we had the experts at Lunati balance the rotating kit, and here’s just some of the molybdenum (moly to its close friends) used to keep everything happy once the spinning starts.

Checking crank thrust is always a good idea, and Chris Pollock at Evod Garage in Escondido, California, made sure we were right on target. At first we had nearly zero thrust (it can be anywhere from 0.003 to 0.010 inch), but Chris was able to get us to 0.004 inch. On a manual car, it’s better to be on the tighter side.

The badass crank meant we needed equally badass rods. Lunati’s I-beam 4340 rods can take the abuse—and trust us that rods are subjected to a lot of stress, more than any other engine component. These 6.125-inch rods (PN JP6125-8) weighed in at 637 grams (rotating weight of 455 grams), and we opted to upgrade them to the stronger ARP 2000 rod bolts.

Buy sticking with a common bore size of 4.125 inches (same an LS7) we had a plethora of piston choices. We opted for a full set of Mahle forged slugs (PN LSX045125F08). The flat top design (with two valve reliefs) would get us right in the 10.9:1 compression range with the heads we chose. Like all Mahle pistons we use, these came fully coated with a dry phosphate to protect against ring micro-welding and galling on start up. They also had a Grafal anti-friction coating on the skirts.

Chris then went about the tedious but necessary task of file fitting the rings using his Summit Racing hand file. The rings used were the plasma moly rings included with the Mahle pistons.

And after messing with 16 wire locks our ringed pistons were mated to our Lunati rods. Notice the writing on the pistons? That’s because Chris matched each piston/ring combo with each cylinder. For bearings we went with Clevite for the rods and mains.

It was then time to slide the piston/rod assemblies into the RHS block using our ARP ring compressor (PN 900-1250). The RHS block’s Siamese-cast bore walls can go from 4.100 to 4.165 inches and have pressed-in spun-cast liners (5.87 inches for standard and 6.38 inches for tall decks). The blocks also incorporate improved bay-to-bay breathing compared to factory LS blocks.

With the rotating bits installed we could torque down all the APR hardware and double check that everything was just as it should be.

To keep it all timed properly we went with a Lunati keyway-adjustable billet timing set (PN 95536). The pre-stretched double-roller chain is more than strong enough, and the kit offers four degrees of advance or retard. The chain also had an extra link to accommodate the raised cam design of the RHS block.

Chris is very meticulous about how he installs water pumps. His trick is to take it apart and build it in place so he can use a feeler gauge to make sure it’s properly centered on the crank snout.

After adding our comp double-roller-ready front timing cover (PN 5495) and our honed ATI damper hub (PN 917083), our short block was officially done.

To keep the air flow feeding our hungry 440 we went with a pair of Brodix BP BR 3 LS3-style CNC ported heads (PN 1173700). These featured 280cc intake ports that are rated over 363 cfm. They also utilize a 15-degree valve angle with 71cc chambers and a 2.165/1.590 valve combination.

After putting the Fel-Pro PermaTorque MLS head gaskets in place we installed the Brodix heads using an ARP head stud kit (PN 234-4339).

When rpm is part of the plan you don’t want to skimp on lifters. For the 440 we went with Comp full-travel hydraulic roller lifters (PN 8957-16). These link-bar lifters are specified for aftermarket blocks like our RHS unit. They are lightweight and made from heat treated 52100 steel for better wear resistance.

When it comes to rockers it’s really hard to beat factory pieces. Sure, shaft rockers are cool, but when it comes to lightweight functionality the factory design is a great choice. Given this we contacted Ed Doyle over at CHE to build us a set of their bushed LS3 rocker arms. CHE takes the GM rocker arms, ditches the problem-prone needle bearings, and bushes them. According to Ed, “This has the added benefit of creating a stronger unit, with better load characteristics,and a rocker with a greater service life even underextreme conditions.” Having an LS rocker fail and blow debris through an engine sucks, so we’re more than happy to make this upgrade.

This engine is for our 1968 Camaro project called Track Rat. As the name implies we plan on hitting road tracks and autocross courses in it, so we need to have a robust oiling system. To clear our Chassisworks frame we opted for a Holley oil pan, but to keep the oil where it should be we went with this Improved Racing trap-door pan baffle offered though Holley specifically for their pans (PN 302-10).

After securing the baffle in the pan we bolted the Holley pan (PN 302-1) to the bottom of the RHS block using a Fel-Pro gasket and some of the stainless hardware from our ARP accessory bolt kit (PN 534-9605).

Flipping the RHS 440 back over we installed a pair of tall Holley LS valve covers (PN 241-121) along with a FAST 102mm LS3 intake, matching fuel rails (PN 146028B-KIT), eight FAST 50-pound fuel injectors (PN 30507-8), and the rest of our ATI damper. At this point it was time to haul the 440 over to Westech performance for a date with their Superflow 902 dyno.

Once on the dyno, we slapped on the MSD coils, matching plug wires, and bolted up a set of Hooker long tube headers. Our car will be running a throttle-by-wire unit, so we borrowed a FAST throttle body. After bolting on a Meziere electric water pump we were ready to fire up the 440 and run it through the break-in procedure using Lucas oil.

After some tuning on the Holley HP ECU we knocked down our best pull of 641 hp at 6,200 rpm and 596 lb-ft at 5,000 rpm. But this is about more than peak numbers. Notice that even though peak hp was at 6,200 rpm, the curve stayed nearly flat all the way to 7,000 rpm! Also notice that when we rolled into the pull at 3,600 rpm the 440 was already making around 540 lb-ft! We call that a recipe for a good time.

Of course we often get asked, “Yeah, but how does it do in the car?” Well, in this case, we could find out since this was installed into our Track Rat 1968 Camaro project. So with the engine installed, breathing through Holley/Hooker headers, along with a full exhaust, we strapped the Camaro to Westech Performance’s chassis dyno for some tuning.

Many things can change the “at wheel” power numbers of an engine that was run on an engine dyno. Drivetrain loss, rearend choice, and the size/design of the exhaust are all factors. For the 440 installed in our Track Rat Camaro we put 558 lb-ft and 559 hp to the tires. Peak power was much sooner on the chassis dyno but held steady through 6,200 rpm. But, it was the torque that got us all giddy. 450 lb-ft way down at 3,000 rpm with a flat curve past 5,200 rpm will make us need to reevaluate our rear tire budget. When it comes to torque there really is no replacement for displacement on a naturally aspirated mill.

Post time: May-26-2020

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