In Part 1 of our 540 cubic inch big block Chevy build, we covered prep of the Dart Big M block, balancing and installation of the Scat/ICON reciprocating assembly, and installing the COMP Cams solid roller camshaft and timing gear. All good stuff.

In Part 2, we continue the build with the oiling system; installing the Dart Pro 1 cylinder heads and Harland Sharp roller rocker arms; and a Dart rocker stud girdle. We also checked piston to valve clearance and measured for proper pushrod length.

In Part 3, we’ll wrap up our project with the installation of the induction and ignition systems, headers, and other parts like the harmonic damper and electric water pump. Then, we go to dyno and show you how powerful our 540 is. That’s good stuff, too.

If you’d like to see the other stories in this build series, check them out here:

Oil Pump & Pan

We chose a Melling high volume/high pressure oil pump for this build. The pump body is CNC machined from 6061-T6 billet aluminum and has an integral pickup screen to keep the pickup from loosening. Features include smoother oil flow and less internal drag as compared to conventional pumps; billet spur gears; a chromoly driveshaft with extended support; an adjustable pickup screen; and multiple pressure settings. Another very nice feature are machined stand-offs at the bottom of the pump body surrounding the screen area. They prevent smothering the screen in case the pan sump ever touches the pump.

using a flatedge to measure flatness on an engine
We chose a Melling high volume/high pressure oil pump for this build. The pump body is CNC-machined from 6061-T6 billet aluminum and has integral pickup screen to keep the pickup from loosening. It’s secured to the main cap with an ARP stud kit. With the gasket in place, we measured 0.350 inch clearance between the pickup and Moroso oil pan’s sump floor. (Image/Mike Mavrigian)

The Melling oil pump requires an oil pan with an eight inch deep sump. The pump includes a mounting stud and nut, but I opted to use an ARP pump stud as it features a female hex that is handy for installation or removal.

Suitable for street, drag or road race use, the Moroso steel oil pan has the required eight inch deep kickout sump and a sump capacity of 6.5 quarts. The pan can handle Stroker cranks up to a 4.250 inch stroke. Features include a trap door baffle system, windage tray and crank scraper; and a 1/4 inch NPT dipstick bung located on the right side of the pan.

windage tray & trapdoors in am engine oil pan
The seven quart Moroso Drag/Road Race oil pan has an eight-inch deep kickout sump, a crank scraper, windage tray, and trap door sump baffles. The one-way baffle doors are lightly spring- loaded to keep oil from leaving the sump area. (Image/Mike Mavrigian)

During test fitting, I checked for oil pump to pan sump floor clearance, Block pan rail to pump bottom measured 7.750 inches. Adding in a 0.100 inch crushed oil pan gasket, total pump to sump clearance was 0.350 inch.

The only glitch I ran into involved a clearance issue between the oil pump and a baffle in the lower rear wall area of the pan sump. The pump contacted the baffle, preventing the pan from moving rearward for proper bolt hole alignment. I trimmed the steel baffle to eliminate the contact. In fairness, Moroso designed the pan for a stock-style pump, which would have cleared just fine.

orange oil pan on an upside down v8 engine
The oil pan was secured to the block with an ARP oil pan stud kit. We decided to paint the pan Chevy orange to match the block. (Image/Mike Mavrigian)

The Dart block instructions call for a four-piece Fel-Pro oil pan gasket set. This gasket does not fit our Moroso oil pan as the rail mounting holes don’t align with the holes in the gaskets. We used a Moroso one-piece oil pan gasket which fit perfectly. The thick rubber/silicone gasket features a stainless core to prevent overtightening. I added a dab of Permatex Optimum RTV to all four corners prior to positioning the gasket and the pan.

I secured the pan to the block using ARP stainless steel studs. I installed the studs into the block rails hand-tight with Loctite 242 medium strength thread locker. The nuts were torqued to 12 ft.-lbs.

moroso oil filter installed in a v8 engine
Our oil filter of choice is this Moroso Race filter. It filters down to 27 microns and has a maximum burst pressure of 350 PSI. Other features include a bypass relief valve and an anti-drainback valve that keeps oil in the filter after engine shutdown. (Image/Mike Mavrigian)

Lifters

Our solid roller lifters are Morel Black Mambas. They have a 0.842 inch OD billet steel body and are 0.300 inch taller than the stock Gen. VI big block lifters. This is required to accommodate the taller lifter bores in the Dart block. Summit Racing carries Howards Cams RaceMax solid roller lifters that are a great alternative to the Morels.

Cylinder Heads

We chose Dart’s Pro 1 CNC aluminum heads for our 540. The CNC-machined heads have 121cc combustion chambers with 2.250 inch intake and 1.880 inch exhaust valves; 325cc intake and 129cc exhaust ports; and 1.625 inch diameter valve springs rated to 0.850 inch of valve lift. The intake ports are in the stock location and the exhaust ports are raised 0.300 inch from stock. Other features include manganese bronze valve guides, lightweight titanium retainers, and 10 degree valve locks.

Dart’s Pro 1 aluminum cylinder heads have CNC-machined 121cc combustion chambers, 325cc intake ports, and 129cc exhaust ports. The 1.625 inch diameter valve springs are rated to 0.850 inch of valve lift. The parts list has Pro 1 heads from Summit Racing. The specs are similar except for the 335cc intake ports, 138cc exhaust ports, and 2.300 inch intake valves instead of 2.250 inch valves. (Image/Summit Racing)

Summit Racing offers a similar Dart Pro 1 cylinder head. It is CNC-machined and has the same 121cc combustion chambers and 1.625 inch valve springs, but has larger 335cc intake ports, 138cc exhaust ports, and 2.300 inch intake valves instead of 2.250 inch valves.

I measured combustion chamber volume for each cylinder just to be sure. Each chamber checked out at 121cc as advertised—yet another testament to Dart’s attention to detail. Due to the open-chamber head design, our calculated compression ratio is 9.86:1. This streetable ratio will provide ample horsepower and torque on readily available 93 octane pump gas.

measuring combustion chamber volume with fluid
The Pro 1 heads’ open combustion chambers were verified at 121ccs with a CC measuring kit. The fluid is isopropyl alcohol mixed with blue dye for easier monitoring. (Image/Mike Mavrigian)

The heads were sealed to the block with Cometic MLS head gaskets and ARP head studs. The gaskets have an embossed design that promotes an even clamp load across the sealing surface to reduce bore distortion. The outer layers are coated with Viton fluoroelastomer rubber that is exceptionally heat-resistant.

The ARP head studs are designed specifically for the Pro 1 cylinder heads. This set features 12-point nuts that were torqued to 70 ft.-lbs. in three stages (30 ft.-lbs., 50 ft.-lbs., and 70 ft.-lbs.).

cylinder head studs installed on a v8 deck
The head studs are ARPs and the gaskets are Cometic MLS with a 0.040 inch compressed thickness. I test-fit all head studs prior to final assembly to verify that the shank shoulder above the lower threads does not contact the block deck. That would apply undue stress to the block. (Image/Mike Mavrigian)

Checking Piston to Valve Clearance

Piston to valve clearances were checked with a dial indicator and double checked with clay. With our COMP Cams solid roller cam set straight up and a cylinder head installed with no gasket, piston to valve clearance was approximately 0.100 inch at the intake valve and 0.030 inch at the exhaust valve. Adding the 0.040 inch thick Cometic gasket increased intake clearance to 0.140 inch and exhaust to 0.070 inch.

That’s too generous at the intake valve and too tight at the exhaust. By advancing the cam by four degrees, we tightened up intake clearance to 0.120 inch and opened up the exhaust to about 0.160 inch, a good compromise.

Determining Pushrod Length

Factory big block Chevy intake pushrod length is 8.275 inches and exhaust length is 9.250 inches. Dart notes that the intake pushrod should be around 0.200 inch longer and exhaust another 0.250 inch longer, but that you must measure to make sure due to variables like deck height, head gasket thickness, and cam specs.

ball tip of an engine pushrod
Our chromoly pushrods are 3/8 inch in diameter and have 0.137 inch thick walls for added rigidity. They also have 5/16 inch, 210 degree ball ends to accommodate extreme lift cams. We measured for proper length and came up with 8.450 inches for the intakes and 9.400 inches for exhausts. The parts list has COMP Cams Hi-Tech 210 pushrods that have very similar specifications except for slightly thinner 0.135 inch thick walls. (Image/Mike Mavrigian)

We started on the exhaust side with a pushrod length checker set at 9.450 inches. That made a witness mark pretty close to center on the valve tip, but just a tad toward the outside (exhaust side). Adjusting the checker to 9.400 inches provided a very satisfactory center witness mark sweep of about 0.050 inch wide on the exhaust valve tip.

The intake side proved to be stubborn. Setting the length checker to 8.450 inches netted a centered witness mark on the valve tip, but the sweep was wider than I liked at about 0.096 inch. I couldn’t improve on that, so 8.450 inch long pushrods it was.

The pushrods I chose were Elgin Pro Stocks. Made from 4130 chromoly steel, the one-piece pushrods are 3/8 inch in diameter with a 0.137 inch thick wall. They also have 5/16 inch, 120 degree ball ends to accommodate high lift cams. Summit Racing carries COMP Cams Hi-Tech 210 pushrods that have very similar specifications except for slightly thinner 0.035 inch thick walls.

Rocker Arms

The rocker arms are Harland Sharp’s Diamond Series full rollers. The forged aluminum rockers have a 1.7 ratio, clear 1.650 inch diameter valve springs, and eliminate as much as 100 grams from the valvetrain without sacrificing strength. The low-profile rockers fit under stock-height valve covers.

threaded studs
The Dart rocker arm studs have different lengths for intake and exhaust. The lower threads for the intakes are 0.800 inch in length and 1.300 inch for the exhaust studs. Be sure to coat the intake stud lower threads with thread sealer. All studs are final torqued to 55 ft.-lbs. (Image/Mike Mavrigian)

The Dart Pro 1 cylinder heads come with rocker arm studs with two different lower thread lengths. The 0.800 inch long studs are for the intake locations and the 1.300 inch long studs are for the exhaust. The exhaust rocker stud holes are blind, but the intake holes are open to intake port vacuum and require thread sealant on the studs’ lower threads. Pay attention and don’t mix them up!

rocker girdles on a v8 engine
Dart’s two-piece adjustable guide plates are connected by a socket head cap screw and locking nut. When test fitting, tapping the pivot point with a drift allows you to alter pivot angle and fine-tune to obtain proper rocker arm to valve tip centering. With rocker studs snug but not torqued, the guide plate pivot point is nudged using a drift and hammer to gently align the rocker roller bearing to the valve. (Image/Mike Mavrigian)

The Harland Sharp rockers use pushrod guide plates. The Dart Pro 1 heads include two-piece guide plates that are hinged at the center. When bolting the halves together the side with the Dart logo always goes on top of the other half without the logo. With the guide plates, rocker studs, pushrods, and rocker arms installed, closely examine the alignment of each rocker’s roller bearing tip to its respective valve tip.

man holding a performance rocker arm
The Harland Sharp Diamond Series forged aluminum roller rockers have a 1.7 ratio. They clear 1.650 inch diameter valve springs and eliminate as much as 100 grams from the valvetrain without sacrificing strength. The rockers are low profile, so they fit under stock height valve covers. The rockers were soaked in 30 weight oil for 30 minutes prior to installation. (Image/Mike Mavrigian)

Using a brass drift and a hammer to gently strike the fulcrum point of the guide plates, you can move and fine-tune the rocker arm rollers to properly center on the valve tips. Remove the rockers, torque the rocker studs to the final value of 55 ft.-lbs., and reinstall the rockers to verify alignment. If the rockers have moved, repeat the process.

offset rocker arms in a big block v8 chevy engine
Here is the left side cylinder head after adjusting the guide plates for proper rocker to valve tip alignment. Valve lash was set at 0.020 inch per the COMP Cam’s spec card. With our selected pushrod lengths, we had no clearance issues between guide plates and rocker arms at valve-closed positions. Once lash was adjusted, the polylocks were snugged to lock in the adjustment. (Image/Mike Mavrigian)

After soaking the rockers in 30-weight oil for 30 minutes per Harland Sharp’s recommendation, a dab of assembly lube was applied to the valve tips and the rockers installed with the supplied polylocks. Cold valve lash was set at 0.020 inch.

close up of valve spring and roller tip rocker arm
This is what properly centered rocker to valve tip alignment looks like after guide plate adjustment. (Image/Mike Mavrigian)

Stud Girdles

We installed a set of Dart aluminum stud girdles to tie the rocker arm studs together. This will reduce rocker stud deflection, which could have been a big issue with our stiff valve springs.

Installation is a bit tricky and definitely requires patience. First, lay the girdle assembly on the rockers with the Dart logo facing up. Loosely install the exhaust polylock nuts. Wiggle and slightly raise the girdle to get enough angle clearance to loosely install the intake polylock nuts. If you run across a polylock that won’t engage the rocker stud, wiggle/raise/lower the girdle to allow proper thread engagement. Don’t force it!

Once all polylocks are engaged, raise the girdle to a uniform height. It’s a matter of feel to obtain the desired “sweet spot” where the girdle is in its most comfortable location. Snug all polylocks until you achieve close to zero lash, then back off a few turns. Make sure that the girdle is not sitting low enough to interfere with rocker operation.

At this point, you can set valve lash, snug up the set screws, and final-tighten the girdle clamp bolts. Our COMP cam’s spec card calls for 0.020 inch hot lash. We set cold lash at 0.016 inch to compensate for component growth when the engine is at operating temperature.

Parts List

Keywords
540 Cubes of Fun, ARP, big block Chevy, COMP Cams, Dart, Harland Sharp, Howards Cams, Melling, Moroso
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Author: Mike Mavrigian

Mike Mavrigian has been building and writing about engines almost as long as there has been internal combustion. He has written well over 1,000 technical articles and seven books, and is editor of Precision Engine Magazine. Mike’s shop, Birchwood Automotive, specializes in street performance and racing engines and vehicle restoration. As you’ll see in this article series, he includes a wealth of information on his engine builds.