Finding An Oil Pan To Fit A Big-Inch Stroker Big-Block

Many street/strip and hardcore racers are picky about the parts they use. Take for instance the oil pan. It’s hard to argue the engineered benefits that are provided within an aftermarket oil pan. Just some features included in these pans range from proper acceleration and deceleration baffling, a crankshaft scraper and uni-directional windage tray, along with clearance for big crankshaft stroke combined with larger aluminum or steel rods. But, many times, space is an issue when fitting these larger pans in the car. You will be happy to know, the previous list of benefits is achievable without the need to hack away at the crossmember beneath your engine?

Our “Project Rover” got its name because we wanted to teach an old dog new tricks. That was evident with our stout 489-inch big-block Chevy. The stroker crank is connected to large H-beam connecting rods that nearly kiss the rail area with our previous stock Corvette-style oil pan.

Finding One That Fits

In regard to wet-sump oil pan selections, many of these benefits are exclusive to much larger and deeper oil pans. If you are sporting a traditional front subframe, you can easily fall under the “some frame modification is necessary” disclaimer. As a great alternative, Moroso Performance has designed multiple oil pans that offer a high degree of oil-controlling assets and still provide the ability to avoid modification of your front frame’s crossmember and steering setup.

For our 1968 Camaro, we noticed Moroso offers a wet-sump oil pan (part number 20416), which is a standard 8-inches deep. This steel pan also offers a larger six-quart capacity via two “kickouts” on each side of the sump area. What’s more, these kickouts do not interfere with the factory located oil filter or even the biggest tube headers we use.

One of the more notable features of our new Moroso six-quart pan is the thicker pan rails with integral stroker notches built-in. These notches accept up to a 4.25-inch stroke when combined with steel rods.

When it came time to select a pan for the Camaro, Thor Schroeder, marketing manager at Moroso Performance, chimed in on our specific pan application. “This is a good fit for your 750-horsepower bracket racing Camaro,” he says. “Until you enter the 1,000-horsepower range or dip into the low 9-second zone, this is an optimal pan to bolt in and go.”

This oil pan’s construction begins with a quality core made from a heavier than OEM-gauge steel stamping. “Some of our cores are stamped here in the U.S., and some come from overseas,” he continues. “This specific pan stamping is custom-designed by Moroso to provide stroker clearance at the pan rail.” 

Since each pan part number offered by Moroso utilizes a dedicated fixture, I asked just how many total fixtures are located within the manufacturing facility. Schroeder responded, “Holy cow, I will have to do some serious research for that answer. I have been in this industry almost 25-years, and we have new fixturing for new designs in a constant state of development.”

Until you enter the 1,000-horsepower range or dip into the low 9-second zone, this is an optimal pan to bolt in and go. – Thor Schroeder

Correct Pumping

The Moroso catalog is filled with more high-efficiency oil pump pickups to match each oil pan and performance/racing oil pump combination. Schroeder explains, “Depending on the size and volume of the pump you are using, we have a chart on our website called the Chevrolet Oil Pump Pickup Buyers Guide that can help choose precisely which pump pickup is suited to your combination.”

The raw pan rail stamping is inserted onto a Moroso-designed fixture system where the in-house fabrication team fabricates each individual pan’s kick-outs, baffles, and crank-scraper windage tray features. Once completed, each pan undergoes a pressurized leak test.

With the help of the Moroso buyer’s guide, we outfitted our new oil pump with a pickup tube that is matched to the new pan’s depth. These Moroso pickups not only mate to the respective pan’s depth, but they also feature rectangular high-flow pickup and a tube brace that connects to one of the oil pump’s cover bolts.

If you compare the pickup-tube screen to a factory Chevrolet unit, it is evident that the screen is much more conducive to drawing oil through the pickup at a much higher capacity.

Not only does our Moroso pan clear the crossmember in most popular General Motors cars, but it will also not interfere with the original steering links located behind the crossmember. The six-quart capacity "kickouts" at the pan sump area will also clear all OEM starters and oil filters.

We have elaborated about the pan’s fitment but there is more to this pan. The most significant internal features offer what you need for high RPM: windage prevention and oil control under hard acceleration and deceleration.

Benefits Galore

The most obvious performance benefits are the crankshaft scraper and windage screen. Both of these features are designed to pull excess oil windage. Windage is the flow of air/oil within the crankcase. When a piston starts its downward stroke, air under it is pushed into the crankshaft area. During a piston/crankshaft compression stroke, the air is being sucked up behind it. The windage tray greatly helps keep oil in the sump area and not pulled into the rotating assembly.

oil pan

A crank scraper and uni-directional windage tray can add horsepower and greatly alleviate air/oil windage. These features, along with the trap door baffle system, keep uncavitated, or oil not aerated, available at the oil pump.

One baffle, commonly called the “trap door,” opens and closes to allow a one-way fluid flow towards the sump area during hard acceleration. Although this is a serious performance need, Moroso also incorporates this baffle into many of its oil pans.

“The hinged door is allowed to open about one-third of the way,” explains Schroeder. “This precisely allows a feed of oil to the pickup area, but not too much. It is also designed to close quickly under deceleration to restrict the oil from moving forward and starving the oil pump.”

We mated a Moroso oil pump pickup tube specified for this pan. To ensure our new oil pan and pump combination combine for proper clearance, we simply use a straight edge and ruler to ensure our pump is 7.75-inches deep, which provides a ¼-inch clearance with the pan bottom.

Fluid Containment

Finally, a Moroso one-piece oil pan gasket was an obvious choice for our pan installation. It is also notched like our new pan for additional rod and stroke clearance. The installation is very straightforward because of the sturdiness of the gasket. It has a steel reinforcing shim cast within. I use a permanent yellow trim adhesive to affix the gasket to the pan as a personal choice. When the pan requires removal, the gasket will easily come off the block still glued to the pan.

When an OEM pan is used for racing, many racers will replace the dipstick tube with a tight-fitting fastener (bolt) slathered with a liberal amount of RTV sealer. This is an old-school trick done in high-performance or racing engines with a combination of extreme compression, long-stroke, and frequent high-RPM events. If not using a crankcase evacuation system, the aforementioned air pressure that builds up under the piston can cause crankcase pressure to build and easily push the factory-style dipstick out of the tube, causing an oil-saturated engine bay, hence, the plugged dipstick hole.

This new Moroso pan features a 3/8-inch NPT bung welded to the pan at the dipstick location. With the Moroso pan, you can use an actual pipe plug to seal the dipstick provision. However, this will negate ever checking the oil.

It is easy with a Morso pan to leave the oil dipstick provision capped with an included NPT plug, but there is a viable choice. Moroso also offers something we jumped on; it is a new twist-lock dipstick designed to seal at the pan at the NPT fitting tightly.

We opted to use Moroso’s twist-lock dipstick (part number 25973) It tightly seals at the oil pan fitting and having a way to periodically check the oil is a necessity. This will keep our engine sealed, and allow us to monitor the oil for fuel contamination since we will be running E85 and/or methanol.

The Moroso dipstick uses a heavy-wall tube that is easily formed with a tubing bender to careen around your specific headers. The dipstick features a positive locking adapter at the pan that stops oil leakage caused by increased crankcase pressure.

I am enthused with the concept of applying many of the Moroso oil control properties to our Camaro without the task of butchering huge notches in the crossmember. A pan with features that Moroso also uses within a Top Fuel part number has me pretty stoked that our 489-inch big-block now has far improved oil control in the crankcase.

Article Sources

About the author

Todd Silvey

Todd has been a hardcore drag racing journalist since 1987. He is constantly on both sides of the guardwall from racing photography and editorship to drag racing cars of every shape and class.
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