Jason Line 557 Big Block, bare block
Jason Line Big Block, crankshaft installation
Jason Line Big Block, two-piece rear main seal
Jason Line Big Block, Diamond Pistons
Jason Line Big Block, Total Seal piston rings
Jason Line 557 Big Block, connecting rods
Jason Line 557 Big Block, camshaft installation
Jason Line 557 Big Block, Jesel belt drive system
Jason Line 557 Big Block, Stef's Oil Pan installation
Jason Line 557 Big Block, setting compression ratio
Jason Line 557 Big Block, Trick Flow PowerPort 360 heads
Jason Line 557 Big Block, head port work
Jason Line 557 Big Block, valvetrain
Jason Line 557 Big Block, Trick Flow R-Series intake
Jason Line 557 Big Block, Willys Carburetor installation
Jason Line 557, assembled engine
Jason Line 557 Big Block, dyno numbers

Jason’s Biscayne wagon weighs approximately 4,500 pounds—about twice as much as the Pro Stocker he drives in the NHRA Full Throttle Drag Racing Series—so he needed some big cubes. Here’s the GMPP Gen VI 502 block he used as the foundation for the Biscayne’s engine. It was bored to 4.500 inches, align-honed, and jet-washed before the build.

The main bearings were pre-fitted with clearances between .0025-.0030 inches—the typical range the team shoots for with its Pro Stock engines. Jason chose an Eagle Specialties forged crankshaft to handle the 812 horsepower and 7,000-plus rpm.

Gen VI blocks are designed to work with one-piece rear main seals, but the Eagle Specialties crankshaft required a two-piece rear main seal. To make the block and crank work together, Jason used a special B&B adapter to give the rear main seal a place to sit. End clearance was set at .005 inches before the main caps were torqued to 105 psi.

Jason chose Diamond pistons, which are used on the team’s Pro Stock engines. The team has its competition pistons vertically gas ported, but for this street-oriented 557, Jason went with lateral gas porting. The gas porting allows cylinder pressure to get behind the top ring and push the ring against the cylinder wall for better sealing.

Jason used a set of Total Seal piston rings. An oil ring spacer was installed because the compression height of the piston caused the wrist pin bore to break into the ring lands. Jason used a fish scale to set the oil ring tension to 11 pounds of drag to keep the engine from oiling or smoking.

The pistons were installed on a set of Eagle Specialties 6.385-inch stroke, H-beam connecting rods. Diamond recommends a .0065-inch piston-to-wall clearance, but Jason elected to go with a tighter .0060-inch clearance to keep the engine running quieter.

The 254-degree intake/270-degree exhaust duration (@.050-inch lift) COMP Cams camshaft was installed and secured with a Jesel front cover. A custom ground, solid roller cam and lifters were used to avoid the high rpm “valve float” sometimes associated with hydraulic valvetrain setups. Cam endplay was set to .005 inches using a set of shims, which come with the cam seal.

Jason opted for a Jesel belt drive system. With numerous dyno runs in store for the 557, he wanted something that was user-friendly and easy to adjust.

The oiling system features a Stef’s standard-volume oil pump and Stef’s aluminum oil pan. The lightweight pan uses a baffle and trap door setup to keep the 557’s oil under control.

Using a bridge dial indicator, Jason found that the pistons protruded from the bore by .005 inches, effectively lowering the deck clearance and increasing compression. Since he was shooting for .046 inches of deck clearance, Jason opted for a set of .051-inch thick Cometic MLS gaskets to increase the deck clearance the proper amount. The result is a 9.8:1 compression ratio.

Jason turned to Trick Flow Specialties for a set of PowerPort 360 cylinder heads. Although the heads flow well right out of the box, Jason couldn’t resist putting his own stamp on the castings. In their off-the-shelf form, the heads have 360cc intake runners and deliver an impressive 365 cfm of airflow.

Using his years of experience with top-end engine components, Jason did his own port work on the heads. He welded material on the intake runner floors, effectively raising the runners by .150 inches. He left the cross sectional areas alone but changed the intake valve angle from 45 degrees to 50 degrees. Once he was finished, the intake runners were still 360cc, but airflow was increased from 365 cfm to over 400 cfm. You can look for Trick Flow to carry Jason’s version of the PowerPort 360 heads in the near future.

For increased valvetrain stability, the rocker arms were welded together—a trick the team uses on its Pro Stock engines.

Trick Flow’s R-Series intake features a single plane design for 500-plus cubic inch engines—perfect for the 557. Jason sent the manifold to Wilson Manifolds, where it was massaged and port-matched to the custom runners he created for the Trick Flow heads.

The Trick Flow intake works with Holley Dominator-style carburetors. Jason’s carb was outfitted with a set of Willys Carburetor and Dyno Shop metering blocks and bolted onto a Wilson Manifolds spacer to enhance airflow and air velocity.

The 557 big block looks impressive—but could it deliver the impressive power numbers Jason was looking for?

The answer: a resounding yes—and then some! Thanks to this Pro Stock-inspired 557, Jason’s 4,500 pound Biscayne wagon has no trouble getting the Line family to the grocery store fast!

It started off innocently enough. Following a race in 2010, Summit Racing Equipment NHRA Pro Stock driver Jason Line bought a 1968 Biscayne station wagon as a side project and laid out a quick, simple plan: take an old 427 motor from a donor car, refresh it, and drop it harmlessly between the frame rails of the wagon.

Then came Plan B.

“Almost from the start, the guys at the shop were hacking on me about putting a relatively stock engine into the wagon,”  said Jason, who also builds and tunes the engines for the Summit Racing-sponsored KB Racing Pro Stock team. “That started me thinking. One thing led to another, and before I knew it, I was starting to assemble the pieces for a completely new custom motor.”

Jason’s “Plan B” was to build an all-new 557 cubic inch mill with the goal of topping 750 horsepower on pump gas. “A lot of people build 540s, 565s, or 572s, but I wanted something a little different,” Line said. “Basically, I wanted a race engine with low compression so I could drive it on the street.”

Jason started with a GM Performance Parts Gen VI 502 block with four-bolt mains to handle the considerable power he had planned. He had it bored out to 4.500 inches and clearanced for a 4.375-inch stroke crankshaft, producing 557 cubic inches. He then contacted Summit Racing to help piece together the components for the build.

The rotating assembly includes an Eagle Specialties forged crank, Eagle Specialties H-beam connecting rods, and Diamond coated pistons. The top-end is anchored by a set of Trick Flow PowerPort® 360 cylinder heads, which got some special attention from Jason. Using his NASCAR and NHRA engine building experience, he altered the intake runners to increase airflow from 365 cfm to over 400 cfm. A port-matched Trick Flow single plane intake and a Willy’s carburetor complete the top end.

The valvetrain centers around a COMP Cams solid roller camshaft, which Jason says is mild and durable enough for the street without sacrificing the power numbers he was shooting for. In fact, the 557 exceeded Jason’s goals, delivering 812 horsepower on the dyno.

“Anyone can duplicate this build using parts right out of the Summit Racing catalog, bolt it all together without the extra port work, and get close to the horsepower we made,” Jason said. “That would certainly be enough for most people, but our team motto is: anything that can be done can be overdone.”

Jason Line’s 557 is proof of that.

Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.