632 Big Block Engine

632 cid Big Block Chevy Nitrous Engine

Having retired as an automotive technician a few years back, John Messmore needed something fun to occupy his time. His love for building big block Chevys led him to opening his one-man engine shop, J Motorhead Racing Engines, in San Diego where he builds big cubic inch, big blocks like this 632 cid Chevy nitrous engine for grudge racing. Find out what goes into building this 2,000 horsepower beast!

Growing up with a dad who built race cars and drag boats for fun, John Messmore took a liking to cars and engine work at a young age. His first car when he was 16 was a ‘69 Camaro, and after tinkering with that, there was no looking back.

John went on to become an automotive technician, but always built engines on the side. He worked for Tipton Honda in El Cajon, CA until retiring a few years ago and opening J Motorhead Racing Engines in San Diego. J Motorhead Racing Engines is a one-man engine shop where Messmore specializes in big cubic inch, big block Chevy nitrous engines.

“After I built enough of my own cars and engines, people wanted me to start building stuff for them,” Messmore says. “That’s how it all got going. I just learned engine building from doing it for the past 20 years or so. I’ve been building engines at J Motorhead Racing Engines for almost 5 years.”

Messmore builds 12 to 15 engines a year and gets all of his machine work done at Total Performance. Because J Motorhead Racing Engines specializes in one-off, custom builds, some engines can take quite a while, like this recent build of a 632 cid big block Chevy nitrous engine for grudge racing.

“I just finished a 632, which was a really cool build,” he says. “This engine build came to me from my buddy Duncan who owns Barona Drag Strip. He came to me wanting to do a big nitrous motor to compete with other guys at the track. I had already built him a 569 cid nitrous motor that he set the track record with. He wanted something bigger because there’s other guys coming out with competitive stuff.

Dialing in the cam timing on the 632

“I’ve been wanting to do a 632 cid build with these Race Flow Development heads that are out on the market. They’re not that easy to get. Curtis Boggs is the guy who does them, and it takes months to get these heads, but they’re worth it. It’s worth the wait to have this guy make you a set of heads because he’s got custom CNC programs. Out of all the 14.5-degree style heads, his are the best flowing heads out there. This was always a build that I wanted to do if someone had the money to do it, and Duncan said let’s do it.”

In addition to the Race Flow Development 14.5-degree heads, the 632 uses an all-aluminum, Brodix ultra tall deck block with a 10.7˝ deck height. The block had a custom heat treatment and windowing done to it when it was ordered. It’s also got a .400˝ raised cam tunnel and a custom ground 60mm Bullet babbitt bearing camshaft in it, which Messmore admits doesn’t get done too often.

The 632 has a Brodix tall deck block, a Crower crankshaft, GRP rods, and Diamond pistons.

“The engine’s got an ultra-long 7.200˝ rod length – actually 7.196˝ – all-aluminum GRP custom rods,” he says. “We had Diamond make us a custom set of pistons for big power and big nitrous, which came with Total Seal piston rings. It’s got two Holley 1250 Ultra Black Dominators. The intake was made by HRE, which is a full custom, one-off intake.

“It’s got Inconel exhaust valves. The intake valves are 2.525˝ intake valve size. It’s also got a full T&D shaft-mount rocker system with Inconel exhaust rockers, which I haven’t seen a lot of. Manton made me a custom set of pushrods for it. The crank is a Crower Enduro crankshaft. It’s got a Jesel belt drive, PAC springs and retainers, Crower lifters, and Clevite H-series bearings.

“The engine has a Dailey Engineering 6-stage dry sump oiling system on it also and a lot of cool features that are going to work well with the combo. The engine also runs on nitrous and has two fogger kits from Induction Solutions.”

Just like any build of this caliber, there are inevitably road blocks and minor issues that come up during the build, which Messmore had to alleviate.

“There were clearance issues with the pushrods and the heads,” he says. “I had to dry assemble the engine a few times in order to get the clearances right as far as the pushrod to head clearance. I had to put a dummy spring on every single valve and then go through one at a time and just roll it through one at a time and mark areas in the head that I had to clearance for the pushrods. I used half-inch pushrods on the exhaust and 7/16ths pushrods on the intake with zero taper, so I had to get in there and massage the cylinder heads a bunch to get those to clear the way I wanted them to.

“I also had to massage the drain back oiling areas where I had scavenging for the dry sump in the back of the cylinder head. I opened that area up and made it to where the oil could flow through there quicker to get it out of the top end to get it back to the oil tank for the dry sump.”

This 632 big block Chevy has taken almost a year to build by due to all of the custom components.

“When everything is one-off, it takes time to get stuff done,” Messmore says. “The block itself had to go in the mill and get clearanced for the different rods that I went to. That stuff adds up.”

The customer, Duncan, is currently racing with Lizzy Musi’s old Pro Mod car, which has a J Motorhead Racing Engines-built 569 cid nitrous motor in it currently.

“With his old 569 cid motor, he ran 4.49 in the eighth mile,” Messmore says. “We’re going to pull that motor out and put the new 632 in. The new engine is capable of handling around an 800 horsepower shot of nitrous, and should make over 2,000 horsepower using both nitrous kits. The car should run in the low fours once it’s all dialed in.”

More than 2,000 hp lies sleeping inside.

Here’s to hoping it sets a new track record!

The Engine of the Week eNewsletter is sponsored by PennGrade Motor Oil and Elring – Das Original.

If you have an engine you would like to highlight in this series, please email Engine Builder magazine’s managing editor, Greg Jones at [email protected].

You May Also Like

427 cid Ford Windsor V8 Engine

This one-of-one Panozster we saw at the Cleveland Auto-Aviation Museum features a number of unique traits that make it a truly special roadster, including its 427 cubic inch Ford Windsor V8 engine! Check it out.

There’s an abundance of very cool cars out there in the world, but despite all those cool cars available, some folks would rather build a car that’s entirely their own, and therefore, a one-of-one example. That’s what we were treated to when we recently visited the Crawford Auto-Aviation Museum in Cleveland, OH – a one-of-a-kind, 1948 Panoz Roadster featuring a 427 cubic inch Ford Windsor V8 engine. We got the full rundown of this build, which took 13 years to complete, from the Crawford Museum’s Program and Marketing Manager, John Lutsch.

2,600 HP ProCharged 540 cid Big Block Chevy Engine

BB&T Racing in South Haven, MS has been building high-performance domestic engines for 30 years. One of their latest builds is for a drag racing customer looking to go faster utilizing an F3 ProCharger. Check out this 2,600 hp ProCharged 540 big block Chevy engine!

615 cid Big Block Chevy Nitrous Engine

It’s no secret that turbochargers dominate the power adders seen in drag-and-drive events, and to a lesser degree, superchargers. However, very few competitors resort to nitrous. Graham Hayes is one of those nitrous believers, and his Buck Racing Engines-built 615 cid big block Chevy engine put on a strong performance all five days of Sick Week 2023. Check it out.

468 cid Big Block Chevy Engine

Kevin Willms has owned this 1930 Ford Roadster since the age of 17. He’s now 62 and getting into the drag-and-drive scene with the roadster and its 468 cid big block Chevy engine. Check it out!

Sick Week’s Fastest 4-Cylinder – a Turbocharged 2.0L 4G63 Engine

Tony Niemczyk has owned his 1995 Mitsubishi Eclipse since 2001. Over the years, it’s been a constant evolution to get the car from a regular commuter to the point it is today – a streetable race machine with the claim of Sick Week’s Fastest 4-Cylinder and back-to-back Sick Week Freaks class wins. That’s thanks to a turbocharged 2.0L 4G63 engine. Check out the details!

Other Posts

Pat Musi Racing Engines’ Outlaw 4.840 Bore Space Nitrous Engine

We love every opportunity we get to speak with Pat Musi of Pat Musi Racing Engines. This time, we were down in Mooresville, NC to check out his shop in person and get the details of a few engine builds he had underway. This is an Outlaw 4.84 nitrous engine with 731 cubic inches of

Wilkins Racing Engines’ 632 cid Big Block Chevy Nitrous Engine

Sandy Wilkins of Wilkins Racing Engines recently allowed us to visit his engine and machine shop in Mooresville, NC. We were thoroughly impressed by how clean and organized his shop was and the caliber of the engines his shop churns out. We got the full details of this big block Chevy nitrous engine he built

Harrell Engine & Dyno’s 2,500+ HP Turbocharged 448 cid Billet LS Engine

We all know Pete Harrell of Harrell Engine & Dyno in Mooresville, NC is real good at doin’ stuff, like building high-horsepower, forced induction engines. Earlier this summer, we stopped by HED for a tour and to talk to Pete about some of the current builds he had going on. One of the engines nearing

Pro Motor Engines’ LS3 Engine Build for TA2 Racing

Pro Motor Engines in Mooresville, NC and owner Dennis Borem have a rich history in NASCAR and other forms of racing. We got to visit the shop earlier this summer, and the team was wrapping up a dyno session on a newly assembled LS3 engine for TA2 racing. We got the full details of the