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605 Drag Boat Engine

When his customer wanted to move up a class in drag boat racing, James Bostick of Bostick Racing Engines was happy to oblige. He built this 605 cid drag boat engine with nitrous for high horsepower.


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When James Bostick decided to open his own engine machine shop, he cashed out his retirement, bought some machines and founded Bostick Racing Engines in El Cajon, CA in 2008. Fast forward 12 years, and James now has a couple employees and a new 1,900 sq.-ft. facility.

With a focus on marine, Bostick does engine work for jet boats, river hot rods and drag boats, among others, but that doesn’t mean he won’t take on other applications. The shop will do automotive engines and even some restoration jobs too, and all the work on a Bostick engine is done entirely in-house.


Speaking of marine engines, however, Bostick recently finished up a 605 cubic inch drag boat engine for a repeat customer looking to move up a class. We’ll give you the details in this episode of Engine of the Week.

Hey everyone, I’m Crystal Smith with Engine Builder, and today we’re talking about a 605 cubic inch drag boat engine built by Bostick Racing Engines. This particular customer had Bostick built engines in the past, most recently a 468 cubic inch, single carb engine. As they moved up classes, Bostick added more nitrous, but that only got them so far. Here’s James to tell you more.


“These customers had always wanted to run the ADBA Lucas Racing QE class, which requires making 1,300-1,400 horsepower to do,” Bostick says. “They just finished a season and getting used to a new purpose-built drag boat using the old engine, which they’ve now run three or four years. While they were racing that engine for one last year, we started gathering up parts and came up with a plan for a big inch engine – nothing real strung out, something user friendly, low on maintenance and easy on parts. We went with a larger inch engine and then started putting it together.”


The 605 drag boat engine was built around Edelbrock 14-degree cylinder heads, which made getting all the other parts a bit more of a process.

“We started off with Edelbrock 14-degree heads that we hand blend ported,” he says. “We ended up having to have a lot of parts made because it was one of the first times that a few of these companies had dealt with these heads. We picked those heads because they were very nitrous friendly and something that was not going to be real finicky on the tuning.”

The block for the 605 came from World Products, which Bostick Racing Engines machined in order to get the proper clearances they wanted. From there, the shop finished the valve job and sent the heads to CP so they could make models to spec the right pistons for the engine.


In addition to CP pistons, the drag boat engine got equipped with Manley valves, a new crank and rods, Jesel shaft rockers, a Schneider cam, Clevite coated bearings, Crower lifters, Manton pushrods, a pair of Holley 1050 Dominators, a Profiler tunnel ram intake, an Edelbrock fogger, and a Dailey Engineering dry sump oiling system.

“We basically just had to figure out how to make everything work as far as the cylinder heads go,” he says. “A couple places we ran into problems was trying to get the pistons to work with the heads as far as trying to get enough dome volume without the pistons hitting valves.


“The other issue we ran into was trying to get everything – the rods and crank – to fit in the crank case without hitting places. Other than that it was pretty straightforward. Nothing was overly complicated, but those were little things that made it to where it wasn’t a matter of ordering up parts out of your Summit catalog and then just throwing a pile of parts together.”

Once Bostick had the engine assembled and ready to run, he took it to Westech for dyno work. That evaluation proved this 605 cubic inch engine, with a 14 to 1 compression ratio, could churn out more than 1,100 horsepower at 7,300 rpm and 900 pound-feet of torque. With a small nitrous tune, the engine made 1,400 horsepower and more than 1,100 pound-feet of torque.


“We didn’t want it to have to turn 8,000 rpm, so we targeted a lower 7,000 rpm range so it’d be a lot easier on parts,” Bostick says. “The nitrous tune up was basically the smallest we could put in the fogger, so it really likes the nitrous. That’s the way we cammed it and geared it towards. This engine will run good on motor, but we really wanted it to shine on nitrous.”

The engine liked the nitrous indeed! On just a 250 shot of nitrous the engine picked up 300 horsepower. With a larger tune this engine could get up to about 1,600 horsepower, according to Bostick. All that’s left to do now is have some fun on the water! Well, that does it for this episode of Engine of the Week. Please like, comment and subscribe to our page if you haven’t already. And if you have an engine you’d like to see featured, please email our editor Greg Jones at [email protected] Thanks for watching!

Engine Builder Magazine