Chris Lewis (left) elected to run a Chevrolet Performance 604 engine in his limited late model for one chief reason. It fits his budget. For about $900, Lewis and friend Casey Neeley (right) rebuilt their 604 themselves.
Lewis raced 604 late models prior to moving into limiteds last season. His old 604’s block cracked, so he built a new spec engine to run the Topless Outlaws. Mid-season, however, catastrophe hit. Lewis dropped a valve and blew up the new spec engine. His old 604 engine still sat in his shop.
“We found a [604 engine] block for $250,” Lewis, 26, of Lenoir City, Tennessee, said. “When most of the big crate late model racers get an engine freshened, they’ll often get a new block. We honed up the cylinders and made sure we were in the allowance for the spec of the engines.”
However, the engine needed more work than just a new block.
“We got this harebrained idea,” said Lewis. “Let’s see if we can get a rebuild kit from an auto parts store.”
Lewis and Neeley were in luck.
“I’m sponsored by Cobb’s Auto Parts in Loudon, Tennessee, but any auto parts store, as long as it’s a Chevrolet pickup truck ZZ4 motor, you can buy the rebuild kit and everything goes right in,” Lewis said. “The rings fit, the bearings fit, and the head gaskets fit. The only thing that is different are the intake [manifold] gaskets. They won’t work, because it’s a Vortec-style intake [on the ZZ4 engine]. The 604s have a single-plane intake, which is more of a traditional [Chevrolet] small-block style.”
Topless Outlaws’ owner Mike Robinette welcomed their creation.
“As long it’s GM-spec, we’re good,” said Lewis. “As long as it P&Gs the same cubic inches [as a 604 engine] and passes the Cam Doctor [to check the lift and lobe separation], we’re legal.”
While using a 604 engine kept Lewis in the game, he competes at a serious disadvantage.
“I would say this  motor is at 450 hp,” Lewis said. “My spec motor, which was nothing extravagant, with no ported heads, it made 680 hp.”
Chris Lewis cannot enter his car with his self-rebuilt engine in most 604 classes as it lacks the required seals.
“There are some engine builders who will seal it,” said Lewis. “They’ll have to verify that it’s within spec. [The costs anywhere from] $500 to $800. Some engine builders won’t do it, because it’s their name on the line and you didn’t buy anything from them. I understand that.”
Instead of the limited late models, Chris Lewis could run the sportsman class against cars running engines of the same caliber as his. He would only have to change his shocks.
“I get stuff tore up [in the sportsman class],” Lewis said. “In the limiteds, most of the time the guys race you cleaner.”
Fortunately, Lewis and Neeley are working on a spec engine solution.
“Our old spec motor’s block is cracked,” said Lewis. “We’re converting our crankshaft in the spec engine to a single one-piece seal to run a crate block. We’re getting a [crate engine] block, which came into an engine builder illegal [for crate-specific classes] or has come to the end of its life. It’s already a racing block and it’s a cheaper alternative to [other engine blocks]. All we got to do is bore it to what I’m going to build, a 360-cid [engine]. We’re going to be reboring the block and deck it a little more than a crate. I got a good Callies rotating assembly, Comp Cams camshaft, and a set of Brodix heads, and now it’s a spec motor.”
The Outside Groove Executive Editor has covered motorsports since 2000. His many awards include the 2019 Eastern Motorsport Press Association (EMPA) Jim Hunter Writer of the Year and the 2013 Russ Catlin Award for Excellence in Motorsports Journalism.