Crate motors cut costs, but they almost always deliver less power than a purpose-built engine. On the face of it, a purpose-built custom motor should always have the edge, but there's one area where a crate motor has the potential to play catch-up as far as power is concerned. Imagine you're an experienced engine builder, and you have to build a custom but basic street motor for a single customer. You have to get it right the first time around. But what if you knew you were going to sell hundreds? Then you could afford to do some serious development. If crate motors are built in sufficient numbers, there is the opportunity to refine a spec optimally for a given price, because high R&D costs are spread out over many engines.
Blueprint Engines (a division of Marshall Engines) is in this position. As one of the largest independent engine builders in the country, Marshall builds a complete line of replacement engines. Under the Blueprint label, Marshall sells performance engines through speed shops, performance outlets like Jegs and Summit, and automotive mass merchandisers like AutoZone. These engines also come with a 30-month, 50,000-mile warranty for street applications.
With a big-time warranty, reliability is a prime issue. Unless you've been living on another planet, you'll have heard that the removal of zinc additives has been causing cam companies and their customers flat-tappet woes. Zinc (in the form of ZDDP) is a high-pressure lube that is a necessity if a typical flat-tappet cam is to survive. Without ZDDP, a cam's chance of survival is way less than 50 percent. If you were selling 1,000 engines a month, how long would you be in business if 500 came back under warranty?
Blueprint starts with a hand-selected,...
Blueprint starts with a hand-selected, seasoned block that is bored, honed, align-honed on the mains, and decked. After that, a coat of engine enamel is applied.
Blueprint was quick to appreciate that they had to have a solution in place before the time limit for ZDDP use ran out. Using their considerable in-house technology, plus that of COMP Cams, Blueprint committed themselves to a long and tedious development program that allowed them to offer engines equipped with the meanest flat-tappet street cam profiles available. So since they were tying up dyno time for hundreds of hours, it seemed that it would be a good idea to also test everything else in an effort to refine the engine spec for max horsepower.
Reliability & Power
So was adopting this strategy a good move? It seems so, as Norris Marshall, president of Marshall Engines, showed me dyno sheets that indicate a 55 ft-lb and 65 hp increase on what is essentially their base flat-tappet small-block Chevy performance crate motor. This is what can happen when the dyno time is extensive, allowing tests of a multitude of intakes, cams, and heads. All the dyno testing for power and reliability allows Blueprint to target more hp per dollar combined with an extended life.
At this point, I got to talking with Tony Brown, longtime racer, and now race series promoter. Tony was of a mind that bracket racing still fell short of the needs of budget-constrained racers who wanted true head's-up racing. Operating out of Atlantic Racing (his Charlotte, North Carolina, speed shop), Tony started the PTRA (Pro Tree Racer's Association) in an effort to address that situation. Tony has brought a considerable amount of experience building and racing cars in other series in structuring the rules for the PTRA.
Here is the Scat/KB rotating...
Here is the Scat/KB rotating assembly that Blueprint uses in their 383s. By selecting either dished or flat-top, a compression ratio between 9:1 and 10.25:1 can be had. Our engine used forged flat-tops for the higher 10.25 ratio. The bushed-pin Scat stroker rods feature 7/16-inch ARP bolts, and are good to 800 hp.
To make the series work, there had to be a class to fit every budget. At the entry level, Tony devised the Performance Street class, which is designed for American-made cars with the word "budget" strongly infused. (For the rules, go to www.headsupsuperseries.com) Essentially, the rules are structured so that if you have a small-block Chevy making about 480-500 hp in a well-set-up chassis at the mandated minimum 3,100 pounds, you have a real chance of making it to the quarter-finals if you cut a good light.
I took a look at the class rules, and figured it would be a great one in which to run a Blueprint engine. Here was an opportunity to see if claimed dyno numbers actually measured up to real-world performance. That's when Tony told me his dad (who started racing in the mid-'60s) had a nice '79 Camaro with no motor. A look at the car convinced me to call Blueprint Engines' Norris Marshall to ask if he was willing to showcase the capability of his engines. It was, in essence, put your money where your mouth is. I explained that to stand any chance of being competitive, we needed 480-500 hp. Would the base Blueprint flat-tappet motor be up to the job? Then Norris made a point that is worth our consideration. Blueprint Engines uses a relatively conservative DTS dyno. As we know from the Engine Masters Challenge, the DTS dyno tends to read lower than a SuperFlow. Off the top of his head, he told us the engine we were looking at made about 465 hp, and he would be happy to see it square off against engines that claimed 490 hp. The implication is that the BS stops when the green flag drops.
We chose Blueprint's baseline, flat-tappet 383 street motor. To make it eligible for PTRA Performance Street, it actually had to be detuned some. Normally, this engine comes with an air-gap intake and an 800-cfm carb; examples of such on Blueprint's DTS show right around 460 hp and 492 lb-ft. As things stood, it looked as if a 460hp Blueprint crate motor could fare reasonably well against 490 hp from other sources, but there was the rule-mandated intake manifold and carb to deal with. The starting power figures had the advantage of a more performance-orientated intake manifold and carb than allowed by the rules. To qualify for PTRA Performance Street, we needed a non-air-gap manifold, a 750 Holley (Part No. 4779), and exhaust collectors of no more than 21/2 inches in diameter, plus a muffler. We could be giving away as much as 15 hp here. Although it would still be a ton of fun, I began to doubt if we could do better than midfield if we were no more than 450 hp, but the white Camaro looked so lost without an engine that I decided to go ahead anyway.
The crank for our 383 build...
The crank for our 383 build was from Scat. Shown here is the Scat forged crank upgrade option, which is about $440 more. We elected to use the lower-cost cast crank, as this is good to well over 600 hp.
To make sure the engine was at its best, Blueprint agreed to test all the non-air-gap intakes that were eligible; Norris also had his carb supplier build a blueprinted 750 Holley.
The Blueprint 383 short-block is centered around a selected, seasoned block, which goes through all the basic machining procedures that a race block would see. That includes a rust/carbon strip process to get the block down to virgin cast iron. From there, the block is given a pre-machining inspection. If it's OK, it gets bored, honed, align-honed on the mains, and decked to 9 inches flat. After a coat of engine enamel is applied, it's ready to go.
For a rotating assembly, Norris points out that it is important to go with a company that makes stout stuff, because anyone who's good at building power is better than average at breaking parts. With that in mind, Blueprint wanted (even for their base engines) tough, cost-effective parts. Blueprint chose Scat cranks and rods, and based on what they've seen over many years, they saw no point in changing that. If a new crank is in the cards, it may as well be a 383 stroker crank with a set of heavy-duty stroker-clearanced rods. With that many cubes to fill, it's important to get the cylinder heads and valvetrain right on. For pistons, Blueprint offers several depending on the application, but for the most part, it's KB slugs equipped with a Sealed Power moly ring set.