At $1,900, a Larry's Performance...
At $1,900, a Larry's Performance 454 short-block is a bargain. This one was filled with Speed-Pro hypereutectic pistons; forged slugs cost only $100 more. Want to assemble it yourself? Bring Larry's a core and you'll get it back, ready to fill, for $425.
The Merlin III cast-iron block...
The Merlin III cast-iron block features a thick deck, stronger main webs and bulkheads, and a priority main oiling system. It's available with 4.240-, 4.490- or 4.590-inch bores, ready for finish-honing or race ready, and in standard or tall-deck versions. Prices for the former start at $1,860 through Summit.
Shafiroff's 745hp 582 engine...
Shafiroff's 745hp 582 engine uses 6.535-inch rods in a Merlin standard-deck block. It's topped with Dart Pro 1 345cc heads and runs a streetable 10.5:1 compression ratio, all for $10,500.
Merlin big-block heads come...
Merlin big-block heads come in four different configurations to support a variety of applications, including both oval- and rectangular-port iron heads. This one's a Merlin III aluminum head with 350cc runners.
The 540 Hardcore big-block...
The 540 Hardcore big-block from World Products makes 630 hp with aluminum heads. It's already one of World's best-sellers, and a recently developed hydraulic-cam setup adds 30 hp.
Donovan's aluminum big-blocks...
Donovan's aluminum big-blocks can accommodate 850 ci, if not more. They're lightweight (140 pounds), and their reparability lends them to race duties. Expect an engine builder to add at least $3,500 to the tab if you just have to have one.
Q&A With Jack Mcinnis of DartT Machinery
CHP: What's the going rate for a Big M block these days?
Jack McInnis: It's around $2,200-$2,300 for a standard-deck-height Sportsman, and $2,600-$2,700 for the Comp version. The main difference is that the Sportsman has ductile iron main caps.
CHP: How do those prices stack up against the competition?
JM: We try to have a fair price, but we don't merely try to meet the bottom line. We prefer to have a quality product.
CHP: That being said, are the Big M blocks selling well?
JM: Yeah, they are, absolutely. We're doing a good business in those blocks.
CHP: What's your take on that?
JM: By the time someone finds a core, has it inspected, and has the machine work done, they're close to the price of one of our blocks. When you buy one of ours, it's virtually ready to go.
CHP: What are the other reasons to go with a Big M block?
JM: Once somebody makes the move to a good aftermarket block, they won't go back. The thicker cylinder walls have many more rebuilds in them--or room for more displacement. With a good 454, you can go 0.060 or 0.080 over. You can go almost 0.400 over with ours, or just get it with a 4.600-inch bore.
CHP: What are the other advantages of the Dart block?
JM: For one, the block webs are much thicker and stronger. The scalloped water jackets improve cooling, and the "true" priority main oiling system makes sure the main bearings always have enough lubrication. These blocks are also made from a much harder, denser alloy than a stock block. Someone would have to spend a lot on a stock block to get even close. The value someone gets with a Dart block is tremendous.
CHP: Dart is also in the cylinder head business. What's you best-seller in that department?
JM: That would be our Pro 1 aluminum heads. They go for $1,200-$1,400 apiece. Most of the standard GM stuff came as rectangular, so we accommodate that. We created our new 275cc oval-port head to fill that niche. It'll be good for 454- or 468ci hot street motors. The port size increases air velocity, and therefore performance.
CHP: What's the most common mistake you see when it comes to choosing big-block heads?
JM: Everyone thinks bigger is better, but it depends on what you use the thing for. If it's a street car that goes to the strip every once in a while, it'll be happier with a smaller head.
| Common bore x stroke combinations |
| BORE | | STROKE | | CI |
| 4.250 | x | 4.000 | = | 454 |
| 4.310 | x | 4.250 | = | 496 |
| 4.470 | x | 4.000 | = | 502 |
| 4.500 | x | 4.250 | = | 540 |
| 4.600 | x | 4.250 | = | 565 |
| 4.560 | x | 4.375 | = | 572 |
| 4.600 | x | 4.375 | = | 582 |
| 4.600 | x | 4.500 | = | 598 |
Q&A With Jim Escamilla Of Larry's Performance
CHP: What's your most popular big-block?
Jim Escamilla: Our best-seller is our 454 four-bolt main short-block. It goes for $1,995 with forged flat-top pistons. It would come in at 9:1 or 9.5:1 compression with small-chamber heads.
CHP: Do you mostly sell short-blocks?
JE: Ninety-five percent of our big-block sales are short-blocks. Some guys might buy a set of aluminum heads, but I find that most hot rodders already have a set they want to use.
CHP: What type of cam do you put in most of them?
JE: Ninety percent go out with hydraulic flat-tappet cams. Most guys we sell to just want a solid motor.
CHP: How about crate motors?
JE: We do have our 496 Track Pro package. It comes with a Scat cast crank, SRP forged pistons, and GM Track Pro oval-port heads. We rate it at 496 hp and 550 lb-ft of torque, and it sells for $5,550.
CHP: Do you get much call for anything more radical?
JE: Yes. We're currently working on a 14:1 forged dome-piston motor. The customer wants it for a local annual race event called the Hangover Nationals. We can do stuff like that, but how many people can afford to buy it?
Q&A With Ben Smeding Of Smeding Performance
CHP: So what's Smeding's most popular big-block?
Ben Smeding: I'd say it's our 540 Extreme. It makes 620 hp and comes turnkey and fully dyno'd for $10,995. It's sort of a high-end motor.
CHP: What's it based on?
BS: We use a Gen VI 502 block with a 4.500-inch bore and 4.250-inch stroke. It comes with a hydraulic-roller cam. Maybe one out of 10 ask for a solid roller. We used to do a 454, but it pretty much cost the same as the 540.
CHP: What other big-blocks does Smeding build?
BS: The 565 Extreme and the Blown 540 are our other regular builds. The 565 uses a standard-deck Dart block and CNC-ported heads. It makes 690 hp and goes for $12,995.
CHP: How would you characterize these two engines?
BS: The 540 is more of a cruiser engine, while the 565 is more for street-strip duty. It seems to be for the younger guy who wants to flex his muscles more.
Q&A With Scott Shafiroff Of Shafiroff Racing Engines
CHP: You build a lot of different big-blocks. Which one packs the most bang for the buck?Scott Shafiroff: That would be our UltraStreet 540/695hp Classic. It goes for $8,995. And it can be upgraded to more than 700 hp by switching to the Dart Pro 1 CNC heads. So for less than $9,500 you can get 725 hp.
CHP: What trends are you seeing in the big-blocks people are buying?
SS: Hydraulic-roller cams are very popular, though I say the good ol' solid roller is still best.
CHP: What else have you noticed among those who build big-blocks?
SS: The biggest problem with horsepower per dollar is that people immediately think about a bigger cam and heads, but no one wants to spend money on the short-block. Everything has to be in balance. That's what a good engine shop does for a guy.
CHP: Are there options besides buying a complete engine?
SS: We sell a 540 short-block with the cam degreed in. People don't have 10 grand, but they may have five and a set of heads they want to fit on. A lot of people like to put it together themselves. We also sell a lot of short-blocks along with heads for the same reason.
CHP: Are there any advantages to that approach?
SS: We know our combo works, and it's kind of nice to know it's a guaranteed deal. It's like buying one of our engines over time. And people make mistakes every day while trying to homebrew.
CHP: For instance?
SS: The mild motors, when properly put together, can actually run lower compression and still make more power, because the parts are happier.
CHP: You also mentioned your 582/745 hp Big Dawg engine.
SS: The 582 is a tremendous motor. It's for guys who want maximum power but can't fit a tall-deck motor under their hood. That's what they want; it has to fit under the hood.
CHP: Does it sell well?
SS: Yes, but the 540 short-block outsells it five to one. A set of 396 oval-port heads will bolt right on, and it's physically the same size as a 396. It looks like a regular motor. That's the sleeper...the hot ticket.
CHP: You use a lot of different engine blocks. How do you decide which one to start with?
SS: The Gen VI is perfectly acceptable for all 540s. If they're using a power adder, people are better off getting a Merlin block.
CHP: What about some of the aluminum blocks you employ, such as the Donovan?
SS: Well, it saves weight and runs cooler, and they're much easier to repair, which is good for racing engines. But in a street car, it's just a cool thing to have.