Although GM has been building and selling crate engines to the general public for years, many of its offerings have hardly been what we'd call "High Performance." Sure, they were good engines. But what they had in quality, they lacked in gusto. Not anymore. GM Performance Part's (GMPP) newest line of crate big blocks is a classic example of racetrack power transcending to the street. We're talking about GMPP's two new big-block Chevy crate engines. Each totaling 572 cubic inches with one for the street and one for the track, or maybe two for the street if you're not against lashing valves and driving around breathing race gas fumes.
The coolest things about either one of these crate engines is that after you've bought one, you don't have to do a thing, that is, except to drop it in your car and fire it up. They come delivered to your door already broken-in with all the necessary fixin's to get you under way. There's very little else you'll need to buy to make these beasts run. Of course, you'll need the standard items like fuel and oil, but you won't have to buy spark plugs or ignition cause it's already in there. Also, both of these engines come with roller cams; a hydraulic roller in the street engine, and a solid roller in the race engine, so there'll be no cam break-in needed either. Both engines even come with their own carb that's already dialed in. Although you may have to adjust it some, depending on where you live and your local weather conditions. But for the money, these things are really hard to beat. And don't think for a minute that these engines are some old rebuilt Rat motors. Every part used in these beasts is 100 percent new and very heavy-duty to boot.
When GMPP set out to build the baddest crate engines around, they sparred no expense ensuring that the engines would live to fight for a long, long time. To that extent, GMPP equipped both big-blocks with 4340 forged steel cranks and rods. Forged aluminum pistons with full-floating wrist pins were also included, 9.6:1 compression for the street motor and 12:1 on the race version. And both engines have roller cams for power and durability. On top of that GMPP installed a new version of its proven rectangle-port aluminum cylinder heads, and then cast up a special single-plane intake manifold to fit the tall-deck Bowtie Sportsman Gen VI block. And to make sure there'd be no chance of any one of these engines not making the power they claim, GMPP installs its own specially made Demon double-pumper carb and a hi-perf HEI complete with wires and AC plugs.
GMPP even puts the spark plugs in. Check out the healthy D-shaped exhaust port too. | 
A pair of 2-inch Hooker headers mated to 3.5-inch Dynomax Race Magnum mufflers, (neither are included with the crate engine) handled the exhaust duties. Who'd thought you could make so much power with such relatively small headers and mufflers? You might want to think twice about running a 4-inch exhaust on your small-block next time. | 
Here's all the tuning we had to do to make over 700 hp. The specs called for between 34 and 36 degrees total advance, so we set it at 35 and walked away. |
There are some extra bonuses that come with buying GMPP's biggest crate engine. The block comes drilled for a remote oil cooler and/or remote filter. Ours came equipped with a new AC oil filter screwed onto the stock location on the left side of the block. The braided line you see is for reading oil pressure on the dyno. | 
And speaking of oil... GMPP ships the engines "dry" and recommends 20W-50 motor oil. The system capacity is 7 quarts. | 
We like the GEN VI big-block's cast timing cover and the built-in pointer it features. This crate motor also came with an SFI-approved Fluidampr harmonic dampener. |
Unlike the previous GEN V blocks, the GEN VI versions feature a fuel pump mounting boss. They also feature the newer-style one-piece rear main seal for no oil leaks. But that means they require a specific oil pan and crank, which GMPP installs. | | |