Chevy Small Block Dyno Tests - Old School Meets New

406ci Traditional Mouse Vs. Late-Model 402ci LS2

Step By Step

Inside is a complete Lunati LS1 Pro Series stroker kit assembly featuring a 4340 forged crankshaft with a 4-inch stroke, 4340E billet rods, forged pistons, and main bearings. Yeah, this baby isn't going to break anytime soon, and the added rigidity will allow for aggressive testing in upcoming issues. One thing we need to note is that the crankshaft featured a 24-tooth reluctor wheel, which was swapped for a 58-tooth wheel to work with the Edelbrock controller.

Like the LS1/LS6 and LQ9 blocks, the LS2 features a six-bolt main. The inner bolts were torqued to 58 ft-lb, 55 ft-lb for the outer, and 25 ft-lb for the cross-bolts.

One of the biggest advantages of the LS engine is having the ability to swap camshafts with minimal effort. All you have to do is remove the front timing cover, loosen the rocker arms, and slide two rods to support the lifters. Keeping that in mind, we started small with the 230/232 duration at 0.050 (PN XER281HR) and later stepped up to a larger 238/240 duration stick (PN XER287HR).

Turn Key 402ci
For this build I enlisted the help of Turn Key Engine Supply in Oceanside, California, and engine builder Chris Pollock, whom we have to give major props to. Considering our dyno session was scheduled for the following day, these guys had the entire bullet built from scratch to finish in a matter of hours. Then again, when your business is in the habit of cranking out 40-plus turnkey engines a month, it's just another day in the office.

Now I'm not going to give you a history lesson, but I do want to point out that the LS1 first debuted back in '97, and while it may seem hard to swallow, the newfangled LS variants are already going on their 10th year! Point being, it's not that new, folks. If you aren't familiar with the 6.0L LS2, don't sweat it. It's still in the same platform as the Gen III LS1/LS2 and the 5.3L and LQ9 6.0L truck engines. Matter of fact, all the parts available for this engine family are interchangeable, and it closely resembles the LQ9 truck motor, with the exception of its aluminum construction over the cast iron. Other differences include the relocation of the cam sensor from the rear of the engine to the front and the loss of dual knock sensors in the valley pan, which are now located on the side of the block.

Getting on to the mule, the initial plan was to build on a cast-iron LQ9; however, after pricing out bare blocks, we learned that the aluminum LS2 was only $300 more. Given the similar construction, it only seemed fitting to try something new. Besides, a motor that weighs significantly less only adds to the cool yet functional factor when dropped in between the fenderwells of any street machine. I'll let the following pages reveal the sordid details, including the price breakdown, the components used, and the dyno results.

If you're curious as to my interpretation of this month's test, I will say that the overall results left a permanent impression. Considering the LS2 churned out well over 560 hp and 520 lb-ft with excellent idle quality at 13 inches of vacuum, it's a true driver. And yes, that's on 91-octane. As an added bonus, we swapped the camshaft and went up another 8 degrees of duration, improving on our numbers with over 580 hp and 530 lb-ft, all the while maintaining 10 inches of vacuum at idle. As for the older Mouse, it was impressive, to say the least, but it's far more aggressive and lends itself as more of a weekend brawler when compared with this LS2. That said, dollar for dollar, at least in this comparison, the 402 LS2 proved that it can not only produce serious power, but with a relatively mild build it's perfectly suitable for the street. I'd like to see what this combination could produce with a stout solid-roller, but that's a story for another month.

0701ch_04_z Chevy_small_block_dyno_tests 4/41

Unlike the 406ci, we produced 583 hp and 530 lb-ft on 91-octane and through the mufflers.

Peak power was had with a 72/79 jet combo through a 750-cfm Mighty Demon.

We used 13⁄4 Hooker long-tubes with mufflers for every pull.

The front timing cover, oil pan, and valve covers are all factory issue.

Turn Key offers this trick-looking balancer for $280.

Bare aluminum LS2 blocks can be had for only $995.

Dart 225cc Pro 1 LS1s are true bolt-on pieces and retail for only $1,620.