For over 50 years the small-block Chevy has been the most popular V-8 engine swap on the planet. We doubt there's a car or truck out there that someone somewhere hasn't slapped a Mouse motor into. Those engines are cheap, available, and easy to modify. Which also means they've become somewhat dull and everyone and his brother has one!
That is, of course, unless you've been paying attention to the new crop of small-blocks that are available in GM vehicles. Since the 1997 introduction of the Gen III LS1 engine, a whole new world of possibilities has opened up. Just looking at the specs and performance level of a Gen III small-block makes even the best of the old 350s seem kinda weak. The new Gen III engines are high-tech powerhouses thanks to their roller cam, roller rockers, deep skirt block with six-bolt mains, coil-on-plug ignition, and sequential multiport fuel injection that gives the smoothest idle and best part-throttle cruising you'll find from any engine. Plus, Gen III engines can be had at an affordable price if you know where to look.
If one of these powerplants sounds good to you, then you need to talk to the experts at Turnkey Engine Supply. Turnkey specializes in late-model GM engine packages and has developed more than 10 different engine combinations, some of which can even be swapped into older 4x4s as an emissions-legal package.
Advance Adapters has jumped on board too and is leveraging its swapping experience to make these one of the best values in crate engines today. We know that ever since we learned about Turnkey's package deals we've wanted to get our hands on one of its iron-block 6.0L engines to repower our '82 K5 Blazer. Follow along and we'll show you how to adapt your 4x4 to accept one of these late-model monsters.
Turnkey Engine Supply
Chevy's fuel-injected Gen III small-block V-8 comes in four displacements: 4.8, 5.3, 5.7 (all-aluminum LS1), and the 564-pound aluminum-head/iron-block 6.0L version we're using. All four versions share the same architecture and external dimensions and are available as crate engines from Turnkey Engine Supply and Advance Adapters. At press time the 6.0L crate engine we selected (392 hp, 426 lb-ft) sells for $5,663 from Advance. Not bad considering a Ram Jet 350 (350 hp, 400 lb-ft) sells for about $5,000 and doesn't include any of the accessories! If you need the swap to be smog-legal, there's also a 6.0L package (340 hp, 385 lb-ft) that Turnkey has developed using a production GM computer and calibration for $6,038.
We felt like hacks doing it, but we modified our new 300mm-bolt circle flexplate to work with our TH700R4's 298mm-bolt circle torque converter by elongating three of the six holes in the flexplate. It may be possible to have someone punch the correct holes in the hardened steel, but we used a rat-tail file and carefully lengthened the holes without making them any wider. After 7,000 miles there's still no sign of cracking.
Gen III fuel-injected engines require 53 to 63 psi of fuel pressure to operate. Turnkey Engine Supply has had good results with an externally mounted Bosch fuel pump in sand rails, but for what we had planned for this engine we wanted to run an in-tank fuel pump. We wanted to bolt in a fuel tank from an '87-'91 TBI fuel-injected Blazer and swap the low-pressure pump for a high-pressure unit (GM PN 25163473). We couldn't find one cheap enough so we modified our original diesel fuel tank with a new fuel pump and strainer for a 5.7L LT1 V-8-powered '96 Chevy Caprice. Orme Brothers brazed a -8 fitting onto the end of the 3/8-inch feed line that goes to the engine and a -6 fitting onto the return line that brings the unused fuel back to the tank. The original fuel-sending unit wiring was used to power the fuel pump, and a separate sending unit was added to the tank when we had it professionally cleaned at a local radiator shop.
At this point our 6.0L bolted in to our Blazer and mated up to our TH700R4, but we still needed to plumb and wire it. Cole let us rummage through his collection of Gen III exhaust manifolds to find a set that would fit in our Blazer's chassis. The set of '98 Camaro/Firebird manifolds (top) worked best for us (PN 12567706 RH, 12559507 LH). Other possibilities include '99-'03 Camaro/Firebird (second from top), '99-'03 C/K Silverado (second from bottom), and '97-'03 Corvette (bottom). These manifolds have 2 1/2-inch outlets that Cole was able to build a complete exhaust off of.
Next month we'll finish up the wiring, fuel, and cooling system installation. And we'll finally get to tell you about that monster Magnuson Radix supercharger sitting on top of our 6.0L. Stay tuned!