Sometimes a good story has no romance—no big horsepower or awe-inspiring torque. Some good stories are all about the details that the big-power stories overlook. But if you play with engines like we do, it takes about three seconds to realize that commanding the details is a good place to start. Assembling an LS engine is all about finding all those little parts and installing them properly. Mess up even one little detail and the experience can become troublesome and downright exasperating.
Unlike the small-block Chevy that has experienced relatively few updates over its six decade-long life span, the LS family is approaching 20 years old yet is already on its third significant revision. The original Gen III engines, first available in the Corvette in 1997, were updated roughly around 2005 as the Gen IV and now the Gen V direct injected (DI) engines have arrived. This story will focus on the Gen III and Gen IV engines, as the DI engines are only now beginning to show up in aftermarket performance applications.
The main focus of this story will be on identifying most of the small parts and their part numbers you will need when assembling an LS engine. For example, if you were to buy a bare, iron 6.0L block, like the Summit-machined piece that is a great deal, then you are going to need many of the numbers included in this story. A few companies are helping by including a few of the essential parts in their kits. Summit, for example, sells a small plug kit that combines a few of the little parts that you will never find at your local auto parts store. So while a list of part numbers might not be very glamorous, copying this list and putting it in your toolbox lid or in that special spot where you can find it quickly might be a move that will save you a lot of time searching for the one little oil galley plug you need to complete that engine.
In many ways, assembling an LS engine is much easier than its predecessor small-block, but only if you have all the right small parts.
In the Chevrolet Performance catalog, they list all these parts under separate part numbers as the Gen III bare-block completion kit. All of the PNs in the list are included in this article. Summit offers a small parts kit that includes the large brass coolant drain, the small press-in oil galley plug, the three medium block plugs, and the barbell. That’s under PN SUM-G1584.
You don’t want to forget this little oil galley plug at the front of the block. It’s located behind the front cover. If you leave it out, the engine will not make oil pressure. You can find it at Summit Racing under PN 9427693 for less than $4.00.
This little oil diverter valve is located at the back of the block and is often called the barbell because of its shape. This valve is essential to the oil pressure circuit. You can buy it separately under PN 12573460 from Summit Racing for less than $7.00. The O-ring seal goes to the outside, as shown.
There are three external block plugs of the same size for the Gen III/IV blocks that are a little confusing. The photo shows one plug installed in the oil galley on driver-side front. On the passenger side toward the rear, a similar plug is used as a coolant drain.
If the LS engine’s head-locating dowel pins look suspiciously like big-block Chevy dowels, it’s because they are very similar. In a pinch, you could use BBC dowel pins in an LS as they both measure 0.638-inch OD.
LS Engine Small Parts List Description PN Source Front cover, LS1, no seal 12561243 Summit Racing Front cover, LS2, w/ sensor 12633906 Summit Racing Rear cover w/ seal 12639250 Summit Racing Cam retainer plate – req. button head bolts 12589016 Summit Racing Cam retainer bolts, button head, need four 11561455 Summit Racing Coolant plug (large), driver-side rear 12561663 Summit Racing Coolant plug (large), driver-side rear 11609289 Summit Racing Coolant and oil plugs, ea., need three 11588949 Summit Racing Barbell oil plug for rear of block 12573460 Summit Racing Summit LS plug kit SUM-G1584 Summit Racing Front oil galley press-in plug 9427693 Summit Racing Cylinder head dowel, need four 12570326 Summit Racing Bellhousing/trans dowel, need two 1453658 Summit Racing Crank sensor, 24X LS1 - black PC123 Summit Racing Crank sensor, 58x, LS2 - gray PC552 Summit Racing Cam sensor, LS1 and truck, black PC273 Summit Racing Cam sensor, LS2 front cover style 213-3826 Summit Racing Oil pump pickup O-ring, blue, 23.6mm ID 12557752 Summit Racing Oil pump pickup O-ring, red, 20.7mm ID 12584922 Summit Racing Fel-Pro head bolts, TTY, 1st design, 1 side ES72173 Summit Racing Fel-Pro head bolts, TTY, 2nd design, 1 side ES72390 Summit Racing Lifter guide, all Gen III and IV, ea. need four 12595365 Summit Racing Lifter guide bolt, (ea.) need four 12551163 Summit Racing LS6 valley cover 12568002 Summit Racing LS3 non-AFM lifter valley cover 12598832 Summit Racing Dorman LS1/LS2 front cover 635-515 Summit Racing Coolant drain plug M28 11609289 Summit Racing LS1/LS2/LS6 cam bolts, hex, 1/pkg. 12556127 Summit Racing GM LS2 cam gear, four pole, 58x style 12586481 Summit Racing GM crank gear 12556582 Summit Racing GM HD timing chain, single row 12646386 Summit Racing GM oil pump (ex. LS7, LS9) 17801830 Summit Racing Fel-Pro Front cover gasket set includes oil pump seal TCS45993 Summit Racing Summit LS rear main seal housing SUM-G2621 Summit Racing Summit main cap bolt kit w/ freeze plugs SUM-G1585 Summit Racing Oil pan, front and rear cover bolt, ea. 11515758 Summit Racing Summit oil pump, std. volume /pressure 121170 Summit Racing
