captgarys

My son and I are building a 2000 Trans Am as a bracket car. The stock block is ruined. I am considering replacing it with a GM iron block 6.0 p/n 12609999 and would like to know the following:
Is it a drop in with no mods required?
Also will my LS1 heads, intake, 4L60E tranny, stock ECM and crank work with no mods
Will the generator, starter and AC work with no mods
I am trying to use as many of my old parts as possible due to budget requirements

Any help would be appreciated

1lejohn

iTrader: (9)

Everything should work except possibly the flex plate on the 60E. The iron block cranks use a spacer on the flex plate. Not sure if you will need it on the stock Ls crank. You will need pistons to fit the larger 6.0 bore.

64post

iTrader: (5)

Early iron 6.0's (99-00) have a thicker flywheel/flexplate flange by .400", all others after have the thinner flange. You may not have the earlier thick flange as they are far less common. Also, if the 6.0 iron block is going into your Fbody you'll need to drill and tap a 10x1.5mm hole where the upper alternator bracket bolt goes, truck blocks don't have that provision. The 6.0 block is as stout of a foundation as you'll ever find in its price range, can be made into a 408 or more and the block weighs 105lbs or more than your aluminum block so expect a slightly different handling effect. For a dedicated drag race motor, it's tough to beat. Many if not all components inter change with you LS1. Wait....did you say A/C? On a bracket car?

thatoneguybriz

iTrader: (2)

^ Good info. If you are going to stay as stock as possible make sure you use the Gen IV crank, rods, and pistons (such as what would be found stock in an 04-06 LQ4). The Gen IV rotating assembly is known to be pretty robust even under forced induction or nitrous applications.

KCS

iTrader: (20)

Summit has this block listed as a Gen IV block, which has a few differences than the Gen III block, all of which are very well documented on this forum. Mainly the rear cam position sensor has been relocated as well as the knock sensors.

The LS1 crank will fit, but may need to be rebalanced for the rods and pistons. As mentioned, this block will require at least a 4" bore piston which will probably be a little heavier than the 3.898" bore LS1 piston. If you use the stronger Gen IV rods, they are significantly heavier than the Gen III rods in the LS1 so a rebalance will almost certainly be needed.

I have a Gen III 6.0L block in my 2000 Trans Am and every thing bolts up just as it did to the original LS1, however, as already mentioned you would want to drill and tap a hole at the front of the block for the alternator. Some have run without it without problems, but it's really easy to do so I don't see why not. I would suggest hanging on to your old block as a reference for where the hole goes though.