How to Swap in a Carb-Equipped LS Engine

Carb-Equipped LS Swap 101 - Want modern LS power but without the hassles of retrofitting fuel injection? We show you how.

Patrick Hill Jan 28, 2014 0 Comment(s)
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1987 Caprice LS Swap Flywheel 2/39

11. The solution is this GM flywheel spacer (part no. 12563532- $54.69) and flywheel bolts (part no. 11569956 - quantity 6, $3.47 each). This plate makes up for the thickness difference between the LS flange and the old Gen I small-block flange. It also keeps the torque converted centered on the crankshaft.

SUCP 140100 SWAP 013 3/39
1987 Caprice 5 3L LS Dropped 4/39

12. With everything ready, the 5.3 is dropped into the Caprice. It was amazing how easily the LS-based motor fit into the space where the 305 used to be, and even gave us some extra room in the engine compartment.

Hooker LS Swap 5/39

13. The factory exhaust manifolds on the 5.3 won’t work in this setup because the outlet is in the wrong place. The easy solution were these Hooker conversion headers for a second-gen Camaro, part no. 2471-1HKR. The car already had a dual exhaust system in place, so all we had to do is trim the pipes back to mate with the headers, and viola!

1987 Caprice LS Swap Header Bellhousing 6/39

14. We did run into one problem, though. The driver’s side header hit on this ear on the transmission bellhousing.

1987 Caprice LS Swap Trim 7/39

15. Another easy solution: We just cut the offending ear off. After that, the headers cleared with no problem.

1987 Caprice LS Swap Holley Accessory Drive 8/39

16. With the engine in place, we could start bolting on the accessory drive using Holley’s accessory drive brackets. First up was part no. 21-3 for the alternator. The bracket is a two-piece design that bolts to the front of the block on the driver’s side. The alternator is a standard late model unit, part no. 01-1748X, from O’Reilley’s Auto Parts.

1987 Caprice LS Swap Holley A C 9/39

17. Next is the bracket (part no. 20-131) for the AC compressor. The Holley bracket uses the same R4 radial compressor the Caprice came with stock, except it relocates to the passenger side. Because we’re converting from V-belts to a single serpentine belt, the compressor for an ’88-’95 V-8 full-size Silverado is used.

Edelbrock Performer RPM LS1 Intake 10/39

18. The intake we’re using is a dual plane Edelbrock Performer RPM LS1 (part no. 71187) that comes with a dual bolt pattern to fit either Edelbrock or Holley flanged carbs. For ignition, we’re using MSD’s stand alone LS1/LS6 ignition controller, part no. 6010. It’s designed to just run the factory LS coil-on-plug ignition, using the stock crank and cam sensor.

1987 Caprice LS Swap Throttle Tv Cruise 11/39

19. Because we’re using a carb, the Caprice’s factory throttle, TV, and cruise control cables can still be used. This new cable bracket came with our intake, and installs like so.

1987 Caprice LS Swap MSD Ignition 12/39

20. The MSD ignition controller is an almost entirely plug-and-play unit. The simple harness it comes with has one master plug that bolts into the control box, then eight plugs that run to the ignition coils, plus one to a MAP (Manifold Absolute Pressure) sensor in the intake.

1987 Caprice LS Swap MAP 13/39

21. The Edelbrock intake already has provisions to mount the MSD MAP sensor here. A MAP sensor measures the vacuum pressure inside the intake manifold, and along with the RPM reading of the engine, tells the ignition to either advance or retard the timing.

1987 Caprice LS Swap Ignition 14/39

22. To power the ignition, this main pink wire from the new ignition harness is run to the pink wire on the factory coil plug. This supplies the ignition with key-on power.

1987 Caprice LS Swap Radiator 15/39

23. For the cooling system, you can use the stock radiator. First up is a new upper radiator hose, Gates part no. 22436, which is spec for an ’99-05 4.8/5.3 Silverado.