Engine bay limitations

Once beyond the issue of whether the engine actually fits into the engine bay (and the Chevy LS3 does fit), fitment research must expand to the so-called front drive accessory system, a pulley array that rotates the water pump, alternator, power steering, and air conditioning accessories.

The overall dimensions of the XJ6 chassis depart significantly from American cars of the same era, so Ford and Chevy swap specifications can’t be used. The Jaguar engine bay we have to work with is roughly 19 x 34 x 44″ as shown below.

Stripped and blasted chassis reveals overall dimensions of XJ6 engine bay

The engine bay shapes are complex and difficult to visualize (and measure!). A reasonably accurate CAD drawing with a Chevy LS3 engine block shows some of the clearances.

LS3 front view in engine bay

LS3 top view in engine bay showing part of transmission

 

Front drive options

Front drive systems come in integrated packages with components and brackets that are designed to work together; in addition, individual accessories can be selected to mimic now out-of-date configurations. It is also possible to engineer a custom system from scratch (this may require the fabrication of special brackets). The custom approach is really a last resort if none of the integrated packages can be made to fit.

There are five basic integrated options:

  1. Chevrolet Performance (CP) Corvette LS3 front drive (~$850)
  2. Vintage Air Front Runner (~$2800)
  3. March Performance narrow mount front drive requires new water pump and special mounting bolts (~$1500)
  4. Holley high mount (~$1300) and new mid-mount front drive (~1800)
  5. Vintage Camaro/Firebird 1998-2002 (similar to 2004-06 GTO) – no package available so must be assembled from individual parts, but system itself is an integrated design

CP CORVETTE LS3

CP LS3 Corvette front drive with alternator mounted high on the left

2007 LS3 Corvette front drive (2018 CP version differs slightly)

2007 LS3 Corvette side dimensions (2018 CP version differs slightly)

CP LS3 Corvette dimensions

VINTAGE AIR FRONT RUNNER

Vintage Air Front Runner has the most compact footprint

MARCH PERFORMANCE

March Performance is similar to the Camaro/Firefird layout (perspective not full front profile)

HOLLEY

Holley high mount option places A/C pump and alternator up for low clearance

Holley high mount front accessory dimensions

Holley mid-mount with compact profile (new in 2018)

CAMARO/FIREBIRD 1998-02

Vintage Camaro/Firebird design requires some remanufactured parts

Costs and components

Front Drive Comparison
System P/N Cost Amps Comment
Corvette LS3 19155067 $830 150 water pump P/N 89018052 not included – damper P/N 12620556 recommended
Camaro/Firebird various $2025 105 assembled from individual parts
Vintage Air 174011 $2780 170 includes water pump and balancer
March Performance 19925-08 $1350 140 includes water pump but no balancer
Holley 20-138 $1290 130 high mount may require bracket kit
Holley 20-185 $1800 150 mid-mount includes all components including belt

If it fits, the Corvette LS3 from Chevy Performance is the most cost-effective solution.