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Last Update 8-20-23
Tech Tip #6- LT1 and LSx Fuel Line Connectors

The Chevy LT1 (late model injected) engine has turned out to be a very popular choice for Jaguar conversions. These engines make plenty of torque and power, but also deliver great fuel economy as well, and have a very extensive aftermarket parts following.

One key area for installing an LT1 in a Jaguar, or any car for that matter, is how to deal with the fuel line connections. Unlike the earlier TBI and TPI engines, which used more conventional threaded (and O-ring) equipped fuel line connections, the LT1 uses a special push and snap style fitting that is interfaced to unique plastic fuel lines . Jaguars on the other hand still use standard rubber hose connected to the steel feed and return lines on the cars. A very simple solution to this is available from your local Napa auto pars store. Napa sells a set of fuel hose compatible fittings that fit the LT1 engine perfectly, and snap right into place. And even better than that, these fittings include a special removal sleeve, meaning they can be disconnected, by hand, whenever desired (the original GM fittings required a special tool to be disconnected).

The hoses can be attached to the fittings using either crimp on brass sleeves (the preferred method, like done for air hoses- your local hydraulic shop can do that for you), or with special lined fuel line screw clamps- the style that have an inner liner that protects the hose from the serrations in the clamp body (the less preferably route, but the same method Jaguar used originally on their injected engines). The fitting part numbers are 730-4927 (3/8, for the high pressure feed) and 730-4926 (5-/16, for the return line). Here are some photos of the fittings themselves as available from Napa, and installed on a typical LT1 conversion, in this case, my 94 XJ12.

Note- for LSx conversions, these fittings are also used  as they fit the fuel rail and filter/regulator assembly