Painless 60608, Installation Manual

Page: 6 / 52

5

Fuel system requirements include a high pressure, 56-60 PSI, fuel pump. The
fuel feed line to fuel rail must be at least -
6AN or 3/8” in size for stock engine,
350-
450HP, setups. If your engine’s output is more than 450HP you should use -
8AN or ½” fuel rail feed line. Walbro manufactures a wide variety of high
pressure fuel pumps and installation kits. They have many internet distributors
including
www.aztpi.com .
If your vehicle’s fuel tank is one with the early small 1 & 13/16” hole sending unit
you have several options of how to upgrade it. One option is to modify the
sending unit yourself by adding a fuel return line. Another option is to replace the
sending unit with an aftermarket one from a company such as
www.robbmcperformance.com . They offer drop in units with a variety of tube
sizes and adapter fittings. The other option is to have a company such as
www.rockvalleyantiqueautoparts.com cut out the old flange and weld in a large
flange from a later model 1984 & up GM vehicle. The larger flange will allow for
an in tank mounted fuel pump.
LS1/LS6 engines have dead headed fuel rails. They require 58 pounds of fuel
pressure. GF-822 is a Delco return type fuel filter/regulator that can be plumbed
in between the fuel pump and fuel rail. It will filter the fuel and maintain 58 PSI at
the fuel rail. Another option is to mount an external bypass regulator such as one
from Aeromotive. Just be sure to purchase a regulator that can handle 58 PSI
and the amount of fuel volume that you need.

LS1/LS6 engine cooling systems have some specific requirements. First, the
lower radiator hose connects to the water neck with the thermostat behind it. If
looking at the front of the engine it is the water neck to the lower left of the water
pump. The upper radiator hose connects to the water neck at the top of the
water pump. Second, the factory coolant thermostat only starts to open at 195
o
F
and is fully open at 210
o
F. Aftermarket thermostats are available that will open at
a lower temperature. Third, these engines incorporate steam tubes that are
plumbed into both the front and rear of each head. They are all tied together and
then plumbed through the bottom of the throttle body and then to the radiator.
Most people remove the throttle body from this coolant loop by connecting the
steam tube outlet, which is located just the lower right of the throttle body and
protruding forward from under the intake manifold, directly to the upper radiator
hose or to an open coolant bung in the radiator. Do not plug off this steam tube,
it must be connected to either the upper radiator hose or to the upper third of the
radiator in order to bleed off any steam that accumulates in the engine heads.
Companies such as Afco
www.afabcorp.com manufacture direct bolt in radiators
that are specifically designed for LS1/LS6 engine transplants. These are ideal
especially since the coolant inlet and outlet are both on the passenger side of the
radiator. By moving the upper radiator inlet to the passenger side the driver side
is opened up to allow a fresh air intake elbow to be routed there.

Coolant temperature and oil pressure gauge senders can easily be connected to
any LS1/LS6 engine. In both engine heads are threaded coolant ports with
Metric 12 x 1.5 threads. The coolant port on the driver side head is utilized by
the coolant temperature sensor needed for the PCM. The port on the passenger
head usually has a plug in it that can be removed and a temperature sender for a