FORM 1316 (REV. C) 06/03
INSTALLATION INSTRUCTIONS
ADJUSTABLE FLANGE DISTRIBUTOR ADJUSTMENT
PROCEDURE TYPE 482, 590, 790 AND 791 DISTRIBUTORS
GENERAL INFORMATION
Adjustable flange distributors allow you to raise or
lower the distributor by moving the flange down or up
the distributor shank so that the distributor drive gear
engages properly with the camshaft gear. Adjustment
is necessary anytime the engine block deck height is
changed, cylinder heads have been machined or
offset, or any intake manifold modifications.
FIGURE 1
mark lines up with the top dead center (TDC) mark on
the timing tab and #1 cylinder is on its compression
stroke.
NOTE: Removing the spark plugs may make it
easier to turn the crankshaft.
Step 2
Remove the distributor cap.
Types 482, 590, 790 and 791 mentioned in this
writing are derived from the particular distributor’s part
Step 3
number (example: 3448205; 3479005). Type 482’s
Loosen the flange and set screws. Slide the flange up
shallow groove on the upper shank of the distributor
the upper shank.
is the stock flange height reference for 265-454
Chevrolet engines (figure 1). Type 790’s and 791’s have
two shallow grooves. The lower shallow groove on the
FIGURE 2
upper shank of the distributor is the stock flange
height reference for Chevrolet V8 265-454 engines.
The upper groove on the upper shank of the distri-
butor is the stock flange height reference for Chevrolet
V8 Tall/Truck Block engines (figure 2).
Align the bottom of the flange with the shallow groove
and tighten the flange screw to position the flange at a
stock flange height reference. Tighten the set screws.
Step 1
Disconnect your ignition system. Turn the engine
crankshaft in the direction of rotation until the timing
TYPE 590,
TYPE 790,
AND
TYPE 791
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