Cam Installation Notes
To install your new cam, follow the instructions in the Model T Ford Service Manual. However, there are some minor differences and some checks you should make during the installation.
1. The valve clearance should be 0.010. If you time the valves by piston position, make sure all valves have a clearance of at least 0.008. Also, the cam timing is slightly different from stock, so the piston positions will be slightly different.
2. These cams require the later style short front cam bearing. Be sure to install the bearing with the radiused lip against the flange.
3. When you install the cam, lubricate the bearing surfaces with motor oil and the cam lobes with a moly grease.
4. The base circle of your new cam is a little larger than a stock cam and considerably larger than most reground cams. For this reason you will probably have to grind material from the ends of valve stems. If you are using modern keepers, make absolutely sure that the keepers do not protrude beyond the end of the valve stem. If they do, you should switch to keepers that sit further from the end of the valve or cut a new groove in the valve stem. To give you an idea of how much material you’ll need to grind off, the base circle radii are: (a) stock – 0.406, (b) improved stock – 0.432, (c) 280 – 0.457 In. and 0.402 Ex., (d) Laurel-Roof – 0.477 In. and 0.467 Ex.
5. The 280 and Laurel-Roof cams have more lift than a stock cam. When combined with the larger base circle, the increased lift means that the lifter must rise higher than with a stock or reground cam. You should check to make sure that your lifters provide sufficient clearance between the top of the lifter base and the block. With the cam and lifters installed, make sure that the cam turns freely. Also, with the cam at the highest lift point, check that the lifters can still move upward at least 0.010 inches. If your lifter does not provide sufficient clearance, you should switch to lifters that provide more travel, remove a little material from the underside of the block, or switch to a 250 cam.
6. To install the Laurel-Roof cam you must cut notches in the block, so that #1 and #3 exhaust lobes will clear the front and center cam bearing holes during installation (see discussion by Murray Fahnestock. Also, the Laurel-Roof cam requires the use of 1 1/8 inch diameter lifters.