Do all thirdgen cams have the fuel pump lobe? This supposed lt1 cam I got off ebay has basically no fuel pump lobe so I think It might be a lt1 cam. Only reason I dont think it is, is because it has a normal size dowel pin but i also heard some of the lt1 cam pins are normal length...what you think?

 

LT1 cam dowels are longer than the older design SBC cams, since the dowel also drives the distributor. Teh dowel holes are also usually drilled a little deeper, so that sometimes the dowel can be driven farther into the recess like the original SBC.

It should be fairly easy to identify a factory LT1 can from the part number on the nose. Many aftermarket LT1 cams still have the fuel pump lobe (I know Comp does).

You should be aware that there are about six different factory LT1 grinds, so a caliper of 2" micrometer will help identify which one you might have.

 

vader - doesn't the cam gear also drive the water pump? not the distributor? the reason for the longer dowel is because the cam gear also has a drive gear for the water pump.

 

The cam sprocket on an LT1 has a spur gear cut on the rear side. This spur gear drives a mating pinion gear/stub shaft assembly. The stub shaft seals through the timing cover and is connected to the water pump via a close coupling. The cam sprocket and cam nose also have a slightly larger diameter and deeper hole in the cam end to accomodate the distributor shaft. These are inconsequential on a retrofit, since the hole isn't used for anything.

So, indirectly, yes, the cam sprocket does drive the water pump. However, the dowel in the end of the camshaft drives the OptiSpark distributor and times it to the engine.

 

there is no numbers on the ends. Also I was told that some lt1 cams had a normal length pin. The hole for the pin goes all the way to the other side unlike my lo3 cam.

 

ok so like a crank trigger for the opti. understand now.