I have a 68 350 engine, automatic. just recently bought the summit gear drive starter, smaller, pulled mine out, original starter, it has a 9 tooth gear, the new starter from summit has a 11 tooth gear. everything I have looked at says it will work. have any of you checked this out? havent counted the teeth on flex plate, pain in the [censored]! but guessing its a 166 teeth.. what ya all think? will it work? been waiting on summit to get back to me.. want to put it back together.

Doesn't matter how many teeth are on the starter as long as they mesh with the flexplate.

The amount of teeth on the flexplate is an irrelevant number.

thanks Jeff, did some more research and it looks like the 9t and 11t will work the same, just bought new headers and mini torque starter from summit, and want to put it back together now.. thanks again

ok, my new summit starter is only 2 wire connection, my old starter is 3 wire connection. what ya do?? stumped

ok, did a little more digging, wires to starter, {original} yellow and red wire connected to start switch,went to S terminal.. a yellow with green stripe wire is hot. went to R terminal... Hmmmm what do I do.. if the yellow and red wire connected to S terminal, and you have your Batt. cable connected to big lug. will it work without this extra yellow with green stripe that is hot that went to R terminal..
is this confusing yet... is for me..

The “R” terminal wire on original is used to supply full 12 V to the coil for original point set up during cranking to start engine. If your car has been changed to pointless ignition you shouldn’t need it.

You must have had some rewiring done to the starter in the past. 68 should have a heavy gauge purple wire going to the S terminal from the ignition switch, and a yellow wire going from the R terminal to the coil. If you still have a points ignition you will have to install a diode between the coil and the S terminal at the starter. That will give you full 12 volts to the coil when starting but stop voltage from the coil to the starter when the engine is running. Or you can hook up a ford style starter solenoid, the better of the two options. But as stated above, if you have an HEI the yellow wire should have been removed when the conversion was done.
That's the way I see it.

Thanks guys, will have to dig into this wiring a little more.., do some eliminating, I did switch over to petronix and got rid of the points. Did i mention, I hate wiring..

Pertronix is a different case than an HEI. Depending on which one you have you may have eliminated the resistance wire or not. If you did replace the resistance wire with an ordinary wire, as one does with an HEI conversion, then you wouldn't need the yellow wire. If you have the type that just replaces the points, nothing else, then you still need the resistance wire and may still need the yellow wire for starting. May have to contact pertronix to find out. If you still need a full 12 volts at the coil during start, then the diode wire or a starter relay would work.

update. got 1 of my new headers installed. working on starter issue, ordered the hi torque mini starter with the headers from summit. but the starter is not right, the starter gear just touches the flex plate gear, sent it back and they sent me another one, same thing, need to shim it back away from flex plate, like shims inbetween starter and mounting block on starter..

Mine came with a selection of shims, not a summit starter. I did bench test mine before I installed it, once the gear moved out it wouldn't go back in, doesn't affect the operation as the spinning flywheel assists with the gear returning to the 'park' position. Make sure your gear is all the way in before you shim.

sending the starter back, just not going to work, they sent me a different shim pack to shim it back, but was the wrong shim pack i believe, needs to go back almost 3/8 of an inch.
will look at different options now..