I'm building a stroker motor using the block # 10105123.

My L98 stock starter does not fit. The bolt holes in the stroker block are diagonal, while the starter motor off of my old L98 are space straight across.

What starter motor can I buy from a Chevy dealership or Summit Racing which will fit the 123 block?

 

You'll probably have to keep the L98 starter and just drill and tap a new hole in the block, like I did.

 

Well, the engine is all built. I could not put the block into any kind of a mill or drill press. The extra hole has to be drilled very accurately. I'm not sure that would work out for me.

BTW: The flywheel has 153 teeth.

 

It is not possible for a starter with the diagonal bolt pattern to fit a 153-tooth 12.8" flywheel. The inner bolt, the one closer to the crank, is correctly located for a 14" flywheel. But since the starter shaft for the smaller flywheel has to be about 5/8" closer to the crank, the inner bolt hole of the pattern for the larger starter would go RIGHT THROUGH THE MIDDLE of the starter drive.

Bottom line: the ONLY solution is to either drill the right hole, or change to a 14" flywheel / flex plate.

 

OK, lets say I attempt to drill and tap this hole.

The bolt is 3/8" NC16... I do have a tap & die set,,, I've confirmed that I have the correct tap (the bolt screws into the matching sized die).

The hole diameter that I need to drill I believe is 0.300"...

Is that correct? What numbered drill is this? I will have to go out and buy a good hand drill (my 3/8 7.6V hand drill wont do) and a numbered drill set.

 

The correct drill size should be written on the tap. If not, do a google search or something, it's very common knowledge, and easy to find a table.

Notice that the hole is a special hole; the threads are about 3/8" deep down in it, and the upper part is larger. Starter bolts have a larger diameter section behind the threads that fits into that, and a corresponding fit into the starter nosepiece, that acts like a dowel pin to locate the starter positively.

 

Call Summit. I did and got a Proform starter that can be mounted 18 or so different way and got ti to work on my late 70-s block in my 383 with a 153 tooth T5 flywheel.

 

same here, my mini starter mounted right up, I used the same one on my 14 inch flexplate that I did on my 12.8inch flywheel, just had to move it over to the next mounting hole on the starter.. defently not possible with any factory starter that I know of however...

 

Doesn't matter what starter you use, if you don't have the bolt hole, it won't work with the small flywheel. The inner bolt would have to go RIGHT THROUGH THE MIDDLE of the starter drive.

Late 70s blocks often came with the late-model bolt hole. Blocks before about 78 did not.

Don't believe that just because somebody else bought whatever part # starter and it fit their block, that it will fit yours. You have to have the right inner bolt hole.

The 18 different way thing has nothing to do with the location of the starter shaft. All that does, is to allow the starter body to be rotated, to get clearance between it and headers or oil pan or whatever. The shaft always stays in the same place, as it would have to, since the starter has to be the right distance from the flywheel and rotating the starter motor doesn't move the flywheel around somehow.

 

ditto on the proform ministarter. it has a universal mounting plate with almost every bolt configuration you could imagine. besides that, i have never had the solenoid heatsoak and leave me stranded since i switched. with the stock starter it ate solenoids.