Ok here goes....this will be going in a drag car, prob around 300 to 350 hp. Just a fun car, not looking to get into the 9's. Which size flywheel should I use? Its a '68 327 block. Would this be a 153 or 168 tooth? or does it matter? Is that relative to which starter you use? After deciding on flywheel, what size clutch? 10.5 or 11"? Which one for what flywheel? I need a 26 spline, I'm using a Richmond 4 speed, and a hydraulic throwout. HELP!!
In the HP range you are talking about I would go with a good street / strip clutch , something with some good clamping pressure in the 11 inch variety, 168 tooth flywheel will work for this however be sure you have the correct bellhousing and starter snout as they are different between big and small flywheels. Been running a hyd. Throw out bearing in my coupe for years with marginal success. If I had to do it again , I would run a external slave cylinder and a clutch fork.
To try to help figure what you have now, yes it's relative to the starter and you can start there to see what you have. If the bolt's on your starter are straight across it 153 tooth flywheel. If the bolt's are staggered, you have a 168 tooth flywheel. The 327 can use either of these starter's because there is three mounting holes for the starter on the block and only two of the three holes will work on either of the starters.
First thing they are going to want to know before they recommend a flywheel is all the info you left out of this post. How is the chassis set up (tire size, 4 link, ladders wieght distribution), and what does the car wiegh? The ratio spread in the trans you have, and the rear gear will be next.