Thanks for your reply.  Access isn't the greatest, but doable.  It is the style with the female round threaded base that's screwed onto a straight pipe, without Base built in.    I figure its the original one that AS used...without the base.

Do you know what the downsides are without the base built in? Potential to break maybe when you're turning the ball valve on/off?

Thanks for your help.   

Hi Guys-  I did find a photo of the transom and it shows "Flatback" (no V)  I would say slightly rounded at transom but not the V.  Small sump on Centerline at transom with 2 through drainholes. Storage under aft end of fwd deck which opens up and out, large enough for spar 6 gallon tank and hoses, etc.  Foredeck opens to anchor and line storage with through hull drain.  Very Tough workable boat,  I like it.  I like that it is way less than $10K.  Amazing that it is 50 years old. 
   So what does that leave me for best power? (Present is 150 hp Evinrude 2 stroke)  Would like to shed some weight aft so the scuppers work.  Many thanks/ Bob

Thank you. I’ve seen those. They could work in some instances but maybe not for shorter screws. I don’t think they take into account enough space for the “clearance hole” in the image above. The piece being fastened cannot be affected by the threads or it will hang up and not pull tight. In any case I would suggest a test piece to make sure you are getting the results you want before you go for a final piece. I do like the taper of these drill bits for the wood screws. Thank you Rick, as always much appreciated input.

I think you're overthinking this - get this set - https://www.amazon.com/FTG-USA-Piece-Pro-Pack/dp/B07FD74M8W/ref=asc_df_B07FD74M8W?tag=bingshoppinga-20&linkCode=df0&hvadid=80401843598485&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=71978&hvtargid=pla-4584001420112281&th=1

A long time ago I decided that ALL VISIBLE fasteners will be slotted oval headed screws. I didn’t think a Phillips in teak was the look I wanted. Little did I know that machine threaded slotted ovals head screws are still readily available however wood screws are not. I had to special order online to get them. Special thanks to Bolt Depot for having what I need and getting it to me fast and easy.
So to help out with proper fastener size selection I created this block so I have a sample size to choose from. Yes, I am aware that not all fasteners pictured are slotted ovals… it’s more just to catalog for me what is available so I can confidently commit to a size. Teak is tricky in that you cannot just screw into it. You have to pre drill all holes to avoid splitting or to even get the screw to go in without stripping the head off. It’s a very hard wood. So with that said you have to commit to fastener size so you can drill the proper size holes and counter sinks. For example, screwing a slat to a larger board… the slat hole has to be counter sunk and larger than the screw so the threads don’t catch it while the board hole has to be smaller than the threads but large enough to let the screw penetrate without splitting. Every screw requires two different sized drill bits and a counter sink to be installed properly. Simple right? Takes planning especially when I don’t want to make a single mistake with teak. Re-do’s will be tragic especially when I start working with the 50 year old Burmese teak I have for later in the project. I’m just getting warmed up repurposing scraps for now. I do not want to be drilling into finished glossy teak either and risk damaging the finish so all holes have to be pre drilled before varnishing. I just wanted to point out what has to go into fastening teak. I learned the hard way so you won’t have to.