Correct, edited my previous post about the trans crossmember mount. Thanks. Dynaflow starter has a different nose length than the 2 speed/3 speed ST3//ST400. Use the starter that fits the trans.
The 63 engine is fine, just get the crank adapter. The engines are pretty much the same between the 63 and 66. Heads have different numbers but are practically identical .'66 heads use valve seals on the intakes to reduce oil use. Earlier heads can be machined for seals. 64-66 engines have a wider thrust bearing flange on the #3 crank bearing. Not a big deal, just buy the correct bearings to match the year. A wider thrust flange would be better for a manual trans. The rear sump oil pickup is made by Carmen Faso and also sold by Russ Martin. The 50's rear sump pan IS different than the 65-66 GS pan.... drain plug is in a different position, and the 65-66 pan has indents for additional crossmember clearance. I'm unsure if the 50's pan will hit the crossmember on a 65-66 car. While Russ offers a ton of parts for the Nailhead, used parts may be priced on the high side, so shop around before buying. His new parts are competitively priced. Some average prices: 65-66 GS exhaust manifolds can be found for about $250-up. There was a set on here, unsure if they sold. Engine mount frame pads, about $100. Rubber engine mounts, $69 each, but out of stock: https://www.buickfarm.net/37/101/gm-group-0-clutch-engine/p-engine-mount-lh-or-rh-nors Adapter plates, about $150 pair. You can try contacting Doug at the Buick Farm, these items come and go. Board members may have them too, try a post in 'parts wanted'. And the guys on www.65gs.com will be glad to help a 66 guy too! That would be a great place to find these items. It's definitely a do-able swap, you just need to find those tough items at a fair price.
Yes, grind the lip off the 63 crank, install the adapter, and use the '65 flexplate and starter with the st400 trans. The Skylark GS used a smaller torque converter for a higher stall speed. If your 65 flexplate has two sets of converter mounting holes, you can put a smaller converter from a st300 trans from a 300, 340, or even a v6 for a higher stall speed. If the flexplate has only one set of mounting holes, you have to use the larger Riviera converter. Speaking of mounting holes, the crank and flexplate has an extra hole that is not for a bolt.... it's there to ensure the flexplate is properly indexed to the crank. Just match up that extra hole between crank and flexplate. That will ensure the enging balance is maintained.
There's no problem using a '57-'61 rear sump pan. Use the smaller converter as a template & drill the nec. holes. It needs to be lined up accurately.
the adapter plates I would just make my own the templates are on the board here somewhere and it is just a flat steel piece with holes drilled in it. that is a 150 toward something else.
ive seen some off older cars like 322s are oil pans all the same bolt pattern? I'm thinking so since you mentioned 364 but wanted to clarify.
