Here is what the stock 1965 & 1966 Ford Mustang Vacuum Lines for a C4 Trans and a stock Load O Matic Distributor would look like for reference if you remaking them or re routing them as well as the Fuel Line from the Fuel Pump to Carb. The C4 Vacuum Line has a mounting clip on the top bolt of the Tail Housing (on the Passenger side of the Car that the Vacuum Line Clips into and hold it securely is probably still on the trans. There should also be another one too I think it may be on the top Bell Housing Bolt or else on the back of the engine for front of the line to Clip into. Good luck.
1965 & 1966 Ford Mustang 200 Six C4 Vacuum Line to Modulator
https://www.cjponyparts.com/classic...ne-original-steel-6-cylinder-1965/p/MUM1001O/
1964-65 FORD MUSTANG DISTRIBUTOR VACUUM LINE SET Distributor Vacuum Line SKU: MUA1001-S https://classictube.com/product/for...line-for-the-6-cylinder-170-200-cid-19641965/
Classic Tube Fuel Line Pump To Carburetor Original Steel 170/200 1965 Classic Tube:MUC1001 OE https://www.cjponyparts.com/classic-tube-fuel-line-pump-to-carburetor-original-steel-170-200-1965/p/MUC1001O/
1965 & 1966 Ford Mustang 200 Six C4 Vacuum Line to Modulator
https://www.cjponyparts.com/classic...ne-original-steel-6-cylinder-1965/p/MUM1001O/
1964-65 FORD MUSTANG DISTRIBUTOR VACUUM LINE SET Distributor Vacuum Line SKU: MUA1001-S https://classictube.com/product/for...line-for-the-6-cylinder-170-200-cid-19641965/
Classic Tube Fuel Line Pump To Carburetor Original Steel 170/200 1965 Classic Tube:MUC1001 OE https://www.cjponyparts.com/classic-tube-fuel-line-pump-to-carburetor-original-steel-170-200-1965/p/MUC1001O/