Civic EG

just enquiring is it worth my time swapping a d15b7 engine to a d16y1 if so how much do i have to change over from the d15b7 i drive a 95 EG8 civic with automatic transmission or am i better off trying to source a d16z6 motor only enquiring because my d15b7 blew a head gasket for the 2nd time in 6 months and thinking that replacing the motor would be a viable option

No one ever replaces the head gasket properly so they blow again pretty soon after.

Not sure what the D16Y1 is but it's probably OBD2. I would suggest getting an OBD1 replacement ie the JDM D15B, a D16Z6 or its JDM ZC equivalent. Even better would be an OBD1 B18B.

Here's what I found online:

D16Y1

Found in :
1992–1995 Honda Civic VTi (AUS)
Bore and Stroke: see D16 Series Engines
Displacement: see D16 Series Engines
Compression: 9.3:1
Power: 129 hp (96 kW; 131 PS) at 6,600 rpm
Torque: 107 lb·ft (14.8 kg/m, 145 Nm) at 5,200 rpm
Redline: 7,200 rpm
Valvetrain: SOHC VTEC (4 valves per cylinder)
VTEC Switchover: 5,000 rpm
Fuel Control: OBD-1 MPFI
Head Code: P08
ECU Code: P28

So it looks like your D16y1 is a lot like our D16z6. You could do a mini-me swap or replace the whole engine.

lets say i do a complete swap over what would i have to replace besides the ecu would the auto gearbox i currently have have to be switched over also

this may not be related but how much effort is involved in changing a d15b7 to a d16y4

The auto tranny will work. You'll need the correct ecu (p28 auto I'd guess) and the wiring for the vtec head. (2 wires to the ecu, 1 ground)

with a complete swap would i have to change the driveshafts intake manifold loom etc

driveshafts will be the same for both.
Both are OBD1, so intake loom will have the same sensors.
One thing to check for is that both your car and the donor car have the MAP sensor in the same place. Some cars have it on the throttle body and others have it mounted to the firewall. Going with the same setup as your current car will save you some custom wiring headaches.