P-Trap, can I put this in like this?

[Standardairconditioner]

Yup, best to move the furnace venting as #14 said.

 

[MKS]

You may want to look at this.
Maybe a solution for the vent issue. Found on this site.

The p-trap could be attached to the drain directly. The cinder block may need field adjustment.
It could be solvent weld or unions as was mentioned for easy clean out as it is accessible. Joist may need field adjustment for union fitting, minor notch.
If the drain that is made up of many short fittings and is curved is the sink/lav,
and this lav is vented with 2" and nothing else is draining into it.
It maybe possible then to connect the lav drain and the shower drain in the joist cavity then direct them to the three inch drain that a toilet is also connected I guess.
Maybe where the y for the multiple fitting curved drain is.
Maybe down and under the joists to the area of the y the plumber installed.
This assumes that one of the above diagrams fits your particular situation. Could be confirmed here by a professional by asking the right question or questions.
Many 2x8 joists have been punctured/damaged and reinforced by sistering lvl, plywood,steel, glue and screws etc. Avoiding this is best if possible.
Remodeling weeeeee
Drilling through one joist to drop into the three inch drain and reinforcing the joist maybe be an option. It is hard to tell if the three inch drain is tight to the bottom of the floor joists.
Most anything can be moved.
'Can't' meh
No need to yell

 

[Sponsor]

 

[Sjsmithjr]

Can't run drain through the joists, joist are 2 x 8, joists aren't big enough to drill a 2" at least hole through them.

You can bore a 2 3/8" hole in a 2x8 floor joist; that's the same O.D as a 2" Schedule 40 PVC. The hole can't be drilled within 2”of edge of joists.

Max notch for a 2x8 floor joist is 1 1/4" and can not be located in the center 1/3 of the unsupported span.

If you're concerned about the structural integrity of the joist consider "sistering" 3/4" plywood onto the sides attached with construction adhesive and 6d nails on 8" centers. Cut the plywood about a 1/4" narrower than the depth of the joist (e.g for a 7" for a 2x8). Makes it easier to tip into place. Stagger the seams at least 2 feet.

 

[Pitterpat]

The best way will be to notch the joist if needed. Will not drill a hole in the joist, I don't have a drill stout enough to drill the hole and it's not necessary either, the drain pipe isn't that high.

 

[Pitterpat]

The p-trap could be attached to the drain directly. The cinder block may need field adjustment.
It could be solvent weld or unions as was mentioned for easy clean out as it is accessible. Joist may need field adjustment for union fitting, minor notch.
If the drain that is made up of many short fittings and is curved is the sink/lav,
and this lav is vented with 2" and nothing else is draining into it.
It maybe possible then to connect the lav drain and the shower drain in the joist cavity then direct them to the three inch drain that a toilet is also connected I guess.
Maybe where the y for the multiple fitting curved drain is.
Maybe down and under the joists to the area of the y the plumber installed.
This assumes that one of the above diagrams fits your particular situation. Could be confirmed here by a professional by asking the right question or questions.
Many 2x8 joists have been punctured/damaged and reinforced by sistering lvl, plywood,steel, glue and screws etc. Avoiding this is best if possible.
Remodeling weeeeee
Drilling through one joist to drop into the three inch drain and reinforcing the joist maybe be an option. It is hard to tell if the three inch drain is tight to the bottom of the floor joists.
Most anything can be moved.
'Can't' meh
No need to yell

Yelling: I don't think you were listening like you aren't now!

I'm not going to use the diagrams, all I need to do is attach the drain from the shower to the wye where it is supposed to be attached!