Hi SPlDEY, I only can give you a feedback of my opinion and taste because I dont know what you are trying to achive in the end.
Composition wise this Songs is great, even if the vibes part is not in tune and sounds to me like thrown into the mix from a record.
I only can criticise the sound. To me it sounds to clean and there for to much like a demo recording out of the bands practice room.
I dont know which and how many mics you used for the individual instruments, but I always worked with the technics which Gabriel Roth of Daptone records fame once published.
Using only shitty dynamic mics, no condenser mics because the are sounding to nice in certain frequencies. For the drums I only use 2 mics. One for the Bassdrum, the second for the snare and Hihat. If you want to be even gritier just use one mic for the drums.
To achive the nice 70s shitty funk 45 sound, try to experiment with mic positions. A inch more to the right or left can be the difference between a dope sound and a boring sound.
BUT, only in combination with tape saturation !!!
As far as I know your Tascam 388 got REPRO, that means you can listen off of playback. This way you can check out the amount of saturation in combination with mic positions.
You really need to go into the red to get nice saturation, and you need to EQ the bassdrum and bassline down before hitting the tape, I needed to turn down the bass frequencies - 12 db, because the bass will be boosted back by the tape.
You will also hear that a hihat or cymbal which was not loud enough on your original recording, will be boosted too and will sound very loud.
The saturation compreses all the small sound informations like sqeaking bassdrum pedals or the resonance of screws and bolts of the drum and all the parts of the drum which can swing, but you can not hear on a modern day recording. Thats the reason why an old drum recording sounds so large in comparison to modern day recordings.
The same goes for all electric instruments, accept that if you want it, you could manipulate these instruments later, if you would use a PC at the end of multitrack productions.
For example, your guitar sound is to nice and to modern sounding to me. You could record it on tape and after digitalising all multitracks into a multitrack program like cubase, logic or whatever you could than use plug ins like NI Guitar Rig on the guitar track. There you can manipulate the sound into a more shitty 70s direction. The same goes for Fender Rhodes, Vibes, old Moog Synths and so on.
Another important sound part of old recordings are the effects.
For example your drums are very dry, even if you work with saturation, sometimes more room is needed to sound old. Try a spring reverb on it. Gabriel Roth says only a real sping reverb is nice, but to me the waves spring reverb plug in sounded as nice as the original, except for the static noise of my spring reverb tank which I sampled over my digital spring reverb.
Reverb and echo are very important on all tracks, especialy on vocals, guitars and horns. The more you can hear the effects on tracks the older it will sound, because today effects are used in very small ammounts.
If you are interested in thos Gabriel Roth articles you can get them here as PDF files:
This one is about composition and the players.
http://westtownrecording.com/wp-content/uploads/2010/05/shitty11.pdf
This is all about recording.
http://westtownrecording.com/wp-content/uploads/2010/05/shitty2.pdf
Here is a recording I did with all I talked about.
Imperial Breed - Horny Pipin Beats (Juice Exclusiv… - MyVideo
Peace
Hawkeye
