Carb,engine vibration,valve tick, and transmission problems/

[1976spider]

Hey all,
Around january I purchased a 1976 fiat spider for 900 dollars it had a TON of electrical problems and such, being a fiat.
I got it running, and have since slowly been working out the problems, but I need input on some of the quirks it has.
Carb- PO installed dual idf 40's. okay, i guess, but certainly not tuned. when revved smokes alittle(white). is this okay? also Carb on #4 cylinder hisses, only on this cylinder. what could it be?
Vibration- Has excessive engine vibration and can be felt throughout the car. shifter moves with engine shudders also?idle is very lopey... could it possibly be performance cams or is it engine mount bushings? they look very Old and Cracked.
Tick- has valve tick sound, I know I need to adjust but where the heck do I get shims??
Transmission- Slips out of 4th gear,no grinding, but when held in place 4th gear works fine. what could be the problem?
Thanks for all your input and help!:)

[azruss]

vibration could be from a weak cylinder not carrying its share of the load. Pull each sparkplug wire while the car is running and see how much the idle drops. If you find one that makes no change, then you have your slacker. could be carb balance or lousy compression. hissing could be from a missing idle mix screw or some other such appurtenance. can use a small hose as a stethoscope to find your hiss. shifter wobble can be due to a worn ball and socket. pull the triangular plate on the bottom of the tranny below the shifter to inspect. careful as it is spring loaded. 4th gear is probably a worn 3-4 shift fork.

[1976spider]

Thanks for the advice! When #4 plug is disconnected the idle smooths out significantly
What could that mean?

[azruss]

that is an odd one. this is a wild guess, and i hope someone has a more optomistic idea, as what is going thru my head is not good. My thot is you are getting major vibration with power applied to #4. when the power is off and it is just along for the ride, it is much better. this implies something amiss with the piston/rod assembly. maybe the end cap is loose, piston is cracked, wrist pin is very sloppy. Not sure how you would test for this.

[So Cal Mark]

check the firing order first. If that's good, check for a blown head gasket between 3 and 4

[124JOE]

go thru and snug up all the carb base nuts