89 chevy s10 blazer puff smoke out tailpipe when 1st started

Check for rust inside distributor under rotor.

You could pull the trans pan and remove the valve body, and clean.

Not the converter,it is there to build pressure, to supply the valve body and apply fluid to clutch drums, that apply pressure on the clutches for each gear.

If you do remove the valve body to clean, you will need a picture of where the check balls go,when you replace it. Put assy trans lube or vasoline on balls to hold in place. Your working upside down unfortunately.

If the shift valves are free,no sediment, your out of options, unless a servo valve is hung up and doesn't apply a band. They out it comes,and you take it apart,to find the issues

Don't recall solenoids,other than for converter lock-up, back in 1989. Someone else may add to my theory.

Adjust the idle though the throttle body at the top

my 89 s10 blazer's air conditioner compressor clicks on an d off...what is the problem?

That would be a hanger bearing holding up the rear of the drive shaft

This is Due to VALVE STEM SEALS Leak Down Replace them And this BLUE Smoke will Stop Chevy is Pretty Well Known For this Premature Failure of the Stem Seals, I Have Done this Repair Many Many Times.

It's not worth doing all that conversion, buy the time you spend the time and money to convert the 89 4.3 to work on the 98 blazer, it would be cheaper to install a 98 vortec rebuild. The 89 4.3 have a TBI fuel injection system and the ecm on the 98 will not work and the bad news is that the ecm on the 98 also controls the transmission shift points and the 89 will not, so even if you swap the ecm to have the 89 4.3 engine work. the transmission will not shift. Sorry for the bad news but it would be cheaper to replace the 98 engine with the years of 1996 to 2001. Good luck and hope this helps. 

you must have not connected a ground wire when you put the pump back on.

look at the drivers side rear of the engine next to trans

have someone check the starter/solenoid