Will thisI fuel pump fit in my96 blazer 4.3 vortec?
Spectra Premium SP6012M Fuel Pump Module for Chevrolet/Pontiac by Spectra Premium http://www.amazon.com/dp/B000IYQJ2Q/ref=cm_sw_r_udp_awd_9iXmtb1JQ01ZJ

And what about this fuel pressure regulator?
Delphi FP10075 Fuel Injection Pressure Regulator by Delphi http://www.amazon.com/dp/B000CGI37O/ref=cm_sw_r_udp_awd_DlXmtb1MZ3EM2

 

I went to Rockauto's website to cross reference, yes both are correct for a 96 blazer 4.3 BUT FOR THE 2 DOOR ONLY on the pump, can't see your profile while typing here so I can't tell, just make sure. Not sure about others, but I've had bad luck with aftermarket fuel pumps especially in my 2000 Jimmy 4.3 Vortec and 06' Trailblazer I6, AC Delco all the way or risk changing it again sooner than later. Delphi is good for the regulator as they do manufacture many things for GM. No I don't work for Rockauto nor do I own stock , but they are cheaper than most and will give you many options for perfect no doubt fit, I know many others here will agree.

 

please stick with ac delco/delphi on the pump. blazers are picky.