i can only assume you mean a LT1 350 and the 4.3l is actually like a little brother to the 5.7 LT1 it uses alot of the same parts internally and externally i have heard a bunch of times that they...
Yes, but you will need to change the prom in the computer and you may need to make adjustments to the fuel system to compensate for the larger fuel injectors.
yes it will fit may have diffrent window trim and you will have to use your door panel if it is a front door you will have to change mirror also u will need to change your handle your 91 should be...