Hello to all,

Will a 305 drop right in place of a 4.3l v6. What is involved ? Also, It has a 3 speed trans. Would like to go to either TH400 or maybe GL80e? would the TH400 be better for fuel economy?

thanks in advance.

 

Its the 700r4 that is the 4 speed of that era. The 4l80e is electronic controlled not by vacuum.
The engine should swap in unless the motor mounts are different. Otherwise its the same block just longer.
At the end of the day, the 5 litre and 4.3 are not that different for power and torque, and the mileage change after everything will be minor.

 

So I assume that the 700r4 can handle a 305 then? Or would you suggest a different trans?

thank you again for your posts.