I have a 1989 camaro RS 305 LO3 700r4 trans and I want to do a swap and put a 5.7 engine in my car... but I have a big problem I have the 5.7 engine but is another junk... The 5.7 engine it's an L65... with four speed manual trans..... According to what I found The L65 have 145 horsepower 250 Lbt And my LO3 have 170 horsepower 255 Lbt Y have to dogs If I do the swap I cant perfomance de engine L65 put imca heads with big valves , 280 roller cam , headers and a 600 holley carb.. And make more horsepower... but I need to know if it's a good idea or better I modify the lo3

 

The 5.7 (350cid) engine has more potential, the 305 is a boat anchor.

 

To explained a little on what Y2k said. The 350 has potential. The 305 was a redesign casting with the primary factor being weight removal. You can make a 305 powerful but you can't make them strong. What is killing the HP of the 350 is low compression. You can really wake them up with a modern set of Vortec heads off a 90's 350 truck engine. You will need to research it, getting to 350 WHP will be tuff with those dished pistons but 300 hp should be possible with the right cam and intake and maybe a little machine shop work.

Edit,
Something to think about. If you keep the 350 in the 275-300hp range you can put a T-5 from a early 90's 305. Third gen is the lightest of the Camaros. A 300 hp 350 with a 5 speed can be a fun car. You sure would not want to use it as a drag car (neither the rear or trans would like that) but it could be a fun budget road racer.