Need some advice

[Blue Rust]

Ok i picked up this jeep right after new years the guy only used it for hunting and just towed. Its a 76 cj with an AMC 258 strait its not the original moter it was pulled out of another jeep the engine is a 80'. It has a 3 speed trany on it with a backwards H. I have already replaced all the major problems when i bought it. I took it down to a local buddy of mine who replaced the front and rear axles along with a rebuilt carb. It seems to be running very rich and backfireing a lot? i dont know y though. My main though is wat kind of moter would i be better? Sticking with the inline or going to a V6 or V8? I am just starting into jeeping and would be greatful for all the extra advice. I will post pics asap so u can get a look

 

[Blue Rust]

This is wat the jeep looks like

 

[Blue Rust]

This is wat the engine looks like

 

[B192734]

Those inline motors are generally very reliable. Get quite a lot of miles out of them.