Respectfully. ...buying an 89 truck....you might want to own a gas company nowadays...

 

I have an AOD its a 3 speed with overdrive.

 

My truck already gets around 10-12 mpg.

 

With a 351C you will never seen double digits again.

 

Maybe 10 if you're lucky. ..

 

Look - if you do the sixlitre tuneup to your 302 without doing anything else your power and gas mileage should be better. You are just starting out - start small and work your way up.

Of course, you should attend to other required maintenance and adjustments. Optimize what you have before you start digging in real deep.

 

Yeah going from a 302 to a 351 swap gives you more power but not much and also at the expense of less gas mileage. I would spend the money building up a 302 rather than swapping it out.

 

If the 351 is out of an 89 also you are looking at about a 25 hp increase and a 45 lb-ft increase. Not worth a swap out. And if the 351 is older, it would be even less of an increase. Spending that money on the 302 would be more beneficial.

 

Well no the 351c i here u can make em have near 500hp and hardly doin much to the motor the 302 only has 205hp @ 4,000rpm thats not alot.

 

True i mean it is my first truck after all but ill swap the motor in about a year or two.

 

500 hp in a daily driver truck? If you build up an engine for a truck, you should build it for torque, not horsepower. You will also need a different transmission, which also needs to be built. The only auto trans that will bolt to a 351C that's not electronic and can handle that kind of power is a C6, which is a 3 speed with no overdrive.

Getting 500 hp out of a 351c needs a lot more than "hardly doin much".

 

Why would the 351c get such bad mileage? My 71 mach I got 17-20 after I put in the overdrive. The 351c is a great motor and its not just a high end screamer. The main reason ford dropped it is the heads are huge making the engine to large to fit in smaller cars. They went with the smog controlled 351m 400m in trucks but the engine got dropped entirely before EFI came around that would have made it a great engine.

 

Tons of mustangs are getting built AOD's The C6 is far from the only option! Its very easy to get 400 hp out of a 4v Cleavland. 500 will take some cash..

 

I am going to ask since I don't think it has been brought up....but redneck, what is your goal with this truck? Are you wanting a daily driver that can get up and go a bit more, or a speed demon, or do you want it to pull? That will make it easier for us to suggest what to do.

 

The 351C had huge valves, intake and exhaust ports to support very high rpm. Denutted for emissions in my 73 Cougar, I averaged 10mpg. (with a 3 speed C6)