hey i recently pulled the motor from my 73 maverick and im wondering what are some of the best ways to rebuild the original 302 ....trying to do away with some weight and hopefully add some horsepower...what would you guys recommend? and some sites you guys could give me... All help will be appreciated. Also what transmissions bolt up to the original 302 motor ...it had a 3 speed and trying to do away with it... Thanks for looking guys. Remember im going for street legal but hopefully badass Ryan
there are endless ways to do what you want. i personaly would build a 347 stroker. use aftermarket aluminum heads, a good dual plane intake like a perfromer rpm or wyand stealth. a 650-700 cfm carb. also i would probly get a newer 5.0 roller block that way you can use a roller cam. you should be able to build a 400 to 475 hp motor with that type of build. thats also an expensive build but you did not express concern about cost. if your concered about cost the stick with your short block. get some aluminum heads, a good cam. intake and carb. you can put a toploader, t5 trans, a c4, an aod, or several others. those are the popular conversions.
The C4 will bolt in with the fewest mods to your vehicle if you want an automatic. If you want more gears in a manual then the Toploader four speed is more than strong enough. The right version of T5 will go in but requires a lot of mods and the AOD is a non-choice unless you want to change the rear gearing to at least 3.7 or lower.
As long as running around with an overall gear ratio of 2.5:1 is acceptable. That could put his carb in the "off-idle" circuit and his engine at an rpm where it has very little power. With the low rpm any acceleration will put him in the "power" circuit of his carb (in the off-idle circuit) which is the richest combination possible. He might actually use more fuel than if he was using the C4. This is why I resist recommending the AOD without steeper gearing.
then again it...could not... what gear are you suggesting that would be ..."steeper"...than the 3:55s i suggested?
3.7 would give an overall gearing of 2.6 and a 4.0 would give an overall ratio of 2.8. I would suggest a minimum of 3.7x:1 but the preferred gear ratio would be higher than 4.11:1. 4.56 would provide an overall ratio of 3.2 which is close to ideal for a carbed engine at highway speeds.
Before you all get rapped up in rear gear ratios, better specifiy conditions for using an AOD. We don't normally run around in OD at less than about 45 mph so final ratio is not so important from that point of view. Out of OD it's back to 1 to 1 and some converter slip the same as a C4 or any top gear that is 1 to 1. There is a lot to be said for an AOD if built right and set up. There are later trans gears that give a low low first negating the use of any rear lower than about 3.73 in such a light car with a good amount of HP. Take a look at the Baumann trans website for the details. I run my Lincoln Mark 7 5L with an AOD, modded shift plate and a Kenny Bell Blower. In a 4400 lb + car, 3.73 is way more than enough on street tires. You know the OD ratio is about .66 which means 3.73 x .66 = 2.4678. Nothing wrong with that. The trans will down shift fine same as if you were using a 4 speed and pulling down a gear.
In 1:1 (3rd gear) the AOD is NOT the same as the C4. The AOD has a locking converter and that makes the engine respond to throttle pressure differently. Below 40 - 45 MPH it really doesn't make much difference because the lock-up is not supposed to happen until 45-50 BUT I have personally driven a factory AOD that locked up any time the speed was above 40 and I was using light throttle. This, in a 4200 pound car. It isn't a problem in a computer controlled, fuel injected engine because the programming is set up for lean conditions but in a carbureted car it can be a cause for poor gas mileage. The "problem" is more related to the fuel delivery than it is to engine or transmission.
all this transmission talk is good but has goten a little off topic. the op is looking for motor sugestions also. so lets give him some more.
No single component works alone. You are working with a complex machine that is made up of a lot of different components that all have to work together to work right (or at its best for your driving). When you add HP it comes at the cost of low end torque so you add gearing to make up for that. If you add an OD then you need to be aware of what kind of driving you will be doing and at what speeds. You may have to add more gearing to make the car more efficient at speeds above where the OD is working. There are a lot of variables and most have to do with the way you drive your car but if you are using a carburetor you should attempt to keep the RPM above the point where the idle and off-idle circuit is controlling the fuel to get the best mileage (which is the most often stated reason for using the AOD). That usually means running the engine between 1800 and 2000 RPM at freeway speeds as a minimum. If your cam doesn't allow the engine to produce much torque until you get to 2500 then that might be a better rpm to shoot for when choosing your rear gear. The engine is most efficient when it can produce about twice the power needed to maintain any given speed under the conditions that exist at that time. Where I live you don't go anywhere on level ground. It is always up or down a hill and if you go very far it is up and down mountains. The OD would be almost useless under these conditions unless I was running very steep rear gears (4.56+). If you live in Indianna where the only hill is the one you see on the horizon then you can get away with much less gearing. There is a lot to consider when you are making a change to the OD transmission and cost comes into play as well. The AOD is more expensive to build (2 -3 times) than the C4 and it is a swap that requires some extra gear to go with it. So consider all of that and the new gear requirements along with the advantages of both ways before you decide to just put in an AOD for better milage.
