preformance

hi guys just want to know what is the best wat to improve preformance on my 73 mack 1 it dosen't need to be a rocket but a little extra power would be nice any ideas?

Howdy!

Mostly it depends on what you are starting with and what your plans are. How much gas milage are you willing to give up and what kind of driving you do.

It would be helpful to know the engine/transmission and rear end ratio. If the engine has any performance modifications that would be good to know. Also, if you know how many miles are on each.

Generally, if you want a quick performance increase you should swap out the rear end gears for a 'higher' ratio. So if you have a 2.73 then a 3.00 or 3.25 woudl be a 'higher' gear ratio. This is pretty inexpensive and effective for most any car. This will help the car get going quicker but will reduce your overall top speed and will decrease your gas milage too.

If you want both quicker and faster you will need to look at engine upgrades or transmission swaps. Engine upgrade costs will vary widely. A tranmission swap is never inexpensive.

Most engines do better with an upgraded ignition system. (If you have points now). You also can get more performance by swapping a 4bbl carb on in place of a 2bbl. This isn't too expensive. After that I would look at dual exhausts (not too expensive) and headers. That's pretty much it for external bolt on.

1. Make sure it is currently running properly. You would be surprised how much performance you would lose from a single spark plug not firing.

We will probably make a check list in the near future(you can refer to the 335 forum, http://www.network54.com/Forum/119419 because I think everyone here agrees there is a lot of great 351c info there), but things to check are:

1. Cylinder compression.

2. Vacuum Pressure at the manifold.

3. What are the exact components in your car: displacement, carb, intake, cam, pistons, torque converter, rear end gear, exhaust type. The reasons for this are below.

2. I personally don't believe there is a cheap way for the following reason: the best running engine is a well balanced engine. Changing one component typically requires at least an adjustment if not replacement of others. Otherwise your engine is fighting itself, and may be faster but not actually running well. Some guys will take faster over running well. I am not one of them.

A recent issue which came up when someone mentioned a 351C 2v torque convert is rated at 1500 RPM(or so), while a 351C 4V was rated at 2700 RPM. Overlooking this would DRASTICALLY limit your 351C 4V.

3. If you have a well running 351c 4V motor, it should scream. If screaming is not fast enough for you, then you will in all likelihood need to take several steps to increase power.

But first, see step 1.

Good luck.

Howdy!

Mostly it depends on what you are starting with and what your plans are. How much gas milage are you willing to give up and what kind of driving you do.

It would be helpful to know the engine/transmission and rear end ratio. If the engine has any performance modifications that would be good to know. Also, if you know how many miles are on each.

Generally, if you want a quick performance increase you should swap out the rear end gears for a 'higher' ratio. So if you have a 2.73 then a 3.00 or 3.25 woudl be a 'higher' gear ratio. This is pretty inexpensive and effective for most any car. This will help the car get going quicker but will reduce your overall top speed and will decrease your gas milage too.

If you want both quicker and faster you will need to look at engine upgrades or transmission swaps. Engine upgrade costs will vary widely. A tranmission swap is never inexpensive.

Most engines do better with an upgraded ignition system. (If you have points now). You also can get more performance by swapping a 4bbl carb on in place of a 2bbl. This isn't too expensive. After that I would look at dual exhausts (not too expensive) and headers. That's pretty much it for external bolt on.

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as far as i know the engine is all original no modifacations not sure what the rear end ratio is but the car is auto 351 2v

+1 on will e's post. I see on your profile page you have a 351C. IMHO Whether it be the 2V or 4V, an aluminum intake and carb along with headers will put a smile on your face. If you don't want to go that far, first try getting a hotter set up on your ignition system and procede from there. You'll find lots of advice from the group on the ignition set.

Hey, Danny. I believe we have the same engines. Mine is a 351 2V. After rebuilding it with a snappy cam, performance intake, Holley 600cfm carb, Hooker headers, etc. it gets up and goes if I can find some water or gravel to take off from, so that the RPMs get up to 4000 faster. Otherwise, there's not much to get the adrenaline going. We probably have the same tranny as well. Mine's an FMX, and with tall gears (2.75:1), so it's hard to get the engine to wind up fast enough to chirp the tires, let alone do a burn out.

I would look at the bolt-ons described above and think about swapping rear ends to a 3.25 or 3.50. With EPA regs of 1973, power and performance were tossed out the window in favor of gas mileage, which resulted in our killer Clevalands acting like lukewarm family sedans.

I always tell people the heads are the key to making power. Since the Cleveland heads are pretty good to start with, I woukd say the best bang for you buck would be a set of gears. With the automatic, a "lower" gear ratio (3.25 or 3.5:1) would be most practical. Of course that depends on your intended use. I woukd go with 3.25:1 since I drive on the freeway most of the time.

After gears, I would consider a full exhaust. Mid-length headers, 3 1/2" pipe and a flow through muffler (my preference).

After that, I woukd go with a performance dual plane intake manifold and a 4bbl carb. I like Deamon and Holley. 600-650cfm is all most people really need for a street 351.

If you want to go any farther you can always have your heads rebuild (cleaned up on the inside) and a healthy cam. I like a hydraulic roller 224/230 @ .050