Thread: Gen VI Daily driver build

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Hey guys, new to the site and was looking for some help on a Gen VI big-block build.

The motor in my 99 K2500 crew cab (Gen VI 454) developed an ugly knock, I found a good deal on replacement with only 20k on it.To the best of my knowledge, the new motor is a factor long block, with no additional work done to it. Before I swap the motors, I was thinking about making a few upgrades like cam and springs. I can find lots of info on massive hp builds, but not much in the way of daily driver builds. Any help would be greatly appreciated!

Any thoughts on cam and spring upgrades?
Plan on keeping fuel injection..is that a bad idea?
Will I need a new tune if I change cam and springs?
Any other thoughts would be greatly appreciated!
Thanks

I'm not worldly about hot rodding EFI and generally shy away from threads like this, but will give you some general direction.....
Generally speaking, the limiting factors on cam and lifters are:

1. Rear gears. Let's say that you have a set of 3.08 rear gears in your truck. The factory cam that was in the motor was engineered at the factory to work best with the 3.08 gears. As soon as you raise the operating range of the cam, you will also want to raise the numerical value of the rear gears. Depending on the lumpiness of the cam, you may want to go to 3.50, 3.73 or even 4.11, depending on the grind of the cam.

2. Static compression ratio. I have no idea what the stock static compression ratio of the motor was and you probably don't know either, but you should know that as you go wilder on the cam, the motor will want the static compression ratio to be raised also. Here is a table that I put together several years ago that will help you to understand. The 0.050" duration shown is only on the intake. The exhaust does not care, so it can be ground the same as the intake or the cam can be ground on a split duration where the exhaust exceeds the intake duration. Some fellows do that if they think the exhaust side of the motor needs a little help....This is the 0.050" intake valve cam timing that the motor will want for the static compression ratio shown......
8.0......185
8.25....189
8.5......194
8.75....200
9.0......204
9.25....208
9.5......212
9.75....216
10.0....221
10.25..227
10.50..233
10.75..236
11.0....240

As a further note, if you are looking for lumpy idle in a cam, you will want to be looking at 220 degrees intake duration or better, with at least a 10.0:1 static compression ratio per the chart shown. Be careful with fuel quality here, most cast iron headed motors will want to limit the static compression ratio to about 9.5:1, whereas aluminum headed motors can run pump gas up to maybe 10.5:1 or a little better, depending on fuel. Now, if a fellow intends to run the motor on E85, then there is no qualifier even with iron heads. Run whatever static compression ratio and whatever cam grind that you want to, you will likely not detonate the motor, even up to 15.0:1 static compression ratio.

3. Torque converter. From the factory, the torque converter was designed to give good fuel mileage and to move the vehicle from a standing start as efficiently as possible. It was also designed to stall at a minimum speed. When you change cams, you need to change the torque converter also. I know that many cam manufacturers will show you a list of cams and tell you that there is a cam somewhere in the middle of the chart that is the hottest cam you can use with the stock converter. Experience has shown me that as soon as you make a cam change, you need to make a converter change and a gear change too. And you need to completely re-do your centrifugal and vacuum advance. I hate having to jam my foot into the brake pedal to prevent the vehicle creeping at idle due to the higher idle which is used to make the cam happy. Get this firmly fixed in your mind.......THE CAM IS NOT A STAND-ALONE PART, IT IS DEPENDENT ON EVERY OTHER PART IN THE VEHICLE.

4. Lobe Separation Angle. Electronic fuel injection will want a taller LSA than a carbureted application. I would be looking at a minimum
LSA of 112, with an eye on 114.

Depending on the cam grind, modifications or replacement parts may be necessary to the EFI system and/or the computer. Like I said at the beginning of this post, I'm not worldy about hot rodding EFI.

Some of you fellows who don't want to jump through all the hoops to change a cam might do well with bolting on a 150 wet shot of N2O.
.

I don't traffic in the type of motor you have but will say that you would need top prob provide some more information. The cam is always the last part you want to choose unless you have a blueprint in front of you for a build. I'm sure you could make upgrades in other areas considering you're only interested in a daily driver, without looking to the cam for an answer. IE the cam compliments the parts you already have which is why 'it should always be the last part chosen.'

Have you looked at any of the RV cams? helpful in adding torque. And I'd say follow the cam mfg's directions. New Cam demands new lifters. Many will advise a roller type cam/lifter. I'd agree with them.

I'd definitely keep the EFI.

Originally Posted by techinspector1

I don't know anything about EFI and generally shy away from threads like this, but will give you some general direction.....
Generally speaking, the limiting factors on cam and lifters are:

1. Rear gears. Let's say that you have a set of 3.08 rear gears in your truck. The factory cam that was in the motor was engineered at the factory to work best with the 3.08 gears. As soon as you raise the operating range of the cam, you will also want to raise the numerical value of the rear gears. Depending on the lumpiness of the cam, you may want to go to 3.50, 3.73 or even 4.11, depending on the grind of the cam.

2. Static compression ratio. I have no idea what the stock static compression ratio of the motor was and you probably don't know either, but you should know that as you go wilder on the cam, the motor will want the static compression ratio to be raised also. Here is a table that I put together several years ago that will help you to understand. The 0.050" duration shown is only on the intake. The exhaust does not care, so it can be ground the same as the intake or the cam can be ground on a split duration where the exhaust exceeds the intake duration. Some fellows do that if they think the exhaust side of the motor needs a little help....This is the 0.050" intake valve cam timing that the motor will want for the static compression ratio shown......
8.0......185
8.25....189
8.5......194
8.75....200
9.0......204
9.25....208
9.5......212
9.75....216
10.0....221
10.25..227
10.50..233
10.75..236
11.0....240

As a further note, if you are looking for lumpy idle in a cam, you will want to be looking at 220 degrees intake duration or better, with at least a 10.0:1 static compression ratio per the chart shown. Be careful with fuel quality here, most cast iron headed motors will want to limit the static compression ratio to about 9.5:1, whereas aluminum headed motors can run pump gas up to maybe 10.5:1 or a little better, depending on fuel. Now, if a fellow intends to run the motor on E85, then there is no qualifier even with iron heads. Run whatever static compression ratio and whatever cam grind that you want to, you will likely not detonate the motor, even up to 15.0:1 static compression ratio.

3. Torque converter. From the factory, the torque converter was designed to give good fuel mileage and to move the vehicle from a standing start as efficiently as possible. It was also designed to stall at a minimum speed. When you change cams, you need to change the torque converter also. I know that many cam manufacturers will show you a list of cams and tell you that there is a cam somewhere in the middle of the chart that is the hottest cam you can use with the stock converter. Experience has shown me that as soon as you make a cam change, you need to make a converter change and a gear change too. And you need to completely re-do your centrifugal and vacuum advance. I hate having to jam my foot into the brake pedal to prevent the vehicle creeping at idle due to the higher idle which is used to make the cam happy. Get this firmly fixed in your mind.......THE CAM IS NOT A STAND-ALONE PART, IT IS DEPENDENT ON EVERY OTHER PART IN THE VEHICLE.

4. Lobe Separation Angle. Electronic fuel injection will want a taller LSA than a carbureted application. I would be looking at a minimum
LSA of 112, with an eye on 114.

Depending on the cam grind, modifications or replacement parts may be necessary to the EFI system and/or the computer. Like I said at the beginning of this post, I know nothing about EFI.

Some of you fellows who don't want to jump through all the hoops to change a cam might do well with bolting on a 150 wet shot of N2O.
.

First let me say thanks for the info!

From what I can tell from research, the motor has a 9.0:1 compression. Still checking on the gears.

Thanks again.