Topic: Best Bolt On's for performance?

[Main One]

Your 5.3L is based on the LS1 design.  The LS1 has about 25 more cubic inches and an aluminum block - just about all of the other differences are very minor.  The LS1, LS6, 4.8L and 5.3L without cylinder deactivation are considered the Chevy 3rd generation small block, or Gen III.  Parts are generally interchangeable in these engines, although of course there are cylinder diameter and stroke differences to accommodate the different displacements.  The LS6 was the souped up version with the hottest cam and some fairly exotic valves.

So what are your thoughts/concerns about putting a 2004 Z06 (LS6) cam in my AV?  Thanks! 

I believe a Z06 cam with better pushrods and springs would perform very well, assuming you didn't push the rpms above what the stock lifters can take without starting to tick, which in my truck is about 6200 rpm.  It isn't as aggressive as some you have been looking at, and you probably don't HAVE to get a custom tune since it doesn't lope at idle.

You could do titanium retainers with it, but if you stay below 6200 rpm I don't think you'll need them.  I'm using the stock retainers with a cam that is supposed to float above 6600, shifting at 6100.

[Ski Edition]

I can't remember me driving my truck at over 4500 RPMs ever. Even towing!!

[Main One]

I can't remember me driving my truck at over 4500 RPMs ever. Even towing!!

OK.  I've got to ask the question, Why do you say you need more top end power, when you've never been there?

[MyBigToy]

OK.  I've got to ask the question, Why do you say you need more top end power, when you've never been there?

I was kinda thinking the same thing........IIRC, maximum throttle stock shift points are 5200 rpm.

[Ski Edition]

Good point!!  Maybe mid-range is what I'm referring to in your terms. 55-100+ is where I need help. Maybe I'm not utilizing what I have and not being hard enough on her!!??

[Main One]

Good point!!  Maybe mid-range is what I'm referring to in your terms. 55-100+ is where I need help. Maybe I'm not utilizing what I have and not being hard enough on her!!??

You may not be pushing her hard enough to stay in the engine's power range.

From the above post and others, it seems you are looking for more power around 55-70 mph?  Is this correct?

With your gears and tires, what rpms is your engine turning when you are on the throttle in this speed range and wanting more power?

[Ski Edition]

Correct and I'm in the 3200-3300 range and she is slow to pick up speed.

[Main One]

Correct and I'm in the 3200-3300 range and she is slow to pick up speed.

With your tires and gearing, do you know how many rpms you are turning at say 55 or 70 mph under light throttle, or conversely, how fast you are going at say 2000 rpm in 4th gear at light throttle?

[Ski Edition]

I know I run 72-73 @ 2500. When I kick it from there that is where I'm really disappointed.

[Main One]

I don't know, but suspect, that you aren't going to find a cam that gives you much more power over the stock one at 3300 rpm and below.

I'm thinking that your problem is gearing related.  If you're turning 2500 rpm in 4th with the converter locked up, the 4l60e gearing is so wide that unless you want to be turning around 6500 rpm, you are only going to get a downshift to 3rd.  With tuning, you could change your WOT shift points such that at say under 70 or so, you could hit 2nd, but by about 75 it would be shifting back into 3rd at 6000 or so rpm.

I'd say your best options, if this range is where you want more power, is to either go to say 3.73 gears, an overdrive unit that would give you basically an 8 speed transmission, or a looser torque converter such as MBT is running.

As a for instance, in my truck, I'm turning 2000 rpm at 70, so at 2500, I'd be turning running about 88 mph.  With my gearing and where I'm shifting into 3rd, I'm holding second gear until about 89 mph.  I've got decent power in the range from 60 to nearly 90, then drop off some when hitting 3rd gear.  I've got a bit of a low spot power wise, like you are describing, around 45-55, but it doesn't take as much power to accelerate through those lower speeds as it does around 60-70.

Gear Vendors overdrive units are very popular with RVs and trucks doing a lot of towing.  As I noted previously, they are not cheap and hard to find used for late model transmissions.  Additionally, you would have to add the cost of a shortened rear driveshaft and lengthened front driveshaft, since they sit at the output end of the transmission and would push the transfer case farther back.

One other option would be to install a 4L80e transmission.  These have much narrower gear ratio changes between gears.

Looking at the 4L60 and 4L80 gear ratios on the Gear Vendors web site, if you were turning 2500 rpm in 4th with the torque converter locked, and downshifted into 2nd, you'd be pushing 5900 rpm, with the 4L60e.  With a 4L80e and your current gearing/tires, at the speed you are now turning 2500 in 4th, you would now be turning 2680 in 4th, and if from there your 4L80 downshifted into 2nd, it would be turning under 5300 rpm.  This is without an external overdrive unit.