I have an awesome performance shop local to me that hosts dyno days several times a summer.

I made the dyno day in March where I made 233hp/286lbft with the following specs:
-2001 5.3 with 106K, now 109K’ish
-Completely stock internals
-Edelbrock dual intake
-Used/rebuild Speed Demon 750
-Ebay 3rd gen SS headers, 1 ¾” Primary, 3” collectors
-3” straight pipes to Thrust mufflers dumped at the axle
-Rebuilt TH350
-2000RPM converter
-Original 2.73 gears

Over the summer I added the following gems:
-TSP224R .581”/.581” 112LSA
-Comp Chromoly 7.400” pushrods
-Comp 918 springs
And at the July dyno day I made 310hp/300lbft!!.

The valvetrain upgrade transformed the Nova from a fun cruiser into a little terror and I am in LOVE!. The feel and the sound are almost exactly what I was hoping for and I feel little-to-no sacrifice to streetability.

For easy comparison:



Here is the vid of the July run:
*They tried to run the in 3rd gear on the first run. That dyno must have been at about 160MPH! haha. The second run was in 2nd and ran the engine up to 6500RPM.


Here is the link to the original “before cam” post https://ls1tech.com/forums/dynamomet...l#post18150982

Hope you find this all interesting and maybe even helpful!

 

Wow, must have had the crappest of crap LM7 cam in there

 

Haha, ya that might have been part of it. But I am sure that my fuel and ignition tune were not very good. Hence the early torque and HP peaks almost 1000RPM early.

I think there is still more on the table with the cam swap, but I am getting fed of chasing this carb tune. Over the winter I am stepping up to a truck based EFI system and HP tuners to help optimize the combo.

 

You are lucky it didn't blow the driveshaft out. If it were my car I would be having it inspected or replaced either way after that kind of stress (unless it is a 3.5-4" aluminum or chromoly). Look up "driveshaft critical speed".

Seems something was wrong with that motor on the before dyno. I just ran my truck for a baseline before a Cam Motion cam and with nothing but 2.5" dual exhaust (on stock manifolds) and some mild tuning it made 220/240 in a 2nd gear pull on a stingy dyno. That's through the truck rear end on 275/60r17s. Seems most stock 5.3s in trucks are in the 240-260 range on happier dynojets.

Your after results look very good though. Should make for an awesome driver and you might be able to squeeze a little more out of it.

 

Ya the before #s did seem low even for a stock cam. Another clue that something was wrong is how early the hp and tq curves peaked. HP peak was almost 1000RPM early. Adding a Innovate AFR gauge really helped me figure out my tune and make the most of both pre-and-post cam.

Another yes on the stingy dyno. The highest HP I saw that whole day was from a Pontiac BB stroker 468ci that made 335hp! There was a stock LS2 in a 6sp GTO that only managed 325hp and a Gen I 383 that made 325hp as well. I think they were all pissed when I opened the hood to show off a $275 junkyard engine that was only 15hp short of their engines! Love ma’ 5.3!

I think I do still have a little to gain from further fuel and ignition tuning, but the real hold-back is not the heads and 9.5CR. I am going to keep my eyes open for a set of 799 or 243 heads that I can shave .030” off and do a little port work on. Or maybe I will go the same route as Agearhead4life and drop some LS1 valves in my 862s, home port them and shave .030” off. We will see!

Thanks for the compliments and advice!

 

Yikes, sounds like yours is running very well right now then.

Awesome car too btw, don't see many people having fun with the 4 doors.

 

Good numbers.I put down 284rwhp and 295rwtq with bolt on 04 lm7 behind a t56

 

yea seems like a conservative dyno to me. Any idea what a/f ratio was or what timing was set at?

 

Thanks! I love rockin’ my more-door. And on July25th my wife and I welcomed our first child, Wyatt Griffin to our family, so in a few months those rear doors are going to start coming in handy!

Sic7, I saw your dyno thread and was very impressed with your #s, and a little disappointed in the 233hp I pumped out in stock form! Are you considering a new cam? I’d be very interested to see what a mid/mild cam would do for you.

My fuel tune is a work in progress. In my testing, I get low 13 to high 12 at WOT, but due to the 2,73 gears I can’t stay on the throttle long or I am over 100mph. Timing above 1600RPM is 32° with 13° vacuum, with the vacuum dropping out at 9PSIA, so WOT should be 32°. I am open to recommendations.

 

Not sure how the carb effects fuel and timing requirements but that sounds a bit lean and a bit much timing. Most na ls engines, from my experience like af between lambda 81-.85. Only a few I've done liked it leaner. One made more power at .90 but that is not common. Timing is usually best around 24-26 degrees but a few like 27-28 and again only a couple have taken 30 degrees. I've noticed the older cathedral stuff usually wants more timing. I cant recall a single NA rectangle headed engine liking anything but .82-.85 and 24-26*

Just my 2 cents

 

Really? That rich? ~11.8 -12.5? I have been aiming for high 12s. But it wouldn’t be hard for me to jet up and try it out for a few days. Thanks!

As I understand, carb’d engines like a little more timing the EFI as the fuel load is not as well atomized. That said, I double checked my curve and it is 28° base, and 17° vacuum. I based it on this thread, see Speedtiggers post #60. (He’s a pretty sharp cookie)

https://ls1tech.com/forums/carburete...ing-set-3.html

In the end this is all like polishing brass on the Titanic! I am tired of chasing my carb tune and will be going EFI over the winter. So I just want to get the carb tune to a happy place to get me through the rest of the summer, which is sadly fast approaching in the northwest!

 

If we a talking stoich 14.68, then 12.0-12.5. Before I began dyno tuning I use to target 12.7-13.0 thinking leaner is meaner but a majority of the time I don't see any gains going leaner than about 12.5...... I agree carbs are a pita lol

 

You say stock form, but in the first post you mentioned you made 233rwhp with the following mods which include headers and carb. So which one was it, did you make 233 bone stock of with bolt-ons cuz that makes a huge difference in what the cam gained you.

 

Redtan. I see how that statement is confusing. I should have calrified thate 233 was with all those bolts on parts, and stock INTERNALS.

The only changes made from the 233hp (before) dyno to the 310hp (after) was the cam, springs, pushrods, AFR gauge and a little time tuning.

 

Nice work. Sizeable gains from a small cam. That's always a win/win when it comes to a street cruiser.