MSU BullDAWGz

First here is what I have & what it's used for. I have an '05 Suburban 1500 4x4 used mainly as dd. Will sometimes tow under 5k (1950 Super A) or a 2 horse trailer hauling cows.

Now my plan is to replace the cam and add LS6 blue springs, add a lower restriction intake tube to factory air box w/ k&n filter, port & polish tb, shorty headers, if possible an x over pipe or at least a cross over pipe added to cat back exhaust system along with a diablo tuner with custom tunes.

Will these mods work well in this combination? Here is cam specs.
Summit cam part # sum-8701R1
Stage 2 max w/stock torque converterRPM 2200-6500 but they say pulls to 7k
Duration @ 0.050 210° int 227° exh.
Valve lift (stock rockers) .522 int, .524 exh.
Lobe separation 112°

G Atsma

Shouldn't be any issues.

99 Black Bird T/A

iTrader: (4)

Seems like a good plan.

I'd prefer an excellent tuner do a custom dyno/street tune vs Diablo.

stockA4

Do you really need an engine in your truck that pulls to 7K?

The 8701 is a 218/227 112lsa. It's a copy of the old GM hot cam which when these engines were new was one of the only camshafts available. Even if you put this cam in a light Camaro you would be annoyed with the stock torque converter very quickly.

Yes you can make it work but you're going to give up a considerable amount of torque below 4K, so the truck is going to be slower and less responsive anywhere in the RPM range below that. You could put a stall converter in it but then it would be horrible for towing.

The 8701 is similar in specs to the BTR stage 3 truck cam 218/224 113lsa

Search YouTube, Richard holdner has lots of videos testing this kind of stuff, there's a test where they run a 5.3 with several camshafts including the one above that has similar specs yours. You'll see right away looking at the power curve that it's a bad idea. Sure if you floor it and keep the revs up it's faster than it was when it's stock but your transmission in a heavy truck has absolutely no interest in shifting past 6k so you'd be much better off looking for a cam that peeks below that.

I have an '04 suburban with this cam in it, however rebuilt the 5.3L with flat top pistons so my compression is closer to 10.5 than the stock 9.5, my truck also has 4.10 gears to help it get moving. My tune is also spot on. My engine would easily pull to 7K, It's completely overkill for a big truck.

The low end loss with my setup maybe less than yours due to my added compression however I drove the truck with the stock engine for a long time and I can tell you that the stock engine with the stock cam is better everywhere below 4K in a heavy truck like this.

I have another cam on the shelf that I'm going install from a previous project and it's going to run a lot better

It's a 204/222 112 LSA SDPC camshaft

You can search this one on YouTube as well and you'll see from the power curve that the gains come a lot earlier 2,500 RPM or so, look for a stage one cam or If you want a rough idle I've heard good things about the truck Norris camshaft, something like this Imo

grubinski

this.

99 Black Bird T/A

iTrader: (4)

Wow that will teach me to look at the forum before finishing the first cup of coffee ☕️, I didn't catch the typo. What they said ^^^^ that cam is suboptimal for towing etc.

Maybe that popular 212/218 truck cam would be one to consider?

MSU BullDAWGz

According to Diablo the tuner I was looking at can store multiple tunes, and they have custom tuners across the country. Reason for multi tunes is I wanted 2-3 tunes, 1 for regular gas and a more aggressive tune for 91+ octane. Possibly even a 3rd for towing. I would only do the Diablo IF and only IF they can do custom tunes as in cat delete, cam n intake, fuel trim as well as generic things like rpm limit, shift points, gear change, tire size etc...

MSU BullDAWGz

First I want to thank all that responded. The info on the cam was a huge help as I was thinking it was aggressive stage 2 cam but the way Summit worded it I thought that cam would make more torque down low. But hearing from actuall users is better than an add.

So... Here is a new list of cams (2cams will need better springs but all other mods will be same)

Sum-8719R1 ( high lift )
Duration @ .050 209°int 217°exh
LSA 212°+1
Lift .550 int & exh
RPM 1800-6200
Advertised duration 261int 270exh
note: will need better springs than factory LS6

Sum-8728R1
Duration @ .050 212°int 218°exh
LSA 110°+3
Lift .600int .585 exh
RPM 2k-6500
Advertised duration 261/267
note: will need better springs than factory LS6's

_
Sum-8712R1
Duration @ .050 210°int 218°exh
LSA 112°+1
Lift .500 int & exh
RPM 2k-6k

Sum-8718R1
Duration @ .050 205°int 217°exh
LSA 112°+2
Lift .500 int & exh
RPM 750-6k

I'm leaning towards the last 2 as correct me if I'm wrong. @ .550-0.600 inch lift isn't there an issue with valve retainer to valve guide clearance problems AND/OR valve to piston?!?! I know on gen I&II it would.

Che70velle

iTrader: (6)

Your best bet for torque in this application, where your towing a lot of weight (comparatively speaking for a gas burner) is rear gears and a supercharger. Here’s why…the camshaft change might get you a 30 ft. Lb increase…maybe a few more…but it’s going to give you an increase at a higher RPM range. This means your revving the truck higher to move it faster. It will feel stronger at 4000 rpm, but will actually be weaker at lower RPM’s, which is what your trying to help. You will NEVER make more torque at low rpm’s with a bigger camshaft than stock, with the same cubic inches. Your friend for towing weight is cubic inches, but that’s a different sermon. Rear gear change will help towing exponentially. You won’t believe the difference gears will make for towing. A supercharger will artificially increase cubic inches by making the engine feel bigger than it actually is. The supercharger will make a ton of torque right off of idle, and make you feel like you just put a big block under the hood, and it will do this with good fuel economy when not making boost, ie normal driving conditions when not towing. You could pick up 100 hp and 80 ft lbs with the right camshaft, exhaust, intake, converter, etc, but it wouldn’t pull an empty trailer, much less one with weight on it, and it would have to go to 6k rpm to do so.
I built a 6 liter a few years ago for my brothers truck. He pulls a trailer a lot. Went .030 over, 10.5:1 compression, good heads, h-beam rods, 2500 stall converter with a big cooler setup on the trans, and a little 219/231 camshaft. It makes great torque but could still use a gear change to make it “perfect’’.

99 Black Bird T/A

iTrader: (4)

Here's my understanding, experienceand observations, hopefully others will add more exacting detail etc.

Lift is less of an issue with Gen 3/4 engines compared to the Gen 1/2 SBC's generally speaking. Lift shouldn't be an issue for any of the cams listed above for retainer to valve guide clearance problems AND/OR valve to piston if it's properly installed.

Duration can be a P to V issue in mid to high 230's with stock pistons without fly cutting or even 230 duration if the valve job was sunk by the head porter with stock pistons or flat tops in some cases. My experiences, under 230 haven't seen P to V issue. Can't speak for others etc.

It's always best to check P to V etc and confirm in case the heads are jacked up with valve at different heights or the heads or block was decked excessively etc. You know the drill...

Lift over ~ .551 will cause the stock 1.7 rocker to scrub the valve tip since it isn't a roller rocker tip. In my experience this is ZERO issue for ~.581 lift cams as I've ran a .581 lift XER lobe cam for 130,000+ miles without issues. However as lift goes up the scrub gets more pronounced and can cause premature valve guide wear and or valve tip wear. Most folks feel ~.600 lift is very acceptable. I say that because lots of folks run those lifts etc. Many draw the line at cam lifts over ~.625 to .630 if longevity is a majority issue. Some have ran .650 lift with stock rockers etc. Risk reward and all that.

Personally, over .625 I'd want a roller rocker. Under .625 I'm good with stock rockers.

MSU BullDAWGz

To Che70velle,
thanks and your mostly correct. If built right and matched correctly you can make more torque down low and have more to hp up top over stock and still get better mpg too. The reason I say this is Chevy had to build these vehicles to all 50 states laws and what the majority of customers want. I live in a state where I can cut the cats out as there is no exhaust checks. I don't care if my true cold air makes noise. Adding an x over or cross over pipe adds both lower torque and top end hp. Also if the torque remains the same and I increased hp at 4k-up then mpg will go up as you wouldn't need as much throttle to increase or remain at that rpm. My mods and correct cam choice should add bottom end and some to the top. Granted not like an to air pump would do. But I want simple mods I can do and not spend $10,000+. I'd be better off selling my truck and buying one someone else spent tens of thousands on and can't get half of it back selling the truck. Also I'd rather a turbo than a blown 5.3. As a matter of fact I'm slowly working on a turbo'ed 5.3 to go in an 85 K20 which has a max'ed out 383ci 400 th w/ np208 transfer case, 4.88 gears, detroit locker in the 14 bolt and limited slip in the 10 bolt up front. She also has 38" STL Super Swampers. So yea I know about gearing and top vs low end power. I just don't want to replace torque converter in a dd. They add heat n wear to tranny. I refuse to change gears front and rear too as that kills mpg. I'll only tow on rare occasions as I only got 3 cows & a bull and only haul the calf's to do slaughterhouse when around 18 months old (average 1 every 6 months) or buying a replacement. Or towing a 3800 lb Super A to be fixed IF I can't repair it myself. (ie splitting it) so your mostly correct but turbo'ed is better as it's free hp but I want simple, long life, easy to work on. Basically stock with a few mods perfectly matched.

Please don't think I'm trying to bash on you, except for the 4000 rpm thing you are 100% right and ppl have argued over turbo vs blown since before WWII. I just like turbos. I luv GM new and some old but I also loved my ROUSH mustang (now that had a blower lol) and I've had 70Cuda & 71 Road Runner both with 440's in em. So I appreciate your help, in just doing this as a small thing. My mudbog/river rat and rat rod is where I want max'ed out power adders like twin turbos or a huge blower.

CattleAc

iTrader: (7)

I know this is a "car" site, but I need pictures of said Super A...

Che70velle

iTrader: (6)

The A might have an LS. Heck…it’s been swapped into everything else, why not? 😜

grinder11

iTrader: (1)

Couldn't have said it better myself. There's a great read out there online somewhere written by Ken Dutweiler (2 t's? Man, my memory!!) that talks about FI boost. Dutweiler knows his stuff. He also goes into questioning cubic inch displacement as it relates to rpm. His theory on that is basically that if you have, say, an older Gen 1 305 SBC, that makes 200hp@3,700rpm, if you double the max power rpm to 7,400, with the aftermarket equipment needed to make max power at that high of rpm, he believes you've effectively made the engine a 610 cubic inch engine!! I may have a few figures wrong, because it's been awhile. But if your boost level is 50% over atmospheric, it's basically like taking a 5.3 liter/325 cubic inch engine, and turning it into a 50% larger engine, which would now be a 487 cubic inch engine. IIRC, atmospheric is 14.7(?). So adding 7.35lbs boost (not considered much at all), will give you your 487. For a truck, I'd go with a positive displacement blower, like a Maggie, or similar. I know it's somewhat more $$ up front, but in the long run, I think it'll be more reliable, get better mileage, and have more low end torque than any N/A setup, all of which are a win-win-win in a towing rig, or just a big truck when not towing anything. Hope this helps.....

2Heavy4Fast

Let me start by saying, Hail State! Now, regardless which direction you ultimately decide going with your build (for what it's worth, @Che70velle is spot on with what he suggested) but you're going to need a custom tune, and I know through experience that although that are no shortage of people that tune LS engines in Mississippi, there aren't a lot of actual, legit "tuners" around. Not sure where you're located, but if you're reasonably local to the Jackson area, there's a shop in Byram, MS called KAR Performance, and more specifically, one of the owners of the shop named, Kenneth Myers. EXTREMELY knowledgeable and experienced when it comes to everything from basic cam installs all the way to the "you dream it" type of custom engine builds, and easily one of, if not the most, experienced tuners in the state. From my personal experience, it seems as though most of their work focuses on the LS and LT platforms. He has always made time for me and my questions, always had the right answers to those questions. I really highly recommend him. Also one of the few places around with a dyno!

Also, you should consider a BTR Truck Norris cam is you're looking for something that plays well with a stock converter. When it comes to towing load with it, you'll probably find yourself needing to physically shift the the gears on the column, but in regards to just being a DD, other than having to bump your idle up about 250rpms to keep good vacuum, it will drive exactly as it does stock on the stock converter. BTR also just released a version called the Truck Norris NSR which is the same camshaft, just with the lobes worked down enough so that you can use it with the stock springs. So, for wanting a bit of a performance increase without adding FI, while keeping the stock converter, and keeping some beer money in your pocket, that's the cam I would go with.