Choosing Cam
Thread Starter
Staging Lane
Joined: May 2024
Posts: 62
Likes: 7
Choosing Cam Hello I am in the process of building a gen 3 5.3. I have completed installing the main bearings,rod bearings and rings. Now I am trying to decide which cam to go with. The heads I am using are the 706s.I have been looking to a ebay cam called the sloppy mechanic cam stage 2. What are the pros and cons of running a big cam. I know the kit comes with different springs and seals. I planned on having AC/Power brakes
Launching!
Joined: Jul 2014
Posts: 295
Likes: 102
From: Duluth, Minnesota
Hello I am in the process of building a gen 3 5.3. I have completed installing the main bearings,rod bearings and rings. Now I am trying to decide which cam to go with. The heads I am using are the 706s.I have been looking to a ebay cam called the sloppy mechanic cam stage 2. What are the pros and cons of running a big cam. I know the kit comes with different springs and seals. I planned on having AC/Power brakes
I am procharged and have a Bald Eagle Boost Cam and am planning on switching to that cam but boost version.
Cons you gotta upgrade the valvetrain and top end with it.
When I did my cam I upgraded all the way through my injectors.
If you get the right cam it can really open the motor up and put down power. My setup the current cam did not do that for me.
Thread Starter
Staging Lane
Joined: May 2024
Posts: 62
Likes: 7
NA right now. I gapped the top and middle ring .022 -.026.
The sloppy mechanic cam I looking at comes with the springs,cam, and valve seals. The ad didnt mention if the rocker arms or push rods needed to be replaced.
The sloppy mechanic cam I looking at comes with the springs,cam, and valve seals. The ad didnt mention if the rocker arms or push rods needed to be replaced.
TECH Regular
Joined: May 2023
Posts: 417
Likes: 138
From: Franconia, PA
^^^^This. Also the Summit 8720 outperformed the sloppy stage 2 in richard holdener's dyno tests in a 4.8L. Depending on the vehicle (car, truck, goals, etc) I would recommend that instead.
8720 specs: 218/227, .600, .600, 112+2
8720 specs: 218/227, .600, .600, 112+2
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Verdad Gallardo
Joined: Apr 2006
Posts: 3,890
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From: Grand Rapids, Michigan
If it has 2.xx gears in it, you really need to change them out. My old '85 Monte Carlo had 2.29 gears from the factory and it was an absolute pig on the street. Just going to a 3.42 from a 2.29 dropped over 1 second 0-60. Adding a cam that will kill a bit of low end torque will make it even slower off the line.
LS1Tech Sponsor
Joined: Jan 2008
Posts: 2,233
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From: Ohio, Georgia, Nevada, Texas
OP,
We could see going with the SUM-8720R1 that @Abs suggested. Specs on it are .600/.600, 218/227, 112+2 with -1* of overlap. You can expect a smooth to noticeable idle depending on the idle speed. This will be great in the mid-range with a good top-end. Pair it with our .600" lift beehives and it'll be happy out to 6,500+. It's the largest we recommend with a stock torque converter.
The SUM-8728R1 might be another one to look at. Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. If this has some 2.XX gears this is the one we'd look at. It shifts the powerband to the left for better low-end and mid-range power/tq. The intake valve closing (IVC) is basically what sets the powerband. The earlier we close the intake valve ABDC the earlier the powerband typically starts and ends. The 8728R1 has a 33* IVC @.050" VS. 39* for the 8720R1. The 8728R1 has a steady lope and will make great torque from 2,000 on up. It'll pull well to 6,500+ with the above .600" lift beehives.
Here's a good video of different ways to identify what gear ratio you have.
We could see going with the SUM-8720R1 that @Abs suggested. Specs on it are .600/.600, 218/227, 112+2 with -1* of overlap. You can expect a smooth to noticeable idle depending on the idle speed. This will be great in the mid-range with a good top-end. Pair it with our .600" lift beehives and it'll be happy out to 6,500+. It's the largest we recommend with a stock torque converter.
The SUM-8728R1 might be another one to look at. Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. If this has some 2.XX gears this is the one we'd look at. It shifts the powerband to the left for better low-end and mid-range power/tq. The intake valve closing (IVC) is basically what sets the powerband. The earlier we close the intake valve ABDC the earlier the powerband typically starts and ends. The 8728R1 has a 33* IVC @.050" VS. 39* for the 8720R1. The 8728R1 has a steady lope and will make great torque from 2,000 on up. It'll pull well to 6,500+ with the above .600" lift beehives.
Here's a good video of different ways to identify what gear ratio you have.
TECH Resident
Joined: Jun 2011
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Difference between a genuine SS2 (Elgin 1840P) and the Summit should be <$70. If it's cheaper then it's a fake; questionable in quality, likely not even actually ground to the state specs, and it plus any components that come with it could damage your engine long term. eBay is rampant with these fakes and Amazon not much better.
Whether real or not, choosing a cam that isn't the best fit for your setup will be disappointing in the end. With all the money and effort spent do it once, do it right.
Whether real or not, choosing a cam that isn't the best fit for your setup will be disappointing in the end. With all the money and effort spent do it once, do it right.
Last edited by 68Formula; Jun 22, 2024 at 04:43 PM.
Thread Starter
Staging Lane
Joined: May 2024
Posts: 62
Likes: 7
Would it be smarter for me to get car running with a stock cam? Im planning on using stand alone harness and maybe a ECM from a tahoe/silverado and get everything wired up would the engine run with the modified cam or would I need to get the computer tuned before the engine runs?
Last edited by LSpann; Jun 24, 2024 at 06:52 PM.
Joined: Apr 2006
Posts: 3,890
Likes: 1,137
From: Grand Rapids, Michigan
If it were me, I'd put the cam in first and send the ECM off to a mail order tuner. With the amount of work it takes to swap a cam in the car, it doesn't make sense to wait. A mail order tune is going to run you like $300 at most. You're not building something that is uncommon, engine-wise, so any mail order tuner should be able to get pretty close with the tune.
Thread Starter
Staging Lane
Joined: May 2024
Posts: 62
Likes: 7
I was planning on running fuel injection with my current build but I see in order for my 700r4 to work I would need a car carb due to the pressure cable the 700r4 has. Most of the standalone harnesses I see require the 4l60e and up so I will be swapping the trans to the 4l60 or better. As for gears I was aiming for 3.73s. Would the summit 8270 still be a good choice?? I was wanting to change the stall too but not sure how high I should go.
