Camshaft advise, please
#1
Camshaft advise, please
Hello all! I have a Factory Five Cobra replica with which I committed blasphemy by installing an LS Specifically the LS376/525 (https://www.chevrolet.com/performanc...s/ls/ls376-525). This car is more show than go (although, at 2300lbs it has plenty of go). As it is more for show, I would like to get more lope in the idle but I don't speak fluent camshaft. I'm not specifically looking for more power, though more is always better, and am not terribly concerned with drivability issues as long as they aren't extreme. The cam that came in it is the 88958770 with these specs:
Thanks so much for any insight you may be able to provide!
Glenn
- Duration @ .050" Lift( Deg): Intake: 226 / Exhaust: 236
- Maximum Lift (in) W/ 1.7 Rocker: Intake: .525 / Exhaust: .525
- Lobe Centerline ( deg): 110
- Technical Notes: Cam requires valve spring P/N 12499224 (which I can only assume is what's in the motor since GM assembled it)
- Duration @ .050" Lift( Deg): Intake: 233 / Exhaust: 276
- Maximum Lift (in) W/ 1.7 Rocker: Intake: .595 / Exhaust: .595
- Lobe Centerline ( deg): 107
- Will this cam do what I want? The lower LSA and more duration means more lope, correct?
- Will the extra lift cause valve interference issues?
- Will it work with the existing valve springs and/or any other components that I would need to replace?
- What overall effects on power output and drivability should I expect?
- Is anyone thinking "Holy crap, don't do that! Get cam XYZ instead!" ?
Thanks so much for any insight you may be able to provide!
Glenn
#2
TECH Junkie
iTrader: (28)
Most of the GM camshafts are older profiles that have been around forever. BTR (Brian Tooley Racing) has a Spintron machine that makes sure valvetrain harmonics are in check and makes great power plus they constantly are in development and have updated versions of their cams. A Stage1 or 2 LS3 cam should be all that you need and it will still drive great. https://briantooleyracing.com/btr-ls...-camshaft.html
You would need dual springs. Also the LS3 motors have a crappy design on the cam chain guide (they fail) so you should swap over to an IWIS chain and LS2 style guide when doing a cam swap. You can also get the intake manifold ported and "rod modded" to smooth out airflow which can be worth 15-20rwhp depending upon how efficient the rest of the engine is (long tube headers?).
A tuner could also simply tune it for more "lope" at idle with what you have.
You would need dual springs. Also the LS3 motors have a crappy design on the cam chain guide (they fail) so you should swap over to an IWIS chain and LS2 style guide when doing a cam swap. You can also get the intake manifold ported and "rod modded" to smooth out airflow which can be worth 15-20rwhp depending upon how efficient the rest of the engine is (long tube headers?).
A tuner could also simply tune it for more "lope" at idle with what you have.
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wannafbody (04-28-2024)
#3
12 Second Club
In general, yes, a tighter LSA will create a more lopey sound via overlap. TSP has some pretty rowdy sounding cams, but you will need stiffer springs for those. The Titan-3 (Cammotion) sounds good. Again, need stiffer springs. I absolutely would not use a GM cam. For the price of the cam you are looking at, you could buy 2 Summit cams. The aftermarket cams will also perform better. Unless someone gives you a GM cam, I wouldn't recommend using it.
I couldn't find the specs for your valve springs, but I would assume they are limited to .550 lift like most factory performance springs. You could probably use a .550 lift truck cam with your springs, but that's about it. Most performance cams are going to need at least .600 lift springs. Summit sells a nice .600 lift dual spring kit, if you go that route.
I couldn't find the specs for your valve springs, but I would assume they are limited to .550 lift like most factory performance springs. You could probably use a .550 lift truck cam with your springs, but that's about it. Most performance cams are going to need at least .600 lift springs. Summit sells a nice .600 lift dual spring kit, if you go that route.
#4
TECH Enthusiast
That GM stage 3 cam will probably drive like a bag of dicks, I would steer clear of that if I were you.
Since you want more lope, I suggest a GPI SS3 cam. They sell a lot of these, so a good tuner should still be able to extract pretty decent driving manners out of it.
While a BTR stage 1 or 2 LS3 cam would perform great, I don't think it's going to give you the lope you want. The cam you currently have will lope more than the stage 1, and maybe even more than their stage 2 (AKA Red Hot cam). Neither of them have much overlap.
Since you want more lope, I suggest a GPI SS3 cam. They sell a lot of these, so a good tuner should still be able to extract pretty decent driving manners out of it.
While a BTR stage 1 or 2 LS3 cam would perform great, I don't think it's going to give you the lope you want. The cam you currently have will lope more than the stage 1, and maybe even more than their stage 2 (AKA Red Hot cam). Neither of them have much overlap.
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DualQuadDave (04-29-2024)
#5
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#8
TECH Enthusiast
i really like the gpi ss3 cam profle, have a buddy with one and he loves it. sounds fantastic and drives pretty good ( tuner is really good) . as others have said those GM cams are out dated tech. almost any cam (cammotion,tsp,gpi,btr,summit racing) is gong to make more power and just overall be a better choice no matter witch one you go with.
#9
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OP,
You've received some great advice from the community. If all you're looking for is a lopier idle you can have a tuner put a "lope" tune in it as @spanks13 suggested. Also, something to note is lope is subjective. Meaning what one person deems lopey another may say it's not.
If you wanted to change out the cam our SUM-8711R1 would fit the bill here. It's the largest Pro LS cam that will work without flycutting for a stock bottom end LS3 with un-milled heads. Specs on it are .625/.605, 234/248, 114+3.5 with 14* of overlap. We feel it has a strong lope with its 7* BTDC intake valve opening. The intake valve opening is basically where the idle quality comes from. The earlier we open the intake valve the "lopier" the idle will be at the expense of idle vacuum. As a comparison, your current cam opens the intake valve 3* BTDC.
You'll need a .630" lift beehive or .660" lift dual spring for the 8711R1. You'll also need some different pushrods. We typically see a 7.425" pushrod work for the 8711R1. However, things vary so we always recommend measuring for pushrod length before purchasing pushrods. We offer the TFS-9501 pushrod length checker to measure pushrod length.
Here's an example idle video of the 8711R1
You've received some great advice from the community. If all you're looking for is a lopier idle you can have a tuner put a "lope" tune in it as @spanks13 suggested. Also, something to note is lope is subjective. Meaning what one person deems lopey another may say it's not.
If you wanted to change out the cam our SUM-8711R1 would fit the bill here. It's the largest Pro LS cam that will work without flycutting for a stock bottom end LS3 with un-milled heads. Specs on it are .625/.605, 234/248, 114+3.5 with 14* of overlap. We feel it has a strong lope with its 7* BTDC intake valve opening. The intake valve opening is basically where the idle quality comes from. The earlier we open the intake valve the "lopier" the idle will be at the expense of idle vacuum. As a comparison, your current cam opens the intake valve 3* BTDC.
You'll need a .630" lift beehive or .660" lift dual spring for the 8711R1. You'll also need some different pushrods. We typically see a 7.425" pushrod work for the 8711R1. However, things vary so we always recommend measuring for pushrod length before purchasing pushrods. We offer the TFS-9501 pushrod length checker to measure pushrod length.
Here's an example idle video of the 8711R1