6.1 cam swap. Big deal?

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Buschi340

Buschi340

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looking for a cam with a little bit more "punch" without loosing idle too much. For time to time drag racing. This is a carbed engine. 5 speep Toyota Supra shifter.
Did you guys swapped your stock cam? Why and results?
And is it a big deal? Heads have to go off, right?
 
The good news is the heads don't have to come off for a cam swap in the new 3G Hemis. There are keeper sleeves that hold them up and out of the way so you can pull the cam without pulling the lifters. Pull the rockers, pushrods, and timing cover and when you spin the cam around it will push them up into the keepers so you can pull the cam out. Just did this on my 5.7 not that long ago.
 
Map63Vette said:
The good news is the heads don't have to come off for a cam swap in the new 3G Hemis. There are keeper sleeves that hold them up and out of the way so you can pull the cam without pulling the lifters. Pull the rockers, pushrods, and timing cover and when you spin the cam around it will push them up into the keepers so you can pull the cam out. Just did this on my 5.7 not that long ago.
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Did you have to change the springs? Did you notice a difference in the butt dyno?

Edit: Never mind, I read your cam swap post. Car sounds awesome.
 
Buschi340 said:
you didn't change the lifter?
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No need to change lifters in a 6.1 hemi for a cam swap:
-Roller cams DO NOT require lifter changes. Unlike the old school flat tappet cams that do require lifter changes with cam swaps.
-5.7 motors with MDS DO require a lifter change for the MDS cylinders (there are exceptions, but this is a good general rule to follow)

Usually a spring swap is recommended. Which can be done without removing the head. As I'm sure you know, removing the heads costs about $100 in gaskets and TTY bolts, which is why most try to avoid it.
 
Uhcoog1 said:
No need to change lifters in a 6.1 hemi for a cam swap:
-Roller cams DO NOT require lifter changes. Unlike the old school flat tappet cams that do require lifter changes with cam swaps.
-5.7 motors with MDS DO require a lifter change for the MDS cylinders (there are exceptions, but this is a good general rule to follow)

Usually a spring swap is recommended. Which can be done without removing the head. As I'm sure you know, removing the heads costs about $100 in gaskets and TTY bolts, which is why most try to avoid it.
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Guess I should have mentioned I swapped the MDS lifters out way back when I built the engine for the initial swap, so no concerns for me there. You can run MDS lifters, but they're typically not considered quick as strong and a little more limited on the lift they can handle as I understand it.
 
oh, stupid me. I forgot I have now Rollers.... :D thanks for the heads up.

Great, any cam recommendations for street / strip?
 
I'm on the lxforums a lot and know a couple guys that run the srtmax cam by Spartan I believe is the company not sure if it will work with your application but good numbers and sound from it. It's the biggest cam you can run in a 6.1 with stock springs I believe.
 
The company is actually Inertia Motorsports (they also make a cam called the Spartan). I've got an SRT Max Plus in my 5.7 and it's pretty fun. Went that way largely for the sound (it's an old muscle car, it needs to lope like one), though the performance boost is nice too. I'm sure there are other cams out there that are better, the SRT Max is billed as the best you can do with stock parts and computers. Whether that still stands true or not is probably debatable, but it's still a nice cam either way.

If you call Stu down there and discuss your setup he's more than happy to suggest an appropriate cam for the application. Nice guy who's had his hands on plenty of engines, so pretty sure he's got a good idea what he's doing.
 
Keep in mind that most of the aftermarket cams for the hemis have LSA's and grinds that are meant to be utilized with EFI and ECUs. I know comp cams has a few "traditional" grinds for carbed guys, I'm sure others do as well. I'm not a cam expert by any means so I'd definitely make sure whoever sells you a cam knows you are running a carb.
 
Modern Muscle said:
We also offer custom grinds and have done a few for carb applications.
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Chris - the way I see it - the major drawback with the Inertia product is that the cam installs at 114ICL...but the crower cam card says it should go in at 106!

This means that those SRT cams are being run 8 degrees retarded - no doubt to achieve piston to valve clearance.

How do you get around this issue with your cams?

Also....what would be the maximum duration and lift you'd recommend for a 6.1 with factory slugs and lifters - using the PSI 1511 spring?
 
response from inertia:
OK, xv intake and 3.25 ( my first gear ) that gives me a good idea.

on a stock piston engine we can go bigger than about 220 on the intake or we have valve to piston clearance issues so with at 218 intake and 226 exhaust we will have decent torque and still pull and build HP past 6500. Then since your carbed lets do a 108 LSA with the carb and short runner intake. I can run it under 560 lift so we can use stock springs ( I am using PSI 1511 )which are most reliable and the ports don't flow any more past that anyway.
 
Rat Patrol said:
Chris - the way I see it - the major drawback with the Inertia product is that the cam installs at 114ICL...but the crower cam card says it should go in at 106!

This means that those SRT cams are being run 8 degrees retarded - no doubt to achieve piston to valve clearance.

How do you get around this issue with your cams?

Also....what would be the maximum duration and lift you'd recommend for a 6.1 with factory slugs and lifters - using the PSI 1511 spring?
Click to expand...

there is no getting around it



The only thing we can do is run a more aggressive ramp and lift with the PSI

We do have some custom intake lobes that let us advance cam some in the engine



It depends on how big you want to go



The Comp factory 224 cam goes in at 117







 
Modern Muscle said:
there is no getting around it



The only thing we can do is run a more aggressive ramp and lift with the PSI

We do have some custom intake lobes that let us advance cam some in the engine



It depends on how big you want to go



The Comp factory 224 cam goes in at 117
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OK...thx for the confirmation Chris.

Would you say then that most commercial cams that install with factory slugs are going to produce similar results.?... The restriction on duration would seem to say this......
 
Buschi340 said:
this is what our german Moparshop offered me: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=606&sb=2

So I probably go with this inertia cam if modern Muscle isn't come around the corner with an unrefuseable offer... :)
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I am currently running the Inertia SRTMAX PLUS.

Its still making power at 7000 rpm when I hit the limiter.....so running a short runner intake and a retarded cam does seem to effect the power band of these motors.

No point in running mine past 7000 however..... I dont like the thought of draining the pan dry......
 
"Same lobes just a tighter LSA so it should make more torque and be noticably choppier on the idle." Is this cam still usable for the street and every day use?
 
My SRT Max Plus (in a 5.7) works just fine on the street. I tightened the LSA up on mine more to 108 because I wanted the choppy idle, but it hasn't given me any problems. I also run a stick, so it's less of an issue. Autos don't get along with them quite as well without some fairly high stall converters as I understand.
 
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