C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

Cams

 
Old 03-15-2019, 04:36 PM
  #41  
htown81vette
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Originally Posted by NewbVetteGuy View Post
but I'm just not clear how much it actually gains you in terms of performance; what it COSTS you in terms of $$$ is pretty obvious. I'm a little skeptical that the cost diff will be overcome.
I think the cost difference is $300 more than the equivalent roller cam, and they claim 8 hp more. So that works out to $38 per hp which is not bad. For a stroker with a dual plane manifold can't hardly go wrong with this cam. And especially for C3's many of us want it to fit under the stock hood, therefore we try to stick to dual plane manifolds. That's what drove me this direction....

NASCAR had been using this technology for years before Comp Cams starting selling it.....
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Old 03-15-2019, 04:37 PM
  #42  
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Check this out:

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Old 03-15-2019, 05:16 PM
  #43  
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Originally Posted by cuisinartvette View Post
Most intakes will vary runner to runner, even EFI wih the TB up front, dual & single planes etc.
Just an opinion but I think its almost a benefit when some runners are longer than others on a street car
To help keep the powerband wide?

-So hilarious to see your name pop up on multiple engine threads across multiple forums/sites today! -It's like you're everywhere on the internet at the same time! ;-)


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Old 03-15-2019, 06:56 PM
  #44  
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Adam,

Don't you find it really odd that a blueprint 383 with a flat tappet cam makes 420 Gross HP/450 Gross TQ with a very low lift cam .480/.486 inch and the blueprint 383 with a roller cam with much more lift:

Cam Type: Roller
.528 Intake .536 Exhaust
221 Intake / 226 Exhaust duration
@.050 - 110 degree lobe separation

makes only 10 more gross HP and the same torque with a roller cam? Seems like something is not right on the specs or their heads are just at max flow with sub .500 lift cams and the bigger roller cam is not worth much more with the limitations of the heads? My 355 with roller cam and AFR heads is making the same numbers as the blueprint 383 so the heads must be the limiting factor on the 383.

Last edited by jb78L-82; 03-15-2019 at 06:59 PM.
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Old 03-15-2019, 07:00 PM
  #45  
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Adam, too much free time last few yrs (not by choice), engine tech is always a fav.
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Old 03-15-2019, 07:19 PM
  #46  
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Originally Posted by jb78L-82 View Post
Adam,

Don't you find it really odd that a blueprint 383 with a flat tappet cam makes 420 Gross HP/450 Gross TQ with a very low lift cam .480/.486 inch and the blueprint 383 with a roller cam with much more lift:

Cam Type: Roller
.528 Intake .536 Exhaust
221 Intake / 226 Exhaust duration
@.050 - 110 degree lobe separation

makes only 10 more gross HP and the same torque with a roller cam? Seems like something is not right on the specs or their heads are just at max flow with sub .500 lift cams and the bigger roller cam is not worth much more with the limitations of the heads? My 355 with roller cam and AFR heads is making the same numbers as the blueprint 383 so the heads must be the limiting factor on the 383.
The HP difference I don't find that surprising because the roller cam has 8 degrees less @ 0.050" so it's HP peak is at a lower RPM than the flat tappet motor AND still has 10 HP more. (If it was a roller cam with 229 / 230 @ 0.50" duration and was an apples to apples comparison then the HP would be more confusing) -Normally I'd model them both, but with the critical cam specs missing it's all guess work and I just don't have enough experience to trust my guesses too much.

The max torque being the same is a little strange, but the diff in lift between the two engines isn't that big of a difference especially when it looks like the air flow isn't much different between the two lifts on those heads.
-I would be ABSOLUTELY shocked if the low RPM torque were close to one another, though. (The roller cam should have a smaller advertised / seat-to-seat duration and therefore have a higher dynamic compression ratio and a better bottom-end.) I was shocked that they recommended the same TC Stall for both engines (I would've expected the roller cam to have a 500 RPM lower TC rating)

BluePrint provides dyno sheets for each motor, though so I doubt them fudging the #'s would be a good idea...
I'd love to see the dyno comparison between the two if anyone's got them...


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Old 03-15-2019, 09:19 PM
  #47  
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Originally Posted by John Swift View Post
My engine is Hydraulic Flat Tappet!
Correct but you don’t have to stay hydraulic. This is an old article but it gives you the jist of what it would take to convert a non roller motor to a roller motor. Not gonna get into the pros and cons of roller vs flat tappet (that’s literally an entirely different out of control thread) but you shouldn’t rule out an option based on the fact of what you “currently” have unless budget or something else is the driving force. If you want something pretty agressive duration and lift wise I would definitely look into a conversion. http://www.superchevy.com/how-to/148...ic-roller-cam/
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Old 03-16-2019, 07:50 AM
  #48  
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Originally Posted by kossuth View Post
Correct but you don’t have to stay hydraulic. This is an old article but it gives you the jist of what it would take to convert a non roller motor to a roller motor. Not gonna get into the pros and cons of roller vs flat tappet (that’s literally an entirely different out of control thread) but you shouldn’t rule out an option based on the fact of what you “currently” have unless budget or something else is the driving force. If you want something pretty agressive duration and lift wise I would definitely look into a conversion. http://www.superchevy.com/how-to/148...ic-roller-cam/
FWIW-I did the roller conversion in 2014 for my OEM L-82 and the it was so much easier than what I read it to be and what many said on this forum. It is not hard nor does it require any special skill...essentially much of the conversion complication is hype...makes me wonder.

Here is basically what needs to be done:

1. Buy a quality roller cam cam from a known vendor like Howards which is what I used
2. There is no longer any issues with a fuel pump special rod or special distributor gear using Howards roller cams. I am still using my OEM fuel pushrod and OEM distributor gear
3. Because the C3 water pump sits directly against the OEM timing cover, the roller cam button is an easy install, requiring a simple slight dimple to the the timing cover to accommodate the nylon cam button. There is no special measuring required to achieve the cam from walking forward. This step has been completely overcomplicated when you get advice and read the literature. The point is to provide a leverage point to prevent the cam from walking forward and in combination with a double roller timing chain CANNOT walk forward, if done correctly, which is simple.
4. Measuring the pushrods requires some attention to detail but relatively easy as well. I called Howards for the preload measurement of their roller lifters and then measured using a pushrod checker so that the roller tipped lifter was centered on the the valve tip with an equal sweep (some of the theories on this procedure is ridiculous as well)..pretty easy and then subtracted the lifter preload to determine my pushrod length to order. I did not use checker valve springs (I thought this through thoroughly and could not understand why I could not use the installed springs as long as I knew the lifter preload-howards agreed as well) since you don't need to if you know the lifter preload when filled with oil and using the installed valve springs. It worked perfectly and is still perfect 5 years of driving. This step is overcomplicated by so many and seems purposely confusing by many. It is not.

That is it!

Last edited by jb78L-82; 03-16-2019 at 07:55 AM.
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