[Skip Fix]

"I know now that Butler stopped using UD cams because Harold couldn't keep him supplied"

UD had some business issues and shut the doors is why Butler stopped carrying them. Until Harold settled at Lunati for awhile it was hard to find the UD lobes. And when they were ground at Lunati they did not have as much advance ground into the IC.

[Steve C.]

Here, a 5000 rpm truck motor combination.... 502 hp at 5000 RPM

4.250 stroke / 4.185 bore
Unported Edelbrock d-port heads / 251 cfm at .500" lift
204 cc intake runner volume
9.98 compression ratio
Torker II intake & Holley 750 carb

Comp XR276HR-10 hydraulic roller cam
224/230-degree cam, #79 jets, 34 degrees BT

Dyno Chart:

RPM TQ HP BSFC

3,300 566.7 356.1 0.38
3,400 569.5 368.7 0.38
3,500 570.7 380.4 0.38
3,600 569.3 390.3 0.38
3,700 566.9 399.4 0.38
3,800 565.1 408.8 0.39
3,900 564.2 418.9 0.39
4,000 563.4 429.1 0.39
4,100 562.9 439.4 0.39
4,200 563.3 450.5 0.40
4,300 563.2 461.1 0.37
4,400 563.3 471.9 0.36
4,500 559.7 479.6 0.37
4,600 556.7 487.6 0.37
4,700 554.1 495.8 0.38
4,800 547.3 500.2 0.38
4,900 538.5 502.4 0.40
5,000 528.1 502.8 0.41
5,100 506.2 491.5 0.44
5,200 491.2 486.4 0.45
5,300 487.2 491.7 0.45


Read more: http://www.hotrod.com/how-to/engine/...#ixzz3hbh2nenZ


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[wolf]

Originally Posted by hurryinhoosier62

It's a simple answer: fuel injected engines need LSAs of 112-116 degrees.

Really? Why?

[Steve C.]

From Comp Cams....

8. I’m switching from carburetion to fuel injection. Do I need to change my camshaft?

Quite frankly, it depends on what camshaft is already installed in your engine, but for the most part, yes. The important thing to remember is that factory fuel-injected engines generally require wider lobe separation angles than carbureted engines do. Camshafts with wider LSAs feature decreased overlap, which yields a more efficient combustion process and increased vacuum, which is required by factory engine computers (or “ECUs”).

In order to take advantage of the design characteristics of the high efficiency EFI-style cylinder heads and intake systems, COMP Cams® offers specialized fuel-injection camshafts, such as the XFI™ series. These cams deliver dramatic improvements in performance for today’s fuel injected engines while still satisfying the requirements of sensitive OE computers.

Aftermarket engine computers such as the FAST™ XFI™ system can run cams in street and competition applications that would traditionally be considered suitable for carburetion only, but these ECUs are the exception, not the rule.


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[mike76]

" and when they were ground at Lunati they did not have as much advance ground into the IC "

Can you elaborate on that? I bought the UD 288/296 solid flat from Lunati in 2005. Mike

[67GTO4SPEED]

Originally Posted by Skip Fix

"I know now that Butler stopped using UD cams because Harold couldn't keep him supplied"

UD had some business issues and shut the doors is why Butler stopped carrying them. Until Harold settled at Lunati for awhile it was hard to find the UD lobes. And when they were ground at Lunati they did not have as much advance ground into the IC.

Yeah, that's what I was saying. I was just saying that I know now that Butler didn't necessarily switch because the Comp cams were better. That is what I was led to believe back then.

[Steve C.]

Mike,
Many camshafts have a certain amount of advance ground in. I don't know about Skip's specific cams but the last UltraDyne lobes I ordered from Lunati had 4 degrees advance ground in. It was a solid roller cam. I can't speak for all the origional UltraDyne cams produced from Harold before he closed UltraDyne but the two solid roller cams I purchased from him had 6 degrees advance ground into them.

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[gtofreek]

The ground in advance can be influenced by the cam core.

For example, if the cam was ground on a copper core, the heat treating is a shallow, surface treatment. If the cam is to be ground on a lobe sep pushing the limits of the cam core, then they may not have been able to grind the advance in without fear of grinding through the hardness.

[Skip Fix]

I think Harold on the cam card liked a heck of a lot of advance in the intake lobe also. every real UD I had lots of advance recommended.

[grivera]

Originally Posted by Steve C.

Here, a 5000 rpm truck motor combination.... 502 hp at 5000 RPM

4.250 stroke / 4.185 bore
Unported Edelbrock d-port heads / 251 cfm at .500" lift
204 cc intake runner volume
9.98 compression ratio
Torker II intake & Holley 750 carb

Comp XR276HR-10 hydraulic roller cam
224/230-degree cam, #79 jets, 34 degrees BT

Dyno Chart:

RPM TQ HP BSFC

3,300 566.7 356.1 0.38
3,400 569.5 368.7 0.38
3,500 570.7 380.4 0.38
3,600 569.3 390.3 0.38
3,700 566.9 399.4 0.38
3,800 565.1 408.8 0.39
3,900 564.2 418.9 0.39
4,000 563.4 429.1 0.39
4,100 562.9 439.4 0.39
4,200 563.3 450.5 0.40
4,300 563.2 461.1 0.37
4,400 563.3 471.9 0.36
4,500 559.7 479.6 0.37
4,600 556.7 487.6 0.37
4,700 554.1 495.8 0.38
4,800 547.3 500.2 0.38
4,900 538.5 502.4 0.40
5,000 528.1 502.8 0.41
5,100 506.2 491.5 0.44
5,200 491.2 486.4 0.45
5,300 487.2 491.7 0.45


Read more: http://www.hotrod.com/how-to/engine/...#ixzz3hbh2nenZ


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Seems strong for low compression with unported aluminium d-ports.

[wolf]

Originally Posted by Steve C.

From Comp Cams....

8. I’m switching from carburetion to fuel injection. Do I need to change my camshaft?

Quite frankly, it depends on what camshaft is already installed in your engine, but for the most part, yes. The important thing to remember is that factory fuel-injected engines generally require wider lobe separation angles than carbureted engines do. Camshafts with wider LSAs feature decreased overlap, which yields a more efficient combustion process and increased vacuum, which is required by factory engine computers (or “ECUs”).

Well that reads like it's still from a 1988 catalog, where recalibrating the OEM EFI wasn't an option, but that's just not the case anymore. Hurryinhoosier62 made the blanket statement that "fuel injected engines need LSAs of 112-116 degrees", and didn't specify "factory" EFI with the OEM calibration, so I was preparing to disagree with that statement. I've had a 106 LSA cam in my EFI Stock Eliminator car since the mid '90s and the National Records it set can attest to how well that cam works, but of course it's with a proper EFI calibration. I've done a ton of EFI calibration work over the years for tighter LSA cams with both Speed Density and Mass Air OEM systems and it's not that difficult to make them work. Now, would I want a 106 LSA cam in a street car? Hell no. But my point is a tight LSA cam has it's place, and can absolutely work with EFI.

[grrrrregg!!!]

I've never used the 041 cam, but I have used 2 bigger cams than the 041 in a 455 with less than 9:1 compression. Ran the H-O Racing HC-02 (231/243,.512"/516" w/1.65 rockers) and the HC-03 (244/252, .550"/.554" w/1.65s). Only ran the 02 cam for a short time before switching to the 03 cam, in a standard-bore 455 with #197 HO heads at around 8.6:1. It ran great and had low vacuum at idle as expected, manual brake car so it didn't matter.

Sure, higher compression would have been better, but in my situation I was using the parts I had on hand along with the camshaft recommendations straight out of the H-O Racing catalog. The HC-03 was recommended for the 455 HO (a known low-compression engine, right?) with lower gearing, I was using 3.89 cogs with a 28" tall tire:http://forums.maxperformanceinc.com/...5&postcount=19[/QUOTE]

b-man, would you run the HC-03 again today
I have an HC-63 cam I am holding on to for my Super Duty, I believe it spec's out the same as the HC-03, I was considering this cam for my Super Duty. Would anyone this cam today. With 1.50 rockers it seems close to the 041. Does anyone know the specs on the original SD cam for 73 that got axed.

[Skip Fix]

The 288/296 on a 112(still new in box) and 304/312 pn a 112 I have from UD both are spec'd a 106 IC. The 288/296 on a 108 at 102. So genaerally 6 degrees advanced if from UD. The 296/304 on a 112 in my current pump gas I got from Lunati when Harold was there was spec'd for a 108 IC.

[Tinkerer]

Can a direct comparison be made regarding valve overlap between the tight LSA fast ramp cams and the lazy lobes on a wider LSA?

I am finding that even though the fast ramps in question (XE's et al.) have a tight LSA, there is less valve overlap than the lazy lobes with the longer seat timing. Would not the short overlap cams be smoother at low rpms?

Or is the short overlap offset by the faster valve opening, therefore there is actually more flow during the overlap despite it being short?

I understand the issue with the early intake closing event and the noise created by the fast ramp design. However, I would like clarification regarding the overlap. There is much said in the negative for a tight LSA, but with the fast ramps, the overlap is actually less (by the numbers) than the wide LSA-lazy lobe configuration.

For example:

SPC-7 (which I currently have in my 455)
212/225 @ .050"
Intake closes at 75.5 ABDC
Overlap 60.5
LSA 115.5


XE268
224/230 @ .050"
Intake closes at 60 ABDC
Overlap 54
LSA 110


Thanks,

Bill

[Bobs78TA]

Thanks for an informative thread on cam selection for a Pontiac 455. When I called about a cam with PB,PS, AC, etc., I was recommended to use a UD 288/296 HR. I had it ground on a 112CL to reduce the lopey idle. Skip, I'm interested in your combo has you have a UD HFT very close to my specs. You have about 5 more degs. duration @ 0.050", but the roller has 8 more on intake and 1 more on exhaust @ 0.200". ICL is 106 degs also. I would like to communicate further with you regarding your combo outside of this thread if possible.

[Jim Moshier]

Wow, what a great read. A lot of good information....thanks for everyone's input and questions it helped me in my quest for knowledge. now to decipher it all! :-)

[hurryinhoosier62]

Originally Posted by wolf

Well that reads like it's still from a 1988 catalog, where recalibrating the OEM EFI wasn't an option, but that's just not the case anymore. Hurryinhoosier62 made the blanket statement that "fuel injected engines need LSAs of 112-116 degrees", and didn't specify "factory" EFI with the OEM calibration, so I was preparing to disagree with that statement. I've had a 106 LSA cam in my EFI Stock Eliminator car since the mid '90s and the National Records it set can attest to how well that cam works, but of course it's with a proper EFI calibration. I've done a ton of EFI calibration work over the years for tighter LSA cams with both Speed Density and Mass Air OEM systems and it's not that difficult to make them work. Now, would I want a 106 LSA cam in a street car? Hell no. But my point is a tight LSA cam has it's place, and can absolutely work with EFI.

Closed lop or open loop? MOST factory EFI systems with closed loop can't "keep up" with a tight LSA. Most cam manufacturers advise you to stay with a loose LSA IF you're running an OEM closed loop system. I could be wrong, but I believe most aftermarket EFI systems recommend an LSA of 112-116 degrees as well.

[1funride]

Ran a model of the UD 288/296 110 and the Crower 60919, the curves pretty much overlay one another. This with a 462, 10.5:1, dual plane, both with 1.65 rockers, and stock edlebrock D ports flowing 262 @ .600 and 157 @ .600 (as per Edelbrock literature). These cams seem to perform about the same, build torque about the same, and fall off about the same. I believe the 60919 is the bigger cam and has always been recommended with rhodes lifters especially in this thread. This thread seems to indicate the 288/296 has better street manners.

Q: Is my observation of these cams being essentially the same performance wise correct for the above example?

Q: Is my observation of the 288/296 110 being more street friendly correct?

I have 90% of the items to build my 462 this winter, which includes the 60919, edel heads, crower hft lifters, performer rpm intake, etc sitting on the shelf. The car has a 2500 stall (possibly to small for the 60919), and 3.42 gears. Its a 68 firebird.

After reading this I have a little reservation on using the 60919 with the 2500 converter, 3.42 gears, and standard HFT lifters (the ticking will drive me nuts). Will the UD grind suit a little better without the use of rhodes on the 60919?

[Cliff R]

Rhoads lifters are NOT required with the 60919 camshaft in a 455 with 10 to 1 or higher compression...IMHO. I ran that cam in my last 455 without them for quite a few years and it was fine. I installed them late in the life of the engine just to see what they would do.

I saw right at 2" more vacuum at idle speed, and smoother right off idle. The car ran exactly the same at the track, probably due to the 10" converter that flashes to about 3500rpm's.

That engine was 468cid, 10 to 1 compression, and it made about 10" vacuum at 750rpm's. With the Rhoads lifters right at 12", and noticeably smoother. The base timing was only set at 10 degrees BTDC.

We also built a 455 with unported 87cc Edelbrock round port heads, and the 60919 camshaft. It made 505hp on the dyno and put a 3900lb Firebird to 11.50's at 118mph in full street trim, driven to the track. I consider that pretty stout performance for unported heads and a pump gas street driven combo.......Cliff

[Steve C.]

To add to the confusion you can also throw the Lunati Voodoo hydraulic flat tappet lobes into the mix....

Part Number: 10510704
( Previous Part Number: 60904 )
Advertised Duration (Int/Exh): 276/284
Duration @ .050 (Int/Exh): 233/241
Gross Valve Lift (Int/Exh): .504/.527
LSA/ICL: 110/106

Similar .050" duration as the UD 288/296 & Crower 60919 cams but with less seat timing and additional valve lift. And some will suggest the Voodoo lobes are quieter than UD grinds, and especially the Comp XE lobes.


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