[Steve C.]

In addition the XR276HR cam is rated with 224 degrees intake duration at .050" lift and the OF hyd roller has 236 degree intake duration at .050".

.

[STEELCITYFIREBIRD]

Out of respect for the OP, he just wants to get his car running well, wayyy to much info, he stated keep it simple.
3k to spend, a roller setup likely won't fit in that budget.

[pontibeast]

[QUOTE=pastry_chef;5712940]I can provide some clarity.

The Comp 276 hyd roller has 145 duration @ .200.
The Old Faithful roller has 160 at .200

Comparing these to Comp's dual energy hyd FLAT tappet-
Lobe 5002 , duration's are
283 adv
233 .050
146 .200

NOTE the flat tappet has MORE duration at .200 than the small roller in Cliff's favorite chart he has thrown up for years.

That 455 was starving for air, so throwing a HUGE lobe area increase greatly helped power output.
Ignore the LSA in that test.

Are you planning on being an asshat for all of your time here? I get it you disagree with Cliff, but you don't have to be such an argumentative prick about it. Lighten up and post up all the results you have had with engines you designed, built and dyno'd. I don't know why the mods let you go on trying to start **** here but I am done listening to your BS without mentioning it.

[tom s]

FWIW,I built a 455 with bone stock 48 heads,not port matched heads or stock intake.9.5CR with custom dished pistons.I put it together with used parts I had in my garage.Used the 276 cam on a 110,broke it in on Joe Shermans dyno with no tuning and it made 432 HP.Not sure what stock 48s flo,Im actually putting the OF2 cam in it now.Will report back when I get it on the dyno.Tom

[pastry_chef]

Originally Posted by tom s

FWIW,I built a 455 with bone stock 48 heads,not port matched heads or stock intake.9.5CR with custom dished pistons.I put it together with used parts I had in my garage.Used the 276 cam on a 110,broke it in on Joe Shermans dyno with no tuning and it made 432 HP.Not sure what stock 48s flo,Im actually putting the OF2 cam in it now.Will report back when I get it on the dyno.Tom

Any detonation?

[Steve C.]

Gez, how was it argumentative ? He was pointing out a possible reason why the larger cam made 90 additional horsepower. And no disrespect to Cliff intended but I threw in my thoughts indicating big differences between the two cams.

It got complicated here once he was told to throw his cam into a dumpster


.

[pastry_chef]

Originally Posted by pontibeast

you don't have to be such an argumentative prick about it. .

The facts are what they are.
I'm only as "argumentative" as I'm forced to be.
Someone who pushes hard with attitude will be slammed back double with truth.

[slowbird]

Originally Posted by Steve C.

In addition the XR276HR cam is rated with 224 degrees intake duration at .050" lift and the OF hyd roller has 236 degree intake duration at .050".

.

I didn't realize it was that small, my mistake.

Back on topic, i would assuming anyone wanting the thumper cam is looking for a rougher idle, correct? With that said the cam chosen here does seem too small for good power. I would probably swap cams and then take it some where to have it "tuned" once running. Don't take it back to the shop that tried to tune it the first time as they don't sound like they are very good imo.
Fwiw i have had bigger cams with tighter l/s on the street that idle good imo, yes the vacuum was lower (we don't have power brakes so don't care), but they idled just fine at 800rpm and would idle down to 500rpm if i really wanted it "lope". We've done it with tri-powers and Holley carbs, maybe a Q-jet can't deal with that situation very well??

[tom s]

No detonation,pumped 175-180.Ran on 91 gas both on the dyno and in my 69 bird.When it goes on the dyno it will have long branch manifolds instead of the headers.Just want to see what I will be looking at when its in the car.Will run the factory intake and carb and then run a HSD and a 800 Holley road race carb.Tom

[Cliff R]

"I find that test very hard to believe Cliff.
Can you guarantee that the first cam was degreed correctly?"

"That brings up the question, Cliff were you present when Kauffman did the dyno testing ?"

Steve, the dyno testing was done in another shop, not at KRE, with absolutely ZERO engine building experience with Pontiac engines. They simply purchased a "stroker" kit for a 400 block, zero decked it, ported a set of #96 heads to 250cfm, called Comp for a cam who sent the XR276HR, and then found out that it not only didn't make much power, it pinged hard enough on the dyno to require rod bearing replacement!

It's is very good test, and simply shows us how the wrong cam leaves a butt-load of power on the table, and can get into trouble quickly with pump fuel, even below the proverbial "brick wall" of 9.5 to 1 with iron heads.

I was glad that it wasn't built here, dyno'd at KRE, and I had nothing to do with it other than to recommend a much better cam with better lobe placement, and YES, both cams were degreed. The XR276HR was set at 106ICL, the new custom ground 236/245/112 cam at 110ICL.

If you haven't had the opportunity to tune a 455 with moderate compression using the XR276HR cam and the OF cam on a 114LSA, then you shouldn't run your mouth on here speculating about idle quality compared to the larger OF clone on a 114LSA.

LSA is also a BIG player with these things. For sure not a "deal breaker", as there are other contributing factors involved with camshaft selection and lobe positions, as has been mentioned a few times, mostly by folks who "can't see the forest for the trees", and can't look at two dyno sheets and simply admit that the bigger cam on a wider LSA was a "home-run", and the smaller cam on tighter LSA a complete TURD and failure in every respect.

Anyhow, when you go to tighter LSA, the lobes are pulled closer together, so overlap increases. You can still put the ICL wherever you want to. We've used custom ground roller cams on 110LSA many times and set the ICL at 110, with great success I might add, but they were all "race" applications. For street 455's we stick with 112 for the vast majority of them, and once in a while 114LSA if they are lower in compression than we typical like to run, like the 455 HO and 455 Super Duty engines, for example.......Cliff

[pastry_chef]

Originally Posted by tom s

No detonation,pumped 175-180.Ran on 91 gas both on the dyno and in my 69 bird.When it goes on the dyno it will have long branch manifolds instead of the headers.Just want to see what I will be looking at when its in the car.Will run the factory intake and carb and then run a HSD and a 800 Holley road race carb.Tom

Thank you Tom.
That is a result I would expect with those parameters.
No less with the legendary Joe Sherman at the dyno controls.
Not some backwoods shop.

[Cliff R]

"We've done it with tri-powers and Holley carbs, maybe a Q-jet can't deal with that situation very well??"

Exactly the opposite. The Q-jet has a built in idle air bypass system that is EXCELLENT. Instead of having to drill the throttle plates to lower throttle angle, air is routed in between the airhorn and main casting thru voids and brought in under the throttle plates. It is a very precisely controlled vacuum leak, and when the rest of the idle system is opened up correctly, idle with HUGE cams and very little vacuum is no problem at all using a Q-jet....FWIW......Cliff

[pastry_chef]

Originally Posted by STEELCITYFIREBIRD

Out of respect for the OP, he just wants to get his car running well, wayyy to much info, he stated keep it simple.
3k to spend, a roller setup likely won't fit in that budget.

Agree.

In the OPs place I'd be calling SD Performance for a set of KRE 295 Dports
http://www.sdperformance.com/viewPro...productID=1691

So many benefits with one hit!
No to stock heads, I wouldn't port the 62's

[Steve C.]

Cliff, Sorry for any confusion. I just assumed they were KRE dyno sheets since there are no scfm numbers. I know KRE does not use a "bell" above the carburetor thus no turbine to generate scfm numbers.


.

[pontibeast]

Originally Posted by pastry_chef

The facts are what they are.
I'm only as "argumentative" as I'm forced to be.
Someone who pushes hard with attitude will be slammed back double with truth.

I said what I felt had to be said. I am not turning this site into Yellow Bullet, you slam back all you want with the truth as you know it. I'm done f'ing up this great site with this kindergarten crap.

[tempest1964]

Geez, glad I don't haunt "Yellow Bullet" site. I like discussions to be on an Adult level. No cursing, even with hyphens. Lol

[ponyakr]

Originally Posted by tempest1964

Geez, glad I don't haunt "Yellow Bullet" site. I like discussions to be on an Adult level. No cursing, even with hyphens. Lol

LIKE !

[gtofreek]

Originally Posted by pastry_chef

I can provide some clarity.

The Comp 276 hyd roller has 145 duration @ .200.
The Old Faithful roller has 160 at .200

Comparing these to Comp's dual energy hyd FLAT tappet-
Lobe 5002 , duration's are
283 adv
233 .050
146 .200

NOTE the flat tappet has MORE duration at .200 than the small roller in Cliff's favorite chart he has thrown up for years.

That 455 was starving for air, so throwing a HUGE lobe area increase greatly helped power output.
Ignore the LSA in that test.

Furthermore Cliff notes the smaller roller had worse idle.
Idle quality is reduced with increased valve overlap area, not purely LSA
The OF cam opened the intake earlier and closed the exhaust later, way more overlap!

Actually, it's just the opposite, spreading the lobe sep out opens the exhaust valve earlier, and the intake valve later. So it reduces overlap if the duration remained the same. With narrow LSA the intake opens earlier, and the exhaust opens later

[pastry_chef]

Originally Posted by gtofreek

Actually, it's just the opposite, spreading the lobe sep out opens the exhaust valve earlier, and the intake valve later. So it reduces overlap if the duration remained the same. With narrow LSA the intake opens earlier, and the exhaust opens later

I stand by my comment that is correct.
I was not talking about IF duration was the same.

I agree, GENERALLY with narrow LSA the intake opens earlier, and the exhaust opens later. Obviously exact centerline's and duration's factor here.

XR276HR

Adv duration 276° / 282°

110 LSA

Per Cliff was set to 106 intake centerline.

Intake open at 32 BTDC

Exhaust close at 27 ATDC

Overlap = 59
-----------------------------------------------------

Old faithful - on 114 LSA

Adv duration 289 / 306

Was set at 110 intake centerline.

Intake open at 34.5

Exhaust close at 35 ATDC

Overlap 69.5

[gtofreek]

I guess I misunderstood your comment. I thought you were making a general statement about LSA's. My mistake.