[Gary H]

Just disassembled a 455 SD engine for a rebuild for a customer. It has a HO 041 HL stamped on the end of it. I assume it's a 041 Ram Air IV spec cam with more lift. Anybody have a old HO spec book that can give me the complete specs? BTW, it used a SD cam core with the small distributor gear on it. Pretty cool!

[steve25]

I believe it’s specs are as in this chart, but this cam has the standard gear.

[PontiacJim1959]

From an early L&M Super Duty Engineering booklet, it says:

"The 041 HL provides the same timing as the famous Ram Air IV cam at .040" lift and also has the closer 110 lobe centers and higher lift, .520 with 1.5 rockers. If the customer wishes to install 1.65 rockers with this cam, lift figures would increase to .572."

Another source says:

H-O Racing HC-03, 041HL, made by Crane, 4,500 - 6,300 RPM

Only shows lift - 1.5 ratio - .500" Int/.504" Ex, 1.65 ratio - .550" Int/.554" Ex.

[Tom Vaught]

I have the same camshaft from HO Racing (Camshaft Machine Company/Crane) except with the normal Pontiac distributor gear diameter. I plan on running it with 1.5 rockers and with Rhoads Hydraulic Lifters. 455 engine.

Tom V.

[steve25]

That second posted lift range makes much more sense since a Hydro Cam with those duration numbers would be right on the edge of failing lobes if it had .520" lift with only 1.5 rockers!

[Gary H]

Thanks for the responses. Can anybody confirm the 110 LSA on it. I'm not a fan of tight LSA's with exhaust manifolds. May stick another cam in it if so.

[sdbob]

I have a new HC 63 here,041HL The single sheet of info states-intake duration-308,lift @1.50-.500- centerline-109. Exhaust duration-320,lift at @1.50-.500-centerline 118. Camshaft phasing straight up, max rpm 6500. Nothing else written.Hope this helps.

[johnta1]

Most of the HO cams I seen were around 112-114 LSA.
(ICL around 109/110)

[Stan Weiss]

Originally Posted by steve25

That second posted lift range makes much more sense since a Hydro Cam with those duration numbers would be right on the edge of failing lobes if it had .520" lift with only 1.5 rockers!

Steve,
While the HO / Crane may will pre-date the Comp Cams. Comp Cams XFI lobe does has 236 @ 0.050" and .518" lift with 1.5:1

Stan

[Formulajones]

Originally Posted by sdbob

I have a new HC 63 here,041HL The single sheet of info states-intake duration-308,lift @1.50-.500- centerline-109. Exhaust duration-320,lift at @1.50-.500-centerline 118. Camshaft phasing straight up, max rpm 6500. Nothing else written.Hope this helps.

LSA with those specs would be 113.5

[Tom Vaught]

Originally Posted by Formulajones

LSA with those specs would be 113.5

Just info to others, the Intake centerline number is not the lobe separation number but if you take the intake centerline and the exhaust centerline and add them and divide by 2 you should be right on the 113.5 LSA number.

(LSA = Lobe Separation Angle)

Tom V.

[Gary H]

Thanks! Then it appears it's 230 I 240 E @.050, lift .500 I .540 E with 1.5 ratio rockers, LSA 113.5*, ICL 109*. If it checks out wear wise I'll probably reuse it.

[Formulajones]

Originally Posted by Tom Vaught

Just info to others, the Intake centerline number is not the lobe separation number but if you take the intake centerline and the exhaust centerline and add them and divide by 2 you should be right on the 113.5 LSA number.

(LSA = Lobe Separation Angle)

Tom V.

Yep that's why I posted that, hoping Gary would see it. As long as those specs that Bob posted are correct, and I see no reason why they wouldn't be, then 113.5 is the LSA. (109 + 118 divided by 2)

[DaleO]

Hopefully you can zoom in to read. These pictures are from the HO catalog.

[KEN CROCIE]

HC-03/63

[formula kid]

The 041HL cam that you are asking about in the HO catalog is the HC-63. That cam is based on the cam that was never installed in the SD-455 that was rated at 310HP. Since you said that the large gear on the cam and the small distributor gear that is what you took out. Specs are as follows intake duration 308, lift @1:50 = .500, lift @ 1.65 =.550, Exhaust duration 320, Lift @ 1.50 =.504, Lift @ 1.65 =.554, and power range 3900-5500. I hope this is helpful

[Gary H]

Anyone know for sure what the duration @.050 numbers are? The numbers Ken Crocie posted above are 244 252. That's a lot more duration than the factory 041 cam which is 230 240 The engine didn't idle like it had the 244 252 number IMO..

[b-man]

It’s more than simply a 041 cam with added lift.

To end up with a decent lobe profile adding duration was part of getting that higher lift，

Personally experienced the HC-03 (it came with the same spec sheet that Ken posted) for 10 years of bracket racing a low-compression 455 with ‘71 197 HO heads. I ran it with 1.65:1 Sig Erson stainless roller rockers that I got from Ken along with the cam.

Powerful and a bit lopey at idle, it really woke up that 8.6:1 455 and made reliable power, had Ken’s Tri-Y headers on it as well. With more compression the idle would have been tamer, it was a perfect cam for my old never rebuilt 455 short block.

[KEN CROCIE]

I know for sure.

[Gary H]

Originally Posted by KEN CROCIE

I know for sure.

OK, thanks!!