[GoreMaker]

Does anyone know which Comp Cams lobe profiles would most closely match the OEM W72 cam lobe profiles (both intake and exhaust)? If they vary from year to year, then I'm specifically referring to the 1977 W72 manual transmission cam.

Or even better, if someone has lobe profile files that were measured directly on a W72 cam (Cam Doctor, Cam Pro Plus, etc) that they're willing to share, that would be awesome.

[pastry_chef]

A source has this.

1977 Manual Transmission W72 Camshaft Specifications
Part # 549431

Intake Duration 274 Degrees
Open 21 Degrees B.T.D.C
Close 73 Degrees A.B.D.C.
Valve Lift .364
Intake Centerline 116 Degrees
Exhaust Duration 298 Degrees
Open 77 Degrees B.B.D.C.
Close 41 Degrees A.T.D.C.
Valve Lift .364
Exhaust Centerline 108 Degrees
LSA 112 Degrees
Overlap 62 Degrees


I've seen .050 duration's noted as 192 / 210

Comps lobes are faster from adv to .050.

[Stan Weiss]

Looks like Pastry Chef / Mike got it.

Cam Quandary
An In-Depth Look at the '77-'79 T/A 6.6 Camshaft Specs

https://www.motortrend.com/how-to/hp...-cam-quandary/

Stan

[Lee]

Bullet has a better selection of HFT lobes. My own low-lift cam uses Bullet lobes.

Bullet and Comp have both been out of Pontiac HFT cores for over 2 months though, so it will be awhile before either can catch up on backorders and get any new orders filled.

[steve25]

That amount of valve lift is pathetic which makes that cam more like a factory 2 bbl cam!
I would use the N522 cam that Ames performance has which is the remake of the factory 066 cam.

And they probably have them in stock to boot!

[Skip Fix]

Stan thanks for the link. I must have missed Rocky's article on those.

[tom s]

Guys,might look at Clay Smith cams.They have had pontiac cores in stock.Just last week a guy I sent there got one.Tom

[John Milner]

Schneider Racing cams also has Pontiac cam blanks. Have ordered 2 within the last year.

[Jay S]

Cam craft would also be worth a call to replicate the 77 W72 4 speed cam, i have never used them but they appear to be able to get close with some of there grinds on vintage cams.

I have a nice original cam from my 4 speed 77 yet. IMHO…The 066 is not a very good replacement, quite a bit smaller than a original W72 cam, won’t have the power up top like the original, and it likely won’t respond to retarding the timing like the original W72 were, not enough exh duration. W72’s seem to have more lift than what I have seen published, the cam specs from my w72 appeared to be the same as 4 speed cam Rocky checked in the article stan linked.

From compcam you could have them dig into there Crane cam library and use a 250/264 from the HP series, 194/208@.050”, .398”/.419” lift, symmetrical profile, would be a close replaction.
HP-194/2564 on the intake, HP-208/2795 on the exh, 112 LSA, Icl 116. But they need a cam core. Bullet was a good option too if they had a core, but, it is hard to find symmetrical profiles like an original cam at bullet, most there profiles asymmetrical.

[Stan Weiss]

I don't know if these are symmetrical profiles. Here is another series of Crane lobes which might work.

Stan

[steve25]

The 066 cam is 197 and 206, so hardly any difference in that regard to the w72 cam, however it has 7 degrees less overlap then the w72 cam which is surprising.
The 067 has 1 degree less overlap then the 066 cam, so is that not a kick!

[77 TRASHCAN]

I had always thought this was the original cam in my 77 TA, 180 HP, 7.6:1 engine??? Is it???
I am wondering why the OP'er is asking??? A W72 restoration???
There's a current thread build, with some modifications making swesome power!!!
I wonder how this W72 cam would fare??? It seems sooo small, but my car DID run quite well with what ever tiny cam it had...
My 400 made good power to 4000, not much above that, though...

[pastry_chef]

Originally Posted by 77 TRASHCAN

It seems sooo small, but my car DID run quite well with what ever tiny cam it had...
My 400 made good power to 4000, not much above that, though...

Even a 350 wants a larger cam for performance. Dynomation info here, it had headers.

Originally Posted by pastry_chef

Pont 350, even with very low CR - 7.6
Best average torque from 2000 to 4500 RPM.
Evaluating from valve open and close, not .050.

Symmetrical -- same lobe for both intake and exhaust.

Ultradyne hyd flat.

H11
266 @ .0045
211 @ .050
123 @ .200

Stock low compression 350 with a cam.
https://www.youtube.com/watch?v=m9dSIUFWNpg
Crane Cam 216/216 .454/.454 110LSA

[tom s]

I have built a lot of 366 type engines and from what I have learned I would not run a engine over a 326 with anything less than a 068-2801.JMHO,Tom

[ponyakr]

Not making any recommendations here & don't know when one of these would be available.

But here are 3 small, low lift Howards cams.

https://www.summitracing.com/parts/h...w/make/pontiac

https://www.summitracing.com/parts/h...w/make/pontiac

https://www.summitracing.com/parts/h...w/make/pontiac

The Melling SPC-4 is also small, & appears to be in stock, ready to ship..

https://www.ebay.com/itm/16506131176...0AAOSwx2lbl1bU

[Stan Weiss]

I don't know if Howards has blanks but they have a nice selection of under 0.400" lift with 1.5:1 rockers.

Stan

[Jay S]

Originally Posted by Stan Weiss

I don't know if Howards has blanks but they have a nice selection of under 0.400" lift with 1.5:1 rockers.

Stan

That is probably the best resource, I forgot about Howard’s. I am pretty sure they have supply issues to though. If you look up the entire list Stan posted, further down on the list they have their replicated lobes for the 066, 067, 068, and 744 all listed for intakes and exhaust.

The intake lobes for the w72 cams are not that special, easily can find a lobe nearly identical for the intake. The exhaust side is what is unusual. 298* of true seat timing for a lobe that only has 210* @.050 was unique to the W72 cams. Only 3* shy of the seat timing rating of an 068. The intake and exhuast closing of the 77 4 speed cam is nearly 10* later on both intake and exhaust, and still 7* to 8* later on the closing side at .050” versus a 066, that is how the w72 cams get the power band higher than similar size cams. But on paper, looking a .050” ratings only, it looks like a cam like 066 would be as big, maybe bigger. A closer look at the closing timing events and it explains how the w72’s ran different than and average engine with a 066 cam. The combination of the long timing on the exhaust and later intake timing made a nice increase in power at the upper rpms. Was a unique and pretty unusual way of finding top end power and at the same time curb lower speed emissions.

[74Grandville]

For my W72 build i installed a Melling Spc-4 (066) but installed it at 112 ICL using a mopar key. this is what DD2000 showed as a good place to act like the W72 cam. I'm very happy with the results. I do have Doug's headers and dual exhaust which i'm sure helps a lot, but it feels like it has power everywhere up to 5,000 rpm. It surprised me for a low compression nothing special build.

[GoreMaker]

Holy crap...

Well thanks for all of that, but I wasn't really asking for cam advice at this time. I just want stock cam lobe profiles. I specifically mentioned Comp Cams because I happen to have most of their current OTS profiles handy and I hoped they had something at least similar that I could grab from. That doesn't appear to be the case.

I find it amazing how quickly a simple cam question devolves into forceful opinions

[pastry_chef]

Originally Posted by GoreMaker

I just want stock cam lobe profiles.

Having those would be nice.
For many historical engine cam lobes.

Blessed with a large lotto win,, I'd be inclined to buy up and scan nearly everything I could get. GM, Mopar and Ford.

I can generate a lobe file having lift at every cam degree but often off a few thousands from reality. Good old "advertised duration" rating variations also limiting what we know.