[Green Hornet]

I've got a sweet running 74 350 2bbl..(46 headcast)..in a bird......and want to wake it up a bit.

Not looking for any silly horsepower #s......Q-jet....aluminum intake....and a cam upgrade is in the works..

Have a new Mellings 068 blueprint in the box....

I've run them in 400's and 455's before..but not in a 350....

Were they used in the 68/69 350HO....or was that the 067?

Any input is appreciated..

[steve25]

Yes, the 068 came was used in the high compression 1969 350 HO motor, there was no 68 HO option on the 350, just the 400.

Here is the HO racing recommendations for Cams to be used in high comp motors of which your 74 is not.

If you run the 068 Cam in your low comp motor you will definitely want to advance it the two degrees this cart calls for, and maybe even 4 degrees if you have under 3.23 rear gears out back.

Note the rear gear recommendations !

New springs and valve O-ring seals should be installed at this time also, and lay a straight edge across the top of the rocker studs to check for any that maybe pulling out already, no less when you beat on the motor more!

I wise person at this time would take the added time and effort to install a 60 psi oil pump in place of the stock 40 psi one and a HD pump driveshaft .

All 2bbl motors never came with the great GM Moraine 400 type bearings.
2bbl motors where fitted with lesser quality bearings since they where seen by the factory engineers as far less likely to get beat on by there gas mileage concerned owners.

Horse power you ask?

With this Cam swap you will be trading off low speed torque for greater upper mid range and top end, but you will not however achieve the 320 hp of the stock 69 HO motor, especially since your casting number 46 heads only have the 1.66" Exh valve.

[Kenth]

At least Pontiac thought they had a 350HO engine for 1968, although some may not have heard of these.
Engine codes WK (M/T) 10.5 C.R., 067 cam, #18 heads and 7028269 Quadrajet and YM (A/T) 10.5 C.R., 066 cam #18 heads and 7028266 Quadrajet.

[Tom Vaught]

I agree with Kenth.
I tore down a couple of 1968 350 HO engines in 1970 (when at the university) and one had the 066 camshaft.

We had a class on Engine Design & Assembly and were required to disassemble the engines, take measurements, reassemble the engines, and run them on a engine test stand. One of the engines (for the class was donated by GM Engineering and was supposed
to be the 350HO engine). The second engine was owned by a friend and installed in his Firebird. He later tried to run a RA-IV
camshaft in that engine on the dyno, (posted about this in the past), and the engine was a dog throughout the rpm range.
Neither engine had the 068 Camshaft installed right from the factory.

The 068 camshaft was a very nice camshaft in the larger 389 and 400 engines.

Just my experience on the subject.

Tom V.

The dyno engine even had aftermarket pistons installed before the dyno test (except that the pistons were made with the wrong bore size/clearance and seized in the block). Posted about that too.

[nytrainer]

Not sure how the 067 would work with the lower compression of a ‘74 350. Works well in my ‘68 350HO engine (factory Muncie). Hear it idle below in my signature.

[Green Hornet]

Originally Posted by nytrainer

Not sure how the 067 would work with the lower compression of a ‘74 350. Works well in my ‘68 350HO engine (factory Muncie). Hear it idle below in my signature.

I know the 068 works well in the later lower compression 400...as it actually builds compression...I am told...

Is there a blueprint grind of the 067 available?....I like to run OE cams....

[Green Hornet]

For the non-believers...

350HO is listed on the window sticker

https://bringatrailer.com/listing/19...c-firebird-20/

[steve25]

Just for the record, the last time the 067 cam was used in a 350 was in 1969 and even then it was only used in auto trans version of the HO motor in the A and F body cars, even the 1974 350 in the GTO only got stuffed with the 066 cam which should tell you something about low compression and the common rear gears used in those cars!

In terms of the comment in post 6, “builds compression” compaired to what the 744 or 041 cam, of course!

[PONTIAC LARRY]

Originally Posted by Green Hornet

I've got a sweet running 74 350 2bbl..(46 headcast)..in a bird......and want to wake it up a bit.

Not looking for any silly horsepower #s......Q-jet....aluminum intake....and a cam upgrade is in the works..

Have a new Mellings 068 blueprint in the box....

I've run them in 400's and 455's before..but not in a 350....

Were they used in the 68/69 350HO....or was that the 067?

Any input is appreciated..

If your not swapping heads to improve the factory rated 7.6:1 CR then I would do no more than a oem #066 cam to swap in with 4 barrel etc. Best thing would be to grab some other small valve heads with smaller chambers that have all the exhaust bolt holes like common 68 #17 350 heads. would pump you up a point to a point half and then a 068 cam could be used. 68 320 hp 350 was a small valve 10.5:1 with #18 heads rated 10.5 w 66cc chambers. Wish I had kept the engine I had. They used 066 w auto and 067 with stick, the hotter big valve 69 350 HO rated 330 hp had the 66cc version of #48 heads and 067 cam auto / 068 cam stick .. or even get frisky and rebuild it with a 4.0" stroker kit and make a 383 out of it

[PunchT37]

Or save the 068 and run a small Voodoo cam to build some cyl pressure.

[Formulabruce]

You can get an additional 55 Torque, and 50 Hp by putting on a set of 11 heads. Leave the intake,carb, etc. You will have almost same valves, and be going from 7.4 cr up to 8.8 cr.
The Torque is amazing and is in the RPM range you drive in.
Trying for more HP in a Rpm range you don't use 99% of the time, is a huge waste of money.
The torque will plenty fun enough going to a cruise night.

[Green Hornet]

Originally Posted by steve25

In terms of the comment in post 6, “builds compression” compaired to what the 744 or 041 cam, of course!

That's what Pete McCarthy told me...when we were discussing Pontiac camshafts about 25 years ago..

I just assumed he knew what he was talking about...

[Formulas]

I have used the 068 / 350 engine with both #47 and #48 heads both are better heads on a 350 than yours,
You will not like off idle response,
I replaced the 068 with a 2801 summit cam which was a good compromise between low RPM torque and upper end power,
But however your heads are lower compression than both of mine a 2800 summit cam or a new small Voodoo is where I would be with your stated goals and current parts

With and engine like yours pay attention to advertised durations

[Green Hornet]

Originally Posted by Formulabruce

You can get an additional 55 Torque, and 50 Hp by putting on a set of 11 heads. Leave the intake,carb, etc. You will have almost same valves, and be going from 7.4 cr up to 8.8 cr.
The Torque is amazing and is in the RPM range you drive in.
Trying for more HP in a Rpm range you don't use 99% of the time, is a huge waste of money.
The torque will plenty fun enough going to a cruise night.

I've driven a few 70's and 72 base birds...with stock 2bbl...and I gotta say...the bottom end IS impressive.

I do have some 11's here I believe.....but wanted to run a 4bbl......with a shaker hood...

Not sure if the shaker will line up on a 2bbl....or if I even want it...

[PunchT37]

Run the 11`s with the 4 bbl. No problem.

What gears you running? Auto or stick?

[se428bandit]

I ran a 068 adv 4 degrees in my 1972 350 with 7H1 heads that were cut to a 86 cc (91 is stock) in my Ventura.
It ran 15 flat with a 2.73 gear, i put a 3.23 gear in it (single track rear) and a 2400 convertor and i got it down to a 14.30. It had more in it, the stock center dump manifold was killing it up top. Personally i think the Summit 2800 cam would be a better fit. https://www.summitracing.com/parts/sum-2800
https://youtu.be/RGeBYwmWDNw

https://youtu.be/P7S38kFsIq8

[77 TRASHCAN]

I agree with posts 8 and 9.
The 066 cam is what I would use, it will likely be the least expensive cam to buy, also. Sealed Power number CS641.
Unless you do something to get the compression, at least over 9:1, the power level won’t be much .

[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

112 LSA - 108 IC

0.441 valve lift with 1.5 rocker.

[steve25]

The golden rule of Thumb here is that it’s best to be slightly under Cam’ed then over Cam’ed.
Rebuilding your #11 heads and running them alone no less if you add shorty headers will pick you up far more power everywhere in the motors rpm range with no down side!

[unruhjonny]

I have heard people strongly advise against going to that big of a cam for a P350 without a significant compression bump from where you're at.

I am incline to agree that I wouldn't change the cam, I would instead look for some pre-1971 smaller CC heads - you can get the small valve heads often for a VERY reasonable price.
I have owned several sets of 17 heads over the years.
More compression, and a proper 4bbl swap would probably yield best results over doing a cam swap.