The Oldsmobile Connection

[blonzz]

Will either of these cams work in this combination?

238°/246° @ .050
.542" Intake Lift
.558" Exhaust Lift
110° Lobe Separation

Or

246°/253° @ .050
.558" Intake Lift
.574" Exhaust Lift
110° Lobe Separation


70 442 Holiday Coupe (curb weight 3817 lbs)
Fresh Engine
470 ci
Performer RPM heads and Torker intake
9.75:1 CR
Pro Systems Pro Series 950 CFM
Pertronix Flame THrower HEI
Thorley headers 1 3/4" tubes 3" collector
Torque Tech 3" X-pipe system w/ 22" large case Aero Chamber mufflers
TCI Turbo 400
10" 2800 RPM stall converter (can be replaced)
4:11 Rear Gears posi
28" tall P275/60R15 Drag Radials

Thanks,
John

[strokercutlass]

John, you didn't specify, but I'll take a guess and assume you're talking hydraulic cams....

I'd say with your compression ratio, you're in the ballpark for either one, although the first cam may be the better choice overall, for a few reasons....

The first cam matches your converter a bit better, and "should" pull better vacuum for power brakes. The gearing looks a bit high for this cam, but the converter and tires you're running should bring it in closer.

The first cam will also have a slightly lower powerband, to bring the torque in quicker.

Looking at some other cam specs I have, heres a general area where you're at with each cam...

cam 1: 2000-6500 rpm powerband, 9-10.5:1 CR, 3000-3200 RPM converter, 3.43-3.73 gear

cam 2: 3200-6800 rpm powerband, 10-11.5:1 CR, 3500-3800 RPM converter, 3.90-4.11 gear

As I said, these are rough estimates, but should be fairly close. What are your plans for the car? If it's more of a driver, the first cam would probably suit the car better, as it will have a better powerband for driveability.

On the other hand, if it's more of a weekend warrior, you could step up to the larger cam and see what happens....

Then again, I run a 12:1 470 with a 304/314, 264/271 @.050, .562/.594 lift solid lifter cam in my 72, which I drive on the street...it's radical, runs a whopping 8 inches of vacuum, had to convert it to manual disc brakes due to no power assist, and costs $4.00 a gallon every time I pull it out of the garage, so what do I know.... :lol:

From a driveability standpoint, I think the smaller cam would be better suited to it, as it would match what you currently have alot better......

Just my.02 cents :wink:

I'm surprised how heavy your car is....my 72 "S" was 3650 last year with a 1/4 tank of gas,vinyl top, full interior, heavy wheels, fiberglass hood, and rear wing. My friends 70 442 is about 3450 with a 10 point cage, full interior, 9" rear, fiberglass hood, deck lid, and spoiler..

[blonzz]

Yes, the cams listed are both hydraulic.

Quote: Then again, I run a 12:1 470 with a 304/314, 264/271 @.050, .562/.594 lift solid lifter cam in my 72, which I drive on the street...it's radical, runs a whopping 8 inches of vacuum, had to convert it to manual disc brakes due to no power assist, and costs $4.00 a gallon every time I pull it out of the garage, so what do I know.... :lol:

Here's a mechanical. How do the numbers look on this.

278° Adv. Intake Duration
286° Adv. Exhaust Duration
244°/252° @ .050
.557" Intake Lift
.574" Exhaust Lift
110° Lobe Separation

What are the differences between running a solid vs a hydraulic cam besides the lifters?

Thanks,
John

[88 Coupe]

blonzz wrote: Will either of these cams work in this combination? Hi blonzz, hello all
I have used various cams from 230* to 274* in several BBO, all (except the 425) configured very similar to yours.
Any of the 3 cams you listed will work with your application, albeit, with more varibles than "Stroker" has mentioned.
My guess is 1 to 2 tenths improvement with the 238°/246° cam and not much more with anything bigger.
You have a good looking (on the outside :lol:) street/strip machine that is (with a little chassis tuning) capable of mid to high 12s, and my advice is to relax and enjoy it.
If you are thinking of trying to improve on what you have, you'll need to start from scratch , set and define your goal, and design the new combo around the cam that will meet that goal.
The best cam choice and total design will be the result of the collaboration between you and your engine builder.
Just to keep things interesting, the 425 in my sig uses an Isky 280H single pattern 230*, .531 lift and 108* LC.
Regards, Norm