Cam sizing

[silver_bullet]

My! What a big stick!

[silver_bullet]

I have 4 of them, all with a selection device that is operated from inside the cabin.

sounds like auxilliary anti theft device to me....

[SuperBuickGuy]

Lunati doesn't mess around.

[silver_bullet]

Lunati's Voodoo series of Solid Roller camshafts deliver more area under the curve than any other series of Hydraulic camshafts. This means more throttle response, quicker acceleration, more vacuum, better efficiency, combined with maximum horsepower and torque!Solid Roller Cam. Good cam for street/strip applications. Good mid range and excellent upper RPM, torque and HP. Works well in 454 c.i. motors. Needs 2800-3200 RPM stall converter, headers, 10:1+ compression ratio and 3.90+ gearing. Rough idle.

• Advertised Duration (Int/Exh): 273/279
• Duration @ .050 (Int/Exh): 243/249
• Gross Valve Lift (Int/Exh): .655/.663
• LSA/ICL: 110/106
• Valve Lash (Int/Exh): .018/.018
• RPM Range: 2600-6800
• Includes: Cam Only

Part Number: 40110732
Previous Part Number: 60232
$1010 for cam, springs, lifters and timing chain.

My, what a big stick!

[SuperBuickGuy]

Jones Cam
Here's what I recommend.
Cam# BBCR, R78421A-80412-108
261/268 @.050"
.421"/.412" Lobe Lift
108 LSA
Price: $529.83

You'd need to switch to a spring with around 240# on the seat, and 600# at max lift.

.715/.700 lift at the rocker tip dang. It's interesting that this one seems to preserve compression - 'normal' is longer on the intake, shorter on the exhaust...

[cstmwgn]

PAC 1243 springs fit that bill. Similar cam in my engine except I run solid not juice. Works very good in big engines

On Ford engines they tend to use longer duration on the exhaust to make up for poor exhaust port performance. Not sure what you are running but if you percentages between intake and exhaust are very good you might not need as much spread.

[silver_bullet]

Lunati's Voodoo series of Solid Roller camshafts deliver more area under the curve than any other series of Hydraulic camshafts. This means more throttle response, quicker acceleration, more vacuum, better efficiency, combined with maximum horsepower and torque!Solid Roller Cam. Good cam for street/strip applications. Good mid range and excellent upper RPM, torque and HP. Works well in 454 c.i. motors. Needs 2800-3200 RPM stall converter, headers, 10:1+ compression ratio and 3.90+ gearing. Rough idle.

• Advertised Duration (Int/Exh): 273/279
• Duration @ .050 (Int/Exh): 243/249
• Gross Valve Lift (Int/Exh): .655/.663
• LSA/ICL: 110/106
• Valve Lash (Int/Exh): .018/.018
• RPM Range: 2600-6800
• Includes: Cam Only

Part Number: 40110732
Previous Part Number: 60232
$1010 for cam, springs, lifters and timing chain.

I think you're on the right track with this one... may need to adjust gearing in the future tho... Is your trans a wide or close ratio?

[SuperBuickGuy]

It's a wider ratio. It's not the largest spread, though.

[Huskinhano]

Last year when I put a put a GT40P into my 66 Mustang I was thinking of doing a cam. I called Howard's up a couple time and talked with someone that actually knew what they were talking about and not reading from a scripted flow chart.

I think if I buy a cam, it's going to be a custom ground and not OTS.

[SuperBuickGuy]

I think when you're doing something non-traditional or in a highly-competitive class, custom ground is the best way. My 455, now 430, Buick with twin turbos - yes, to the best of my knowledge no one has done this particular combination in the particular application (I know, right, everyone should).... but for a 427 in a Corvette? I'm not smarter or more experienced then the best guys out there so an off-the-shelf grind is fine. That said, most of these cams are special order and are ground once you pay them.

[fatguyzinc]

most of my rides end up with big block chevys,
but for almost any motor i tend to run short duration
(240-250 @ .050 or so) with high lift
(.550-good, .570 better, .598, now were talking...)
and short LC. (110 is ok, i prefer 108 or less.)

i also run flat tappet hydraulics for cost & reliability
as well as driveability. i know,i know-- im a dinosaur.
deal with it.

[SuperBuickGuy]

dagnabit. the more I look at it, the more likely I'm going to put a dreaded hydraulic roller in this thing. I feel so geriatric

[fatguyzinc]

dagnabit. the more I look at it, the more likely I'm going to put a dreaded hydraulic roller in this thing. I feel so geriatric

geriatric? well, theoretically at several million years old, so is this guy...
but he is still fearsome, awesome, and would scare the crepe outta
most people if they rolled up next to him at a stoplight.....

see where im going with this?

[cstmwgn]

dagnabit. the more I look at it, the more likely I'm going to put a dreaded hydraulic roller in this thing. I feel so geriatric

Arron

I don't mean to "school" you on this so PLEASE don't take offense if all of this is "old news".
I have been running pretty stout roller cams on the street now for a few years. Again, my experience is with Fords so I am not sure the same issue I have you will have. Right now running a cam very similar to what you mentioned earlier - 261/268 @ .050 with .700ish net lift using springs that are 240 on the seat and 600 over the nose - I would not expect you to gel long life out of either your lifters or springs. My experience is that the springs start to go soft (not break but loose 15% - 20% of installed tension) somewhere between 12,000 and 15,000 miles. The lifters are the real issue to me (and often cause the most catastrophic damage). I have never gotten more than ~6,000 miles out of a set of roller lifters (Crower HIPO or Morel). In MY opinion, the issue with a hydraulic roller is that you won't know that the lifter is starting to wear (lash increasing) until the instant the lifter fails. At that point you will have lots of metal in your engine. I try to run the lash every 1,000 miles and carry a "kit" in the glovebox so I can do it in the motel parking lot while traveling (PowerTour or other long distance events). You might be surprised at how much power you can make with a flat tappet and most likely more than the traction you have can handle. They have EDM lifters now and cam break in services which go a long way in removing some of the risks associated with flat tappet cams.

Again, I hope I haven't offended you while sharing my experience in this area.

[anotheridiot]

You need to trust the power band of the cam and stick within it. We started with the performer power package, 2098. Lifters kept sticking so we swapped lifters, which of course kills a cam. We took what looked like a step down with comp, but power range went from 1500 with the edelbrock to 2600 start with the comp bump stick, even though the lift was smaller, duration was shorter, overlap the same. Nothing but eye burning rich fuel smell at idle no matter what we try to adjust. Ended up swapping converters as well and still get 4 mpg with fuel injection.

Be real honest with what you want to do with the car, and build it to those driving conditions. Its awesome to have a car cackle and rumble on unleaded fuel, but if you are not going to race the car, its probably better to get a cam closer to the specs that the motor was built with, which is probably .100 less lift and a ton less duration.