[1funride]

There are a bunch of manufactures that make 041 like cams, at least 4 and a bunch others have in the past. They all seem to net the same results (modeled) with "very" little difference. I guess that makes sense since they are actually very close or exact copies with a little more lift. I seen a post by UD Harold that indicated that the UD and Vodoo cams were not the same. He indicated that the overall advertised duration and lift was dictated by Lunati, but the lobe was of his design.

I have wondered if that meant the Lunati cam was an improvement in his mind, or was he held to more design constraints at Lunati, which forced him to ramp the lobe up quicker? Was the UD cam a better design with less constraints?

In any event, all seem to fall in the same range of performance as other 041 like cams. The question could be, which is better from the aspect of less valve train wear and tear, idle vacuum, and driveability?

[Steve C.]

At one time I assumed all or most of the UltraDyne lobes were the same as the Voodoo lobes. Then Paul Carter corrected me within a post here at PY. That was much appreciated and with his explanations as to why they were not. A better design by Harold while at Lunati. I enjoy reading, and trust Paul's comments regarding the Voodoo lobes with his experiance using them, and his association with Harold Brrokshire. Seek out his posts on the topic. Or contact him direct.

That said, like many here I purchased UltraDyne cams from Harold when he owned and operated the origional company, and while he was at Lunati. Then later from Bullet Racing. Still a fan of UltraDyne cams

Keep in mind a engine will respond to additionl valve lift.

Paul Carter
Carter Cryogenics
www.cartercryo.com
520-409-7236
Koerner Racing Engines
520-294-5758


.

[bullheimer]

Can anybody give me a link to a thread on this same topic (lots of Ultradyne cam experiences) with a 400 engine? in particular, iron heads with a c.r. in the 9:1 range? if so, thx.!

[1968GTO421]

Subscribed!

[HWYSTR455]

Originally Posted by hurryinhoosier62

Closed lop or open loop? MOST factory EFI systems with closed loop can't "keep up" with a tight LSA. Most cam manufacturers advise you to stay with a loose LSA IF you're running an OEM closed loop system. I could be wrong, but I believe most aftermarket EFI systems recommend an LSA of 112-116 degrees as well.

I believe that is a correct statement, that most aftermarket EFI suppliers do recommend a 112-116 LSA.

There are some caveats to that though, for example, throttle body injection as compared to multiport. Mutliport systems are more sensitive to LSA, or at least that's what I've seen/heard.

I have also seen/heard folks having issues with throttle body injection systems when the LSAs get into the 106-108 range, to a point where some either ditch the system or change the cam. In those cases closed loop is ineffective, and many statically map the fuel curve. When you think about it, you're pitching one of the basic reasons most even switch to EFI.

.

[JLMounce]

Originally Posted by HWYSTR455

I believe that is a correct statement, that most aftermarket EFI suppliers do recommend a 112-116 LSA.

There are some caveats to that though, for example, throttle body injection as compared to multiport. Mutliport systems are more sensitive to LSA, or at least that's what I've seen/heard.

I have also seen/heard folks having issues with throttle body injection systems when the LSAs get into the 106-108 range, to a point where some either ditch the system or change the cam. In those cases closed loop is ineffective, and many statically map the fuel curve. When you think about it, you're pitching one of the basic reasons most even switch to EFI.

.

It's not entirely that a closed loop system can't keep up with a tight LSA cam, it's more to the point that the tuning is hard to undertake. Closed loop system rely heavily on data tables that are manually created. It's far easier to tune these tables when the engine is acting in a more linear and even fashion. Narrowing the LSA narrows the power band, which makes the tuning more difficult.

THe OEM's obviously have teams of people devoted to this, where joe-bob down the street does not. It adds considerable additional expense to have the car tuned by a professional that knows what he's doing. Depending on what needs done you could be adding $400-$1000 fairly easily.

With the newer systems on the market that employ wideband sensors and operate primarily in an open loop fashion, it's become less of an issue.

I pulled a 280H that has a 110 LSA and made about 8" Hg from my 462. The FiTech system I'm running didn't care that it had a LSA on the tighter side and didn't make crap for vacuum.

[Bob70Goat]

now I'm REALLY confused.. 1970 455, # 64 mildporting , currently have a RAIV copy , wanting to make more low end power, better vac,, better economy and less fumes - was considering a 068 copy but with so much information and dis information .. who knows now

[tom s]

IMO a 068 is too small for a 455.Tom

[Bob70Goat]

what would you suggest then ,, I'm open to all suggestions .. my biggest fear is raising cylinder press too much and causing detonation .. none as of yet I use pump 93 .. want good vacumn , good sound and great low end torque and power .. not asking for much am I?

[ponyakr]

It's been my experience that all you need with a RA4 copy is Rhoads lifters. That's what I ran in most of our 455 bracket cars. Launched from an 800rpm footbrake idle, with a stock 13" converter, and ran 60ft times in the 1.60's.

BUT, given what you say you want, an 068 clone may be all you need. That's the cam that was used in that engine, with a manual trans. The auto trans engines used an 067 cam. Even the 455HO engines only used the 068.

http://www.wallaceracing.com/enginesearch4.htm

But, if you go this route, you might as well at least go with a Summit 2801. It's sort of a higher lift version of an 068.

https://www.summitracing.com/parts/sum-2801



"...good sound and great low end torque and power..."

Since you added the words "good sound", I'd say that eliminates an 068. The idle will be dead smooth, in a 455.

I'd say the next step below the RA4 clone might be a Crower 60243. I've seen it recommended mostly for 400's. But, it might work for what you want.

https://www.summitracing.com/parts/cro-60243

Below that might be the Summit 2802 & RA3 (744) clone.

https://www.summitracing.com/parts/sum-2802

The 744 clones have only about .407 lift, which will leave a lot on the table, as they say.

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

Between the 2801 & 2802, are the Crower 60242 & 60916.

http://www.cnc-motorsports.com/crowe...-camshaft.html

https://www.summitracing.com/parts/cro-60916

This Crane might fall somewhere in the middle of the pack.

https://www.summitracing.com/parts/crn-283951

This Lunati version of a 744 cam, might work. With 301/313 adv dur, it should bleed off a little compression, which might help avoid detonation. The SD455 engine came with a 744 spec grind.

https://www.summitracing.com/parts/lun-10511004

[Bob70Goat]

thanks I currently have a ra4 copy , rhoades lifterts as well .. love the sound but as you know does really devolp power until the upper rpms, and for a weekend cruiser that occasionally gets romped on .. converter is a 2600 ( if I recall ) which may be part of problem but will be going 2004r , have 373 in rear

[pastry_chef]

Originally Posted by Bob70Goat

thanks I currently have a ra4 copy , rhoades lifterts as well .. love the sound but as you know does really devolp power until the upper rpms, and for a weekend cruiser that occasionally gets romped on .. converter is a 2600 ( if I recall ) which may be part of problem but will be going 2004r , have 373 in rear

Static compression?

Maybe something like Lunati Voodoo 10510703


Hydraulic Flat Tappet Cam. High performance street/strip cam for 350 c.i. motors. Excellent cam for 400- 455 c.i. touring type vehicles with 9:1-9:5 compression ratio. Use 2200-2400 RPM stall converter with 3.23-3.42 rear gears. Very noticeable idle quality.

Advertised Duration (Int/Exh): 268/276
Duration @ .050 (Int/Exh): 227/233
Gross Valve Lift (Int/Exh): .489/.504
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1600-5800

http://www.lunatipower.com/Product.aspx?id=1776&gid=287

[ponyakr]

Unless that engine has dish pistons, wouldn't that Voodoo cam tend to increase the possibility of detonation ?

With flat top pistons, those engines are listed at 10.25 CR.

http://www.wallaceracing.com/enginesearch4.htm


"...ra4 copy , rhoades lifterts as well .. love the sound but as you know does really devolp power until the upper rpms..."

That has not been my experience at all. In my 455 bracket engines, the power range was from idle to 5000rpm, although they would go to 5500. I'd estimate the hp at 400 @ 5000 rpm, and the torque at 500 @ about 3000 rpm. But, I had the 72cc heads on most of those engines. Don't know if the extra compression made any difference or not. I don't think so, because my 1st 455 came out of a 70 GTO. It was the original engine, so it had the #64 heads. The only change I made was the RA4 clone/Rhoads swap. In a '68 Bird, with a TH400, 13" stock converter, & 3.55 gears, it ran easy 12.40's & 50's, launching from an idle, & shifting at 5000.

[scott70]

Originally Posted by Bob70Goat

thanks I currently have a ra4 copy , rhoades lifterts as well .. love the sound but as you know does really devolp power until the upper rpms, and for a weekend cruiser that occasionally gets romped on .. converter is a 2600 ( if I recall ) which may be part of problem but will be going 2004r , have 373 in rear

I run the same motor in my 70 gto,,455,,#64 ported by SD,,stock intake and ram air manifolds. Crower 60919,,(very close to RA4 cam ) with rhoads v max. 3.31 with 4 speed. All the low end you can use. Cant keep the tires hooked up even going WOT from idle....1st or 2nd gear. With 3.73 gears,rhoads and your auto the low end should be ridiculous.

[ponyakr]

Maybe there is an ignition and/or carb tuning problem. There are just too many guys who have run the 455 / 041 cam / Rhoads lifters combo, who have experience LOTS of low end torque, plenty of vac, and a good idle.

So, I have to suspect ignition or carb problems, rather than having a cam that is too big.

Probably be a good idea to set the ignition curve for the total mechanical advance to come in by no later than 3000 rpm. Some recommend 2500. Most(but not all) iron head Pontiacs seem to like between 34 & 36 degrees total mechanical advance. You can buy advance spring kits, with 3 sets of springs. Most say the weakest springs in the lits should not be used. But some combination of stock and/or 1 or more springs from the kit, will set your curve where it should be. MSD sells a kit. Crane has a kit for either HEI or points type dist, with adjustable vac adv included. And there are several cheaper kits, which all probably contain the same Chinese parts.

https://www.summitracing.com/parts/msd-8428/overview/

https://www.summitracing.com/parts/c...qDAaAkgw8P8HAQ

https://www.summitracing.com/search/...0weight%20kits

https://www.summitracing.com/parts/mrg-929g/overview/

https://www.summitracing.com/parts/pro-66948c/overview/

https://www.summitracing.com/parts/a...1300/overview/

https://www.summitracing.com/parts/trd-4933/overview/

https://www.summitracing.com/parts/sum-g5212/overview/

http://www.jegs.com/pt/Distributor+A...Kit/4294946058

When you set the total to the best for your engine, you may(or may not) need to limit the amount the advance weights can advance the timing. Let's say your optimum total is 34 degrees. If, at this setting, your initial timing is at say, only 10 degrees, at idle, you need to limit the advance weight mechanism, with a positive stop, so that you can increase your initial advance, for improved off idle power. There are different ways to do this, with different types of dist. With a stock HEI, it can be done with a screw in one of the extra holes in the bar, which the rotor attaches to. I recently did mine with a metric allen head screw, with the head under the bar.

There are a couple of pics & a mention of this mod, near the bottom of the page, at this link.

http://www.crankshaftcoalition.com/w...EI_distributor

[AdamIsAdam]

This is a great thread and I just re-read the ENTIRE thing! (ouch!) So I'm bumping it up for those who have never seen it.

I'll ask my question of Cliff publicly so maybe others can benefit from it...

Cliff,
When I was considering a cam change a while back you were nice enough to make a suggestion. I have been doing other mods since then including finally installing my 1/2" fuel delivery (RobbMc) this week. Dyno session coming soon...

Anyway, my question is this:

How do you think the Ultradyne 288/296, 231/239 @ .050” cam on a 112LSA instead of 110. (Leave it on a 110 if you want a “choppy” idle and less vacuum at idle speed) or the Crower 60919 cam with the ICL at 109 and Rhoad’s lifters compares to the 041 with Rhoad's lifters?


For those who don't know, I've got a XE274 cam in my 469 stroker. Details are:

WAS A 400
o Bored and stroked to 469ci (4.19 x 4.25)
o Eagle crank
o “H” beam, rods
o Ross Pistons
o Fully balanced by Butler Performance
o 10.13 CR


o Cam: CompCam XE274H-10
 Adv Dur: 274 Int; 286 Exh
 Lobe Sep: 110
 Lift: 488 Int; 491 Exh (Net: 536 Int; 540 Exh with 1.65 rockers)

o Heads: #46 with screw in studs, 75cc chamber (Rebuilt May 2015)
 Ferrea Valves (Int: 2.11; Exh: 1.77)
 255 cfm at 527 lift
 1.65 roller rockers by Harland Sharp
 Comp Cams double springs
 Ported and polished
 Port matched to intake
 Screw in studs
 Crossover filled
 ARP Head Bolts

o Edelbrock Prototype P4B-Q4 Extensively Ported by SD with Cliff Ruggles
o Cliff Ruggles Custom Q-Jet
o MSD 6AL electronic ignition

• Clutch, Transmission, Rear
o McLeod Racing Clutch 75221-Super Street Pro
o Lakewood scatter shield
o Muncie M21 fully custom rebuild with hardened gears
o Hurst Competition Plus shifter
o Dual drive shaft safety loops
o Eaton Posi Unit, Timken Bearings
o 3.42 Motive Gears

[Cliff R]

The Crower 60919 and RAIV cam as basically the same thing, so expect the same results with either one. They work fine without the Rhoads lifters, ran my old 455 w/o them for quite a while. When I finally added Rhoads lifters to the cam vacuum at idle increased 2" and it also improved throttle response right off idle.....Cliff

[STEELCITYFIREBIRD]

If I recall correctly you have a 1975 557 block, correct?
This is like a case study of how a 557 will hold up with a longer stroke and some hard runs, with traction.

[Cliff R]

To date everyone I've seen that built a 455 with one of those blocks over about 450hp has had troubles with them.......FWIW.....

[steve25]

Let's look at things in the way that the factory engineers did in regards to the strength of engine parts, that being that whenever possible they wanted a 2 to 1 strength ratio.

In light of this and there prove out test of 24 hours at 4500 rpm I propose this.

The last 400 cid motor topped out at 220 hp with that 557 block, if doubled the hp output to 440 the engineers would have told you your playing with Fire even at only 4500 rpm, now lets up the rpm to 5500 and you have now doubled the load on the main web of that 557 block, now if you add near another 1/4" of stroke over the 400 motors 3.750" your really asking for it and it's just a matter of time and how good your tune is!