[72blackbird]

I finally got my 325 cfm e-heads from SD Performance, so now it's time to get the valvetrain. I told Dave I want to run the Road Paver, and he set the heads up to run this cam. I have a 73 455 2-bolt w/ARP main studs, flattop Probes, 4340 A-beams- planning to run SD's matching T-II and some 950 DP. Exhaust for now will be Hooker Super Comps and a 3" ×-pipe system. The rest of the drivetrain will be a built 200R-4 w/3000 rpm stall converter and 3.42 gears. All of this is going into my 72 Esprit.

If you have a similar combo, I'd love to hear about it. I'm mainly curious about midrange response, idle quality, acceleration, etc. Thanks for your replies.

Geno

[Chicagogoat]

I have a very similar combo, cnc ported 325 chm @.700 lift KRE D's, port matched Victor, Pro Systems 1000 cfm 4150, 10" 3000 stall nitrous converter, TH400, 3.55 gears, Doug's headers, 3" full duals w/X-pipe. I'm running the Voodoo 705 cam with 1.65 HS rockers and original Rhoads. It idles smooth and steady and is pretty good all around with excellent throttle response. Although if money was no issue I'd go with the road paver as well in a heartbeat, it seems to be the go to cam with these ported alum heads with over 10.5:1 compression. I did notice the posted lift #'s on the SD site say .608" with 1.52 rockers, so that may shoot lift #'s past what some of us can run without changing to longer valves or switching back to 1.5 rockers. Can Dave order these same cams with shorter or longer lifts when necessary?

[blykins]

Power brakes? Where would you like the peak hp rpm to be?

[Cliff R]

What is the compression ratio of the engine?

Big player in cam choice here......Cliff

[72blackbird]

My 455 has a 4.171" bore, piston - deck is .0015", chambers volume at 85-86cc- I'd say the SCR is 10.4:1. The car currently has stock rotors and single piston calipers (rear off a 79 WS6 TA), and the matching brake booster and master cylinder. Obviously with a big hp upgrade I'm planning to go to much bigger brakes- most likely Wilwood 14" rotors and 6 piston calipers up front, 13" rotors and 4 piston calpiers in back- hydro boost is planned as well.

Geno

[chuckies76ta]

I'm running mostly the same in both cars, except were running KRE heads. My wife has run a best of 10.91 with her car so far. Also has 3.42 gears, TH400. I'm running a hydro boost. Stopping is no problem. My Wife's car is still running a stock setup and the braking has always been really good on that car.

[Cliff R]

With a true 10.4 to 1 compression and 325cfm head flow I'd look at the larger cam.

I've built quit a few 455's with 290-330cfm aluminum heads at this point and have used either the OF or RP cam. The SP starts to become a better choice if you are at or just below 10 to 1 compression due to the OF on a 112LA starting to get a little "soggy" at idle.

The OF still works OK down around 10 to 1, but it works a LOT better with more compression. My engine is 11 to 1 with 290cfm head flow and it's a home-run in that application. 13.5" vacuum at 750rpm's with 10 degrees timing, excellent street manners and runs well at the track. The tach rips right past 6000rpms and it's still pulling hard to 6400rpm's or so, but it's probably on the downslide past about 5800rpm's. I also have the ICL at 109.5 not 108........Cliff

[Chicagogoat]

The largest cam in the Voodoo HR line is comparable to the very popular SD RP cam but with less lift and it's listed with 110 LSA, whereas on the SD site states LSA either 112 or 114. Here they are in a side by side comparison. I assume the RP can be ordered with less lift and the VD can also be tweaked with a different LSA at an increased cost.

Road Paver Lunati #713
Dur @.050 246/252 243/251
Lift .608/.608 .560/.565
LSA 112 or 114 110
Cost $379 $335

http://www.sdperformance.com/listPro...p?categoryID=2

https://www.lunatipower.com/Product....d=3211&gid=289

[blykins]

Long lobe centers are not needed unless the cam designer is trying to cut down the overlap after using long advertised durations.

I would recommend a custom Comp stick...243/249 at .050, 110 LSA, 104 ICL, .575/.550 with 1.65 rocker. Little cheaper than the Road Paver.

Take advantage of the shorter LSA, it will add torque, throttle response, lower rpm manners, and will sound better.

BTW, never pay attention to the description under the cam specs. How do they know if you are putting it in a 350 or a 535? The description is never valid unless you give them every spec of your combo.

[72blackbird]

I posted this thread because I've never built a 455 this aggressive before- my last 455 had ported no.64s, a Crower 60919, 850 DP on a T-II, but it also had TRWs and cast rods w/ ARP bolts, so I rarely revved it past 5500 rpm, let alone 5200. This 455 has a better bottom end, so I won't hesitate to take it to 6000, or even a little over that if needed. It obviously has much better heads too, so I'm thinking it's going to breathe deeper than my old 455 too.

I'm also curious how a 110 LSA vs. a 112 LSA could make such a big difference in characteristics, if both cams otherwise had the same specs and had long duration. Wouldnt a tighter LSA increase overlap and decrease torque? Since I'm planning to use the 455 in my Bird on road courses, all out power isn't as important as off throttle to midrange response, like when coming off a corner, or going through a section of curves. But naturally all out power is also important on a straightaway, so I'm leaning towards a larger cam like the RP over the OF.

Geno

[blykins]

A tighter LSA makes torque. Also, when you tighten the LSA up, the ICL usually goes with it, and advanced cam timing really helps on throttle response and low rpm operation, like if you're autocrossing or road racing and need that quick reaction coming out of a turn.

In most cases a tighter LSA will increase overlap, but it really depends on the lobe design itself. For instance, you could have a 215/218 @ .050" hydraulic flat tappet camshaft, on a 106 LSA and have enough vacuum to operate power brakes. It's all relative.

I try to design cams taking everything into consideration as all of the off-the-shelf camshafts, whether it be from SD, Crower, Lunati, Comp, etc., will be a little more universal than something specific.

You will love the 455 with the modifications you have made. It will be a kick in the pants.

[TCSGTO]

Originally Posted by blykins

A tighter LSA makes torque. Also, when you tighten the LSA up, the ICL usually goes with it, and advanced cam timing really helps on throttle response and low rpm operation, like if you're autocrossing or road racing and need that quick reaction coming out of a turn.

In most cases a tighter LSA will increase overlap, but it really depends on the lobe design itself. For instance, you could have a 215/218 @ .050" hydraulic flat tappet camshaft, on a 106 LSA and have enough vacuum to operate power brakes. It's all relative.

I try to design cams taking everything into consideration as all of the off-the-shelf camshafts, whether it be from SD, Crower, Lunati, Comp, etc., will be a little more universal than something specific.

You will love the 455 with the modifications you have made. It will be a kick in the pants.

I wouldn't lump SD in with the other " shelf" cams. He has many other profiles other than the common ones listed. I doubt Dave will come on here but maybe he'll chime in on his extensive dyno experiences with long stroke Pontiacs and how wider LSA's often run quicker than tighter profiles.

[ta man]

The only thing that concerns me is 3.42 gearing and a 200r4 transmission.The engine won't like to run at normal constant highway speed at a low rpm..For the intended use of the OP this should be ok.Hopefully that 200r4 is built with a good quality lockup convertor.

[blykins]

I wasn't trying to negatively spin anyone's product, but the point was no single camshaft will span across two hand-fulls of engines.

I've also found the longer LSA cams function well with bigger inch engines, but we're talking 500+ cubic inches. The bigger displacements pull so hard on the head that they don't need any help with exhaust scavenging.

Lots of these off-the-shelf cams have a lot of added exhaust duration to make the engine sound good or to try and help with a poor exhaust flow problem, and then the LSA is widened to try to gain some vacuum back, so the guys with the power brakes don't fuss.

[Steve C.]

"Built 200R-4 w/3000 rpm stall converter and 3.42 gears. All of this is going into my 72 Esprit."

"I'm planning to use the 455 in my Bird on road courses, all out power isn't as important as off throttle to midrange response, like when coming off a corner, or going through a section of curves. But naturally all out power is also important on a straightaway, so I'm leaning towards a larger cam like the RP over the OF."

Shifting the 200R-4 transmission ? Lock up or non lock up converter ?


For conversation not a recommendation.....

UltraDyne HR 19 hydraulic roller lobe / intake
300 degrees seat duration
245 at .050
169 at .200
.3823 lobe lift (.630" 3/1.65 ratio)

More aggressive at 0.200 duration than the Road Paver. Great valve lift with a higher rocker ratio. Road Paver Comp lobe 3115B has .4000" lobe lift )

UltraDyne HR20 lobe / exhaust
304 degrees seat duration
249 at at .050
174 at .2000
.3823" lobe lift

Presume the ported Edelbrock heads will have a very good exhaust port and thus cylinder heads that will have a good exhaust-to-intake flow ratio. This lobe will provide less split between the intake and exhaust regarding duration.

Bullet Racing will custom grind it in whatever lobe separation desired.


.

[Cliff R]

Tight LSA cams in 455's narrow up the power curve and make high peak torque numbers, all else being equal.

A 455 by design is going to make a BUTT LOAD of torque, simply because it's a huge engine. When we get them up from the dismally low compression ratios most came with, they gobble up a relatively big cam and idle well with good street manners.

Even the big "Road Paver" cam from Dave at SD idles like a kitten in a 455 with 10.5 or higher compression with "normal" timing in it.

Tight LSA cams overall work poorly in 455 builds until you pick one big enough where the off-seat timing is great enough that it raises peak HP high enough the narrower power curve doesn't have it quitting to early in the rpm range.

The absolute WORST cam you will ever put in a 455 street engine build with any decent compression will be a "small" cam on a tight LSA.

Even bigger cams on tight LSA's often don't make the grade. Case in point. A few years back we built a 455 with #48 heads and installed a 308/314, 246/254 cam on a 108LSA. To date I don't think we've built a 455 with a power curve that explosive. It idled with great authority, TONS of low end power, and would tear your head slam off in the mid-range. That engine felt like it was going to run well into the 10's if you evaluated it by the "seat of your pants". Remarkably, the car ran the very best of 12.20 @ 112mph with traction. Hmm?

We replaced the cam with the Road Paver from Dave at SD, which is close in specs but 112LSA. At the same time we installed a set of his ported #62 heads, short block was untouched. The new combo idled nearly smooth, with a deep/heavy sound and barely any noticeable lope. It was no longer raspy, nor did it have the explosive power of the first set-up. Instead, power was very smooth and linear, is just pulled hard clear across the load/speed range. It really didn't "feel" like it was going to run much into the 12's if evaluated by the "seat of your" pants, the power curve was just too smooth and somewhat boring.

Track day came and the car blasted off mid 11 second runs over 116mph with a best run in the 11.30's at 118mph!!!!!!!!!

Something to be said there for a big cam on a wide LSA in one of those engines.

While on the subject I'll also put these dyno sheets up here again, comparing a smaller tight LSA cam in a 9.5 to 1 compression 455 engine build with a larger cam on a wider LSA. The dyno charts clearly show what happens when you don't put enough cam in the 455, even at a relatively "low" compression ratio.

I'll also mention here that a few years ago we built a known combination, 455, a little over 10 to 1 compression, 290cfm KRE aluminum "D" ports from Dave at SD, and custom Comp flat solid cam around 244/252 on a 110LSA. All of the engines we've done prior to this one used the OF cam and made over 550hp and 600tq. With the solid cam on a tighter LSA the best numbers we could get out of it with all the stops pulled out are below on the second dyno chart. The cam specs are also shown although just a tad out of focus............Cliff

[Steve C.]

Where is the torque peak with the longer duration cams ?

For a 'road race' conversation...

"What would be better on the race track if the two engines in question, both had the same HP but one had more torque than the other. " The one with more torque, torque adds drivability to an engine. That's an easy question to answer. But what if the question was "What would be better on the race track a turbo 4 cylindert 500HP with 200 (avg) torque, or someithing like a v8 with 450HP and 350 (avg) torque (these are figures I just plucked out of the air)" The answer would depend on, whats the track, whats the gearing of both cars, how good is the driver etc etc etc. In this case its not as simple as the first, as the car with more torque would accelerate harder in any given gear lower down, but has less ultimate grunt, the engine would feel 'torquey'. Its also important to remember that the higher torque gives an 80% max power reading across a wider rev range, increasing drivability. With the other engine, all the power and acceleration comes at he top end. However this isnt as bad as it seems for acceleration as some of this low down loss can be eliminated with clever selection of gears. So what would you want here. If the track had long open straights, and relatively few slow corner to fast straight, you'd be better with the HP of the turbo 4pot. If the track had lots of slow corners mid length straights you'd want the extra torque of the v8 for initial acceleration.

Reference https://www.physicsforums.com/thread...r-many.301773/


.

[pastry_chef]

The Road Paver is s fine start.

I see from the SD website:

2.19” intake valves, 1.77” exhaust valves.

Intake flow:
265cfm @ .400" lift
295cfm @ .500" lift
320-325cfm @ .600” lift

Are these numbers close to your sheet?

Can you provide the exhaust flows at .400, .500 and .600 please?

I would target peak HP at 6200 RPM.
I'm going to guess the ideal cam will be larger than the road paver by a bit.

What rocker ratio will you run?

[TCSGTO]

Originally Posted by blykins

I wasn't trying to negatively spin anyone's product, but the point was no single camshaft will span across two hand-fulls of engines.

I've also found the longer LSA cams function well with bigger inch engines, but we're talking 500+ cubic inches. The bigger displacements pull so hard on the head that they don't need any help with exhaust scavenging.

Lots of these off-the-shelf cams have a lot of added exhaust duration to make the engine sound good or to try and help with a poor exhaust flow problem, and then the LSA is widened to try to gain some vacuum back, so the guys with the power brakes don't fuss.

I appologise if my post sounded like I was implying you were bashing SD or anyone else, that wasn't my intention. Just pointing out they offer much more than what's listed. Actually I'm talking to Dave now about a cam change a wanted to order the RP but hes recommending something totally different.

[pastry_chef]

Assuming 240 cfm @ .500 lift exhaust flow
1.5 ratio rocker.

Well, mild it isn't
It would push the car into the 10's with proper setup.

Comp Cams QXX Hyd Roller
--------------------------

Intake Lobe 13488

313 adv

259 @ 050

.389 lobe lift

---------------------
Exhaust Lobe 13491

319 adv

265 @.050

.389 lobe lift
----------------------

108 LSA.
Install at 103 intake center-line