[goatman65]

Will this combo support a RoadPaver cam or would OF be a better choice?
467
10.3 comp
KRE D ports 280 cfm, set up for solid flat tappet
Tri power ported/gasket matched to heads, carbs opened to 500 cfm
I have HS rollers in both 1.5 and 1.65 I can use
Dougs 1 3/4 headers full exhaust 2 1/2
4 speed m22 3.90 rear

The cam I have been running,
Comp 290b6 solid flat tappet
290-304 adv
256-267@050
362-358 lobe lift
594-587 valve lift with 1.65, actually 597-590,cam card is wrong.
106 lsa

I like the cam I have now just looking for something that might be better suited to my combo. Maybe something stronger 3000 rpm up. I have more than enough low end.

[surfsama]

I vote the RoadPaver but if I had your mill, I would talk with experienced Pontiac engine builders about a custom grind.

[i82much]

Close ratio, seems tailor-made for a tight lobe sep to me.

[Steve C.]

Specs on the 290b to help in apples-to-apples comparisions.....


Brand & part no.: Comp Cams Part no.51-659-5 . (catalog grind)
Grind & lobe no.: Grind no.290b6 (lobe #6061/#6013)
Tappet type: Solid Flat Tappet
Spec = intake/exhaust: (notes)
Adv.Duration = 290°/304° (I/E split 14°) (note: rated @ .020")
Dur. @ .050" = 255°/266° (I/E split 11°)
Dur. @ .200" = 160°/172° (I/E split 12°)
Lobe lift = .360"/.356"
Lift @ 1.5 rr = .540"/.534" (Gross lift) (For Net lift subtract lash)
Lash = .026"/.028"
LSA = 106° ICL = 106° ECL = 106°

Seat events:
IO = 39° BTDC
IC = 71° ABDC
EO = 78° BBDC
EC = 46° ATDC
Total O/L = 85°

.050" events:
IO = 21.5° BTDC
IC = 53.5° ABDC
EO = 59° BBDC
EC = 27° ATDC
O/L @ .050" = 48.5°

[Steve C.]

More numbers from Bret Peterson...

I came up with this solid roller version of the 290b6 cam a while back when someone here asked a very similar question.

Grind & lobe no.: AKA: the 290b6 roller "clone" cam.
( Hi-Tec .420 lobes # 4009/4023)
Tappet type: Solid Roller Tappet
Spec = intake/exhaust: (notes)
Adv.duration = 290°/304° (I/E split = 14°) (note: rated @ .020")
Dur. @ .050" = 254°/266° (I/E split = 12°)
Dur. @ .200" = 171°/180° (I/E split = 9°)
Lobe lift = .420"
Lift @ 1.5 rr = .630"/.630" (Gross lift) (To get Net lift subtract lash below)
Lash = .022"/.024"
106° LSA = 106° ICL = 106° ECL

Seat events:
IO = 39° BTDC
IC = 71° ABDC
EO = 78° BBDC
EC = 46° ATDC
OL = 85°

Events @ .050":
IO = 21° BTDC
IC = 53° ABDC
EO = 59° BBDC
EC = 27° ATDC
OL = 48°

This SR cam would be very comparable to the SD racing road paver HR cam in many respects.

Though it is on a tigher LSA so that would pull the peaks (hp/trq) down ever so slightly,and it can easily be installed on a 100° or 104° ICL to help there even more.

Duration @ .020" is under 200° so a lifter bore brace is'nt mandatory,and the HighTec .420 lobes are pretty mellow lobes,so super crazy spring pressures should'nt be needed and it should be pretty easy on the valvetrain.

Being a roller,it wont idle as "snotty" as the flat tappet 290b6 would,but by no means does that mean it's going to sound "tame" either.

Also,the SR version of the 290b6 cam has more duration @ .200" than the SFT version has,so this cam almost certainly would make more power than the SFT 290b6 cam does.

IMO it should make very good power with the stated headflow.

And be sure to use good lifters no matter what roller cam you end up using.

FWIW

Bret P.

[Steve C.]

And the Roadpaver from Bret....

Brand & part no.: Comp cams ~ SD performance custom
Grind & lobe no.: Magnum lobes # 3115B ~ #3116B
Tappet type: Hydraulic Roller
Spec = intake/exhaust: (notes)
Adv.dur. = 306°/314° (I/E split = 8°) (Adv.dur. rated @ .006")
Dur. @ .050" = 246°/252° (I/E split = 6°)
Dur. @ .200"= 164°/169° (I/E split = 5°)
Lobe lift = .400"
Lift @ 1.5 rr. = .600"/.600"
LSA = 112° ICL = 108° ECL = 116°

Advertised/seat events:
IO = 45° BTDC
IC = 81° ABDC
EO = 93° BBDC
EC = 41° ATDC
Total OL = 86°

.050" events:
IO = 15° BTDC
IC = 51° ABDC
EO = 62° BBDC
EC = 10° ATDC
OL @ .050" = 25°


"I don't think you'd "lose" anything between the two cams,just one is HR and the other is a SR,not a huge difference mind you,IIRC the road paver HR is .400" lobes,and the SR is .420" lobes,and due to more lobe lift the SR cam will also have more duration @ .200",thus it would likely make just a little bit more power than the HR cam would make.
Also one is (advertised duration) rated @ .006" while the other is rated @ .020".
And with a little more duration @ .050" with the SR cam,that also means a bit more OL at that point as well,potentially improving exhaust scavenging."

.

[goatman65]

Thanks for all this info. The roller version 290b is very close to the roadpaver.

My heads are fairly new, maybe 300 miles on them. I don't know the spring brand or pressure,probably Comp 995. They were set up for the 290b solid so do you think the springs would be good for the 'roller' version 290b?

[Steve C.]

I'm not sure what Bret had in mind with valve springs during the discussions with those numbers. Are you asking about valvesprings for the hydraulic roller lobes or the solid roller lobes ?

I know of a recent build using the Comp Hi-Tech .420 solid roller lobes and Comp suggested 240 lbs seat pressure, if it was going to be raced and banged on Otherwise I believe he mentioned about 200-225 lbs, not sure. And recently I was considering a cam change to similar solid roller lobes from Bullet Racing Cams with the same 0.200" duration and the same 0.4200" lobe lift as the Comp Hi-Tech .420 roller lobes and Bullet recommended 225-230 lbs on the seat.


.

[Steve C.]

Valvesprings for the hydraulic roller lobes, for a general idea take a cue from post #16 here:

http://forums.maxperformanceinc.com/...d.php?t=790353

However those specific springs don't have the lift capacity for the Roadpavers .4000" lobe lift.

Your going to have to know specific information regarding your cylinder heads, example the installed height.

.

[Steve C.]

Just a fwiw, dispite what the Comp catalog suggests some will express the opinion the 995 valve springs are inadequate for the 290B solid flat tappet cam. Personaly I'd put more stock in Bullet's recommendation than the typical Comp catalog offering. But again much depends on the actual installed height and pressure involved


.