[screamingchief]

Originally Posted by goatman65

On the chassis dyno my engine peaked at 4900 rpm,397rwhp,then nosedived.

397 @ 4900.Don't remember the tq off hand but it was less than 500.I was expecting more from this size engine and cam.And more rpm.Not much of a power curve either,more like straight up then back down.

Exactly what valve springs are you using on those 6X heads?

What pushrods??

Stud girdle???

The 290b6 should pull strong to 6000+ no problemo.

Also,was that cam degreed when it was installed?

With the 6X heads and the compression your running,you really dont wanna go any bigger than that 290b6 cam.

Also,what sorta exhaust are you running,tight LSA cams absolutely abhor restrictive exhaust tracts,a restrictive exhaust system can cost big chunks of power with the tight LSA cams.

Can be lots of reasons for what your seeing,just gotta work thru the usual suspects in a logical way to eliminate any & all possible issues,it's a process,and it can be tedious at times,but you gotta expect to put in some work to reap the gains.

As for a SR cam to replicate the 290b6 when you upgrade the heads,here's my choice:

Brand & part no.:Comp custom high tech .420" SR lobes #51-000-5
Grind & lobe no.: AKA: the 290b6 roller "clone" cam. ( lobe # 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 =
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°

Compare that to the 290b6:

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°

Does'nt get any better/closer than that!

What's the diffence you ask???

Look at the additional lobe lift and the .200" duration numbers and you'll see.

And that SR cam will absolutely love better flowing heads!!!

But I'd definitely work with the current combo some more before making that leap.

Sooner or later though,those trips wont be able to keep up.

Bret P.