[Johnny406]

I have been collecting parts for this motor for a couple of years now and I have just about everything I need to begin assembling it for the 2013 season. This is a bracket motor, I want it to run well and consistent with or w/o the bottle.

Block: very low use 4 bolt 428 bored .010 over and honed w/torque plates by Greg Merrick. Original 4 bolt caps and hardware
Crank: Race prepped factory 428 crank
Pistons & Rods: Venolia flat top blower pistons w .990 floating pins on H-Beam rods (not sure the brand)
Heads: Butler ported RPM E-heads resprung for a flat tapped cam. Flow 305cfm at .600
Cam: Custom ground Comp hyd flat tappet based of a Chebby n2o grind. I actually had this ground for the old 406. I'll use either 1.65 Pontiac or 1.7 Ford rockers for it.

Grind Information
Intake Lobe: 5087 Exhaust Lobe: 5214
Lobe Sep.: 13 Advance: 5
Description: hyd flat tappet, dur @ .050 230 I & 244 E, valve lift .504 I & .501 exh

Intake: Northwind 4500
Carb: Shaker455 built 1050 Dominator
Ignition: Dave Ray built distributor w/ MSD 6AL
Oil System: Probably the 7qt Moroso pan and pump off the 463.

I expect to need a different converter, hopefully the 3.90's will be fine but I'll change those as well if necessary.

[71 Ventura II]

IMHO Cam seems pretty small for the CID especially for the nitrous use. Could you call Bullet or ??? and get a better match? To take advantage of the head flow you would need a minimum of .600 "Net" lift. Generally cam grinders actually use lift a little higher than the max flow to gain power. Even if you use the Harland Sharp 1.73's your still short on lift with .581/.577. Note: when you accelerate the lifter with the 1.73's you will need to account for it with the proper spring pressures, which brings the issue of flat tappet cams into play.

I'll be interested to see what others say about running a .230/.244 cam in a 430 CID with 305 cfm E-heads on the juice or off. JD

P.S. Compare your 430 CID combo to this well known 406 combo "The Dude" ran years ago! Take note of the nitrous passes! Look at the camshaft used with a 406 cid and consider where you need to be with the larger engine.
https://sites.google.com/site/ksmsin...t-engine-combo

Jim Taylor "West Coast" old 428 nitrous combo:
http://www.pontiacstreetperformance....ld428jomt.html

More info from the "Dude"!!!
http://www.angelfire.com/fl4/pontiacdude428/NOS2.html

[69Goat1]

Johnny - Don't you have a 290B6 laying around somewhere?

Comp Cams 290b6 solid:
Spec = intake/exhaust
Adv.Dur. = 290°/304°
Dur. @ .050" = 255°/266°
Dur. @ .200" = 160°/172°
Lobe lift = .360"/.356" Rec.lash = .026"/.028"
LSA = 106° ICL = 106° ECL = 106°

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

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

[Johnny406]

Originally Posted by 69Goat1

Johnny - Don't you have a 290B6 laying around somewhere?

Yes I do and to be honest, that was the cam I was planning to use when I had the heads re-sprung. I just didn't think it would like the spray so much with the tight LSA.

I was also thinking on using the XE294 I had in the 463 prior to going to the solid Ultradyne.

[Johnny406]

Thank you so much for your post 71 Ventura II, alot of good info there and I will revisit the cam selection. I just thought that cam would be a good choice since it was on hand and was ground for spray. Though you're right, it was for a lower RPM iron headed engine.

[69Goat1]

Originally Posted by Johnny406

Yes I do and to be honest, that was the cam I was planning to use when I had the heads re-sprung. I just didn't think it would like the spray so much with the tight LSA.

I was also thinking on using the XE294 I had in the 463 prior to going to the solid Ultradyne.

I guess I am trying to figure out where "NOS" and "Bracket Motor" should even be used in the same sentence? Going rounds and switching bottles, bleeding pressure, heating bottles, etc...

I have used the 290B6... GREAT torque cam!

[Johnny406]

Originally Posted by 69Goat1

I guess I am trying to figure out where "NOS" and "Bracket Motor" should even be used in the same sentence? Going rounds and switching bottles, bleeding pressure, heating bottles, etc...

I have used the 290B6... GREAT torque cam!

Fair question, the NOS was more for fun like time only and fun grudge racing but on motor for dial in bracket racing. I think I am over thinking this...

[screamingchief]

Originally Posted by Johnny406

I just didn't think it would like the spray so much with the tight LSA

I dont claim to be an expert on the topic per-se,but here is how I see that deal.

Cam choice relative to nitrous use typically depends on just how much HP one plans to add to the combo via that method.

So I ask how much HP are you planning to spray this with?

Anything under say 175 to 200 hp,and you would likely do just fine with a tighter LSA solid cam like the 290b6.

But more than that and yeah,you would typically want to widen the LSA some,and maybe advance the ICL some,and put a very healthy I2E split on the cam choice for that sorta deal.

As I understand that,it runs kinda along the lines of the law of diminishing returns,the more HP you'd spraying in a combo like that,the more it would become a concern.

But do note that the static compression ratio can play into that dynamic as well.

So,the higher the static CR is,the less likely you would be to opt to use a tight LSA cam with a big HP nitrous shot.

Engines built for big nitrous HP are'nt known for having super high cranking compression numbers.

Something like 170-180 psi cranking compression would be pretty normal for a nitrous motor.

As I understand it,the primary goal with a nitrous cam is heat control,too much combustion heat kept in the motor too long can lead to problems,so valve event timing becomes a really important factor on higher HP nitrous combos,especially a valve event like the Exhaust Opening valve event.

But yeah,by all means it would be a good idea to consult with an expert on that kinda deal.

FWIW

Bret P.

[Johnny406]

Just got off the phone with a guy named Steve @ Comp Cams, here is his recommendation for a solid flat tappet grind shoot a occasional 150-175 shot. FYI: I didn't know this but Comp does have a cam saver solid lifter for us, part#800-16

Manufacturer's Part Number 51-247-4
Part Type Camshafts
Product Line COMP Cams Magnum Solid Camshafts
Summit Racing Part Number CCA-51-247-4
UPC 036584641506

Cam Style Mechanical flat tappet
Basic Operating RPM Range 3,000-6,500
Intake Duration at 050 inch Lift 260
Exhaust Duration at 050 inch Lift 260
Duration at 050 inch Lift 260 int./260 exh.
Advertised Intake Duration 306
Advertised Exhaust Duration 306
Advertised Duration 306 int./306 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.555 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.555 in.
Valve Lift with Factory Rocker Arm Ratio 0.555 int./0.555 exh.
Lobe Separation (degrees) 110
Computer-Controlled Compatible No
Grind Number 306S
Valve Springs Required Yes
Camshaft Manufacturers Description Race idle, pro street. Needs increased compression and 3500+ stall. Limited street use.

[screamingchief]

Originally Posted by Johnny406

Just got off the phone with a guy named Steve @ Comp Cams, here is his recommendation for a solid flat tappet grind shoot a occasional 150-175 shot. FYI: I didn't know this but Comp does have a cam saver solid lifter for us, part#800-16

Manufacturer's Part Number 51-247-4
Part Type Camshafts
Product Line COMP Cams Magnum Solid Camshafts
Summit Racing Part Number CCA-51-247-4
UPC 036584641506

Cam Style Mechanical flat tappet
Basic Operating RPM Range 3,000-6,500
Intake Duration at 050 inch Lift 260
Exhaust Duration at 050 inch Lift 260
Duration at 050 inch Lift 260 int./260 exh.
Advertised Intake Duration 306
Advertised Exhaust Duration 306
Advertised Duration 306 int./306 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.555 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.555 in.
Valve Lift with Factory Rocker Arm Ratio 0.555 int./0.555 exh.
Lobe Separation (degrees) 110
Computer-Controlled Compatible No
Grind Number 306S
Valve Springs Required Yes
Camshaft Manufacturers Description Race idle, pro street. Needs increased compression and 3500+ stall. Limited street use.

Well,IMHO the 290b6 would be at least as good a cam (if not better) for a 150-175 hp shot than that ^^^^ one would be.

Hardly anyone I know runs a single pattern cam with nitrous...

Me,I'm not a fan of single pattern cams for pontiacs period.

As I understand it,the main thing a wider LSA brings to the table for a serious nitrous cam is typically an earlier EO event for that given cam,as that helps let some of that extra combustion heat outta the chambers earlier to help keep things from going into "meltdown" mode.

That and less overlap helps to keep any of that spray hp from going right out the exhaust pipes.

If you felt you really needed that,I'd just get Comp to grind you a 290b on wider LSA.

Here is what that 306s looks like:

Brand & part no.: Comp #51-247-4
Grind & lobe no.: #P 306S-10 ~ Lobe #6003 (Magnum solid)
Tappet type: Solid Flat Tappet
Spec = intake/exhaust: (notes)
Adv.dur. = 306°/306° (I/E split = 0°) (Adv.dur. rated @ .015")
Dur. @ .050" = 260°/260° (I/E split = 0°)
Dur. @ .200"= 164°/164° (I/E split = 0°)
Lobe lift = .370"/.370"
Lift @ 1.5 rr. = .555"/.555" (Gross lift) (For Net lift subtract lash)
Lash = .022"/.022"
LSA = 110° ICL = 106° ECL = 114°

Advertised/seat events:
IO = 47° BTDC
IC = 79° ABDC
EO = 87° BBDC
EC = 39° ATDC
Total OL = 86°

.050" events:
IO = 24° BTDC
IC = 56° ABDC
EO = 64° BBDC
EC = 16° ATDC
OL @ .050" = 40°

And here is what the 290b would look like if it were custom ground on the same 110° LSA/106° ICL/114° ECL as that 306s cam is ground on:

Brand & part no.: Comp Cams custom
Grind & lobe no.: Grind no.290b10 (lobe #6061/#6013) (Hi torq./Hi RPM lobes)
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 = 110° ICL = 106° ECL = 114°

Seat events:
IO = 39° BTDC
IC = 71° ABDC
EO = 86° BBDC
EC = 38° ATDC
Total O/L = 77°

.050" events:
IO = 21.5° BTDC
IC = 53.5° ABDC
EO = 67° BBDC
EC = 19° ATDC
O/L @ .050" = 40.5°

Now compare that 290b10 to the 290b6 specs posted earlier by 69Goat1,and take notice that the intake events remain the same in both those cams because the ICL remained the same (106°),so all that changed by upping the LSA to 110° is that it pushed the ECL out to 114°,and that change took out some overlap in the process.

And do note that the 306s is rated @ .015" while these 290b's are rated @ .020",so the 306s appears to be slightly "bigger" than it would be if you also measured that 306s cam @ .020" like the 290b is rated at.

Anyhow,in this case,if you look closely at the valve events on the two cams I've posted here in this post,maybe you'll notice that the more than ample I2E split of the dual pattern 290b10 (14° adv. & 11° @ .050") cam accomplishes pretty much the same end result as the additional duration (seat/.050") does for the single pattern 306s cam.

Now no doubt when that 306s is compared to the 290b6,the valve event differences are a bit more noticable,but remember that at least part of that apparent difference is due to the differences in where those two given cams are being rated at,as the most noticable differences are for the seat events,where-as the .050" events are'nt all that far off from one another.

The only thing that I can clearly see the 306s would offer over the 290b cams would be slightly later intake events (seat/adv.),which would likely net slightly lower cylinder pressures overall,which @ a higher altitude like you're at,I'm not too sure if that would be a desirable thing.

Which kinda goes back to what I said earlier about how this also often depends on what the static CR will be for this combo???

Anyhow,I probably would'nt sweat all that ^^^^ "nitrous" cam stuff over a relatively small 150-175 HP shot,me I'd just run the 290b6 seeing as you already have it.

I say that as the 10:1 CR 406 for my racecar has a custom Crower 256°/260° solid on a 108° LSA (104° ICL/112° ECL),and I plan to spray mine w/at least as much hp as you're talking about spraying yours (maybe even just a bit more when I get the lower hp nitrous tunes cleaned up nicely),so you can see why I'd feel that way.

FWIW

Bret P.

[Region Warrior]

Agree with Bret.
Use what you have.
If set on new tell Greg want one like mine with 10 more duration.

[Johnny406]

Thank you so much for your input gentlemen!! I agree Bret, I thought it was a strange choice for a cam as well and told the guy as much.

With that said, I called P-Dude this morning and we chatted for a little bit. I'm going to get the complete flow numbers from the guy that flowed them (he misplaced them when I picked up the heads) and I'll send that info as well as verify the head cc's and I'll have Ken spec and have a cam grind for it.

I'm still itching to try that 290b6, I may stick it in the old 406 when Jack Ferris finishes those heads. I have two sets of domed pistons if needed but that's for another thread