Cam recommendation for a 426 SBF

[AllNatural]

All Camshaft Experts - I'm second guessing myself so I decided to ask the smart folks. Combo is:

Mustang 2900 lbs, 3:73 gear, Glide, 3000 stall, 28x10.5 slicks or 275/60/15 drag radial
400HP or more of nitrous (track conditions depending)

426 SBF (4.130 in bore, 4 in stroke, 6.250 rod)
13:1 compression
AFR 225 heads out of the box, 72cc chamber
Victor 2828 intake (no porting) with 1050 Pro Systems
2 inch primaries to a 3.5 collector
1.6 ratio rockers (Jesel)

Right now cam is a Comp .700/.705 on 273/285 at .050 on a 114 installed straight up (can't advance or retard - clearance issues. It needs 6 advance to get to split overlap). Have tried a .680/.680 on 268/280 at .050 on a 108 installed at 104 ICL for split overlap (UD Harold cam). Car has run same MPH on same amount of nitrous under similar environmental conditions with both cams.

Cranking pressure is lower than expected with both cams (around 150). Smaller cam has 58 degrees of overlap, larger has 50 degrees.

Any/all recommendations are greatly appreciated.

[user-612937456]

I like the first cam better but it should be st about 105 LSA and your stall is too low I think it would like about a 4500 min or a 5000 even better

[AllNatural]

GVX,

Yes, the first cam is significantly retarded now (need to notch the valve reliefs more to fix that issue). Depending on what comments I get will start me on the path to "better than I have now".

Thanks for the advice.

[user-612937456]

With that much piston speed and that head your going to need everything to happen soon, not later.

.700/.650
264/267
109
Above base on peak HP rpm of 6800.

Going to need a 2" header on this thing also.

Help me learn Mr. Straub not being critical at all. How come the reduced exhaust lobe but a increase of a 2" header Because of the large shot of NOS? If you don't care what is the reasoning of this wider LSA in a larger displacement app

[AllNatural]

Thanks Chris. Question - why only .650 lift? I see many more cams being ground with less exhaust lift so I'm sure it has been proven to make power. Thanks in advance for the explanation.

[user-612937456]

Thanks Chris. Question - why only .650 lift? I see many more cams being ground with less exhaust lift so I'm sure it has been proven to make power. Thanks in advance for the explanation.

Peak velocity on the exhaust is at low lift. The exhaust is under pressure. As soon as you crack the valve on the exhaust side it is a release of pressure....a blow down. You need just enough lift to for the valve path then you want to shut it as soon as possible to start over again. Total opposite on intake. Your velocities are in a constant increase. Peak velocity on intake side for the most part are somewhere between .400 to .700 valve lift.

I was thinking the same thing. I understand better now I think. Considering peak velocity its about moderation use only what is necessary to do the job. In this case its benefit is to improve the life of the exhaust valve-train and and reduce potential premature failure's?

[AllNatural]

So with a properly sized header, velocity is Increased which assists cylinder filling during overlap resulting in increased VE. Makes sense.

[CamKing]

Here's what I recommend.
Cam# F351w, R79480-82460-115
266/276 @.050"
.480"/.460" Lobe Lift
115 LSA
112 ICL