selecting a 406 track cam

grumpyvette

grumpyvette

Administrator
Staff member

hey grumpyvette?

i want help picking a cam for a new 406. going in a 1970 nova stock weight with th350 trans and 4.11 gear.
It has 11.6 compression and RHS 220cc heads with 780 holley and vic jr. intake. going to play with it at the track only. 1/8 mile track.

We want a solid flat tappet to go in this thing. he cant afford a roller right now for it.
was thinking 256/264 at 50 with .537/.557 at 105 cl

thanks





http://www.cranecams.com/?show=browsePa ... e=camshaft

ID suggest this cam with 1.6:1 roller rockers, and a 4000rpm-4500 stall converter as its KNOWN to maintain decent valve control and has produced very reliable hp in many previous engines similar to what your building, Ive used it frequently with good results.
keep in mind that valve train control is critical to reliability, and your piston speed in a 406 limits you to about 6500rpm-6800rpm if you intend to maintain reasonable durability.
keep in mind , your nova probably weights 3300lb or more with you in it, and its rare to get a th350 to shift correctly and consistently and maintain durability at over 6500rpm even with a manual control, so potential power made over that rpm, is never used, and with tires that fit that nova youll be turning less than 6500rpm in the lights in top gear.
yes theres larger cams but theres a compromise, your trading low rpm torque for a bit more high rpm peak hp, and with that rear gear and car weight, the trade-off with the larger cams usually not in your favor, remember,your looking to maximize the AVERAGE torque and AVERAGE hp in your effective rpm band NOT just the PEAK HP/TQ numbers

if your really dead set on maximizing the cam duration, you could jump to this crower grind,below, its always produced impressive results, but again its a trade-off and while youll gain more peak hp...I doubt the car will be faster

yes you need to verify ALL valve train clearances and geometry

http://www.crower.com/misc/cam_spec/cam ... &x=23&y=12



why not make a few calls and discuss it
1-866-388-5120 crane

619-661-6477 CROWER
 
"grumpy that crane cam is the same one we had in it before we got the new heads. we had it in there with 200cc dart SP2 heads it ran 7.35 in the eight. now we got the new 22o RHS heads and thought we would change cams."





if your sure you want a larger cam, the crower is an upgrade in peak hp, but Im not 100% convinced from previous builds that its average hp is going to be a marked improvement, simply because your gaining peak hp in exchange for less mid rpm tq, which in a heavier car with an auto trans may not be a great trade off.
yes the larger duration and higher lift of the crower looks like its a marked improvement, and yes theres a noticeable, improvement in head flow with the larger heads, so I can see where thats very tempting, since you already have the crane grind installed,please test the current cam then when you go to the larger cam let us know what you think of the trade off

now if the car had a 4.56:1 rear gear and weighted about 3000lbs with you in it Id have suggested the larger crower grind in your application without hesitation
ID also have suggested upgrading the intake
http://www.summitracing.com/parts/HLY-300-110/
hly-300-110.jpg



why not make a few calls and discuss it

1-866-388-5120 crane

619-661-6477 CROWER
 
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