Cam for 406 mud racer

[Walter R. Malik]

The larger valve duration will not move the RPM point of peak horsepower up much, but what it will do is increase the power that is made UP AFTER peak horsepower, extemding the usable rpm range up. The tradeoff will be low rpm torque. You must keep the engine rpm way up.

Comp has a whole series if .323" lobe lift MA series sft cams that when used with 1.7:1 rr will be .550" lift rule legal.
Durations from BIG BIG thru small
You would have to A-B test it on track against your new Bullet/Ultradyne grind cam.

If I remember correctly, Comp also has a series of .367" lobe lift rollers.

[F-BIRD'88]

The larger valve duration will not move the RPM point of peak horsepower up much, but what it will do is increase the power that is made UP AFTER peak horsepower, extemding the usable rpm range up. The tradeoff will be low rpm torque. You must keep the engine rpm way up.

Comp has a whole series if .323" lobe lift MA series sft cams that when used with 1.7:1 rr will be .550" lift rule legal.
Durations from BIG BIG thru small
You would have to A-B test it on track against your new Bullet/Ultradyne grind cam.

If I remember correctly, Comp also has a series of .367" lobe lift rollers.

Yes they do. The "CR Lift Rule" lobe series. They also have a TK Lift rule .347" lobe series good with 1.55:1 rockers.
A roller cam set makes a lot of sense for this job.

If a 1.3:1 rocker ratio is used there are tons of great .420" lobe rollers to select from for just under measured .550" valve lift.
How is this .550" lift rule checked per rules?

[mdabbott2009]

I tried calling bullet today to talk with Chris to understand what and why I'm sure there is a reason for everything


I filled out a form with jones which actually was close to what bullet sent us

Also what was in it before was a stock rod 406 stock vortecs pretty much, and a 248@.50 flat tappet #7 cam and it would not turn past 6k less it was free revved pretty much

Yes in mud these guys are spinning everything hard ford guy is turning 9k and 10.2 on slick track

[F-BIRD'88]

Forget about 9K with these small port heads..
Cams you can try out to see if "afterpower" does increase at +++6000 rpm. Isky #201070 Z-70.. The hot lash is .028" hot You can try smaller lash to see if extra seat duration helps afterpower or not EG .012-.015" lash..
You can tryout adjusting the cam installed position.
Retard can help top end but may not..

Its up to you to try for effect..
Another is Isky #201060 Z-60 or popular #201547 547-A
Again play with lash and in/ex centerlines for effect on top end..
Effect will be modest.. Head ports size limits this..
May want bigger tube headers..
These are .550" lift rule legal off the shelf choices to try out.

A 406 sbc with vortecs will not be a super high reving engine. You are on the down side of the horsepower curve by +6K rpm.
Isky 547-A is popular because it works very well overall.

[MELWAY]

The crane F-256 cam work well in a restricted head 406 sbc
But peak power will be 6600-6800. But make a ton of TQ below that