Looking for a good open cam for the Briggs animal

A

Atv999

Member
I'm looking to get more power out of my animal. I run an open smallblock class, weight limit is 350 lbs and I'm at 420 lbs. I currently have a big valve head, .335 Dyno cam, 1.25:1 roller rockers, comp cams pushrods, 38lb dual valve springs, .010 faster motors piston, arc billet stock length rod, stock crank, .045 MLS head gasket, mikuni 28mm flatslide carb on methanol, 34 degrees timing, stock pvl coil and flywheel. Head coilbinds at .430. I'm giving up 50-70 lbs on all the other guys and im wondering if I can gain a little more so I can be more competitive. 580-700 ft oval dirt tracks. Thanks in advance
 
You could try the 356.
No replacment for displacment though .
Flathead crank with corresponding rod and piston .
Thats not a drop in though .
Jimbos high compression piston may help , along with a cam change .
 
I like the p open and the 356.

Only ran either with stroker motors.
Free flowing head and intake is important.
Both cams like rpm in zero install .Comes down to what durability you can live with.

What do most run for gear?
I'm a fan of smaller driver than most for grunt off the corner.
I run a 9 where most run 11s.
 
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I have the faster motors dome piston in it now. If I go with the 356 or p open grind. I'll have to remove the faster motors 1.25:1 roller rockers won't I? Is that a better way to go? Im willing to try anything at this point
 
You can go with the 356 but unless you go to longer valves with bigger dual springs you'll coil bind with the 1.25 roller rockers. Honestly I'd make it a stroker motor. The only drawback is it's not cheap. I've built many of them if you decide to go that route. I'd be happy to help you out.
 
Yes if you have .430 coil bind . Your at max lift now . So a cam change with more duration , would be next . Its a balancing act , bigger carb would be easy . Where , when and if you get improvement is the main question .
 
bpoirier said:
You can go with the 356 but unless you go to longer valves with bigger dual springs you'll coil bind with the 1.25 roller rockers. Honestly I'd make it a stroker motor. The only drawback is it's not cheap. I've built many of them if you decide to go that route. I'd be happy to help you out.
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I actually have a stroker too but I'm trying to run with a stock crank build. My stroker has a big valve head, faster motors 1.25:1 roller rockers also, raptor 3 crank, comp cams .310 billet cam, 38lb valve springs, comp cams pushrods, .045 MLS head gasket, rapp .990 j pipe, tillotson x380 carb and intake, arc long rod, faster motors dome piston, and arc duel bearing crankcase cover. That head coilbinds at .430 also. 34 degrees timing on stock pvl coil and flywheel. Any improvements on this one? Other than a billet head lol
 
flattop1 said:
Yes if you have .430 coil bind . Your at max lift now . So a cam change with more duration , would be next . Its a balancing act , bigger carb would be easy . Where , when and if you get improvement is the main question .
Click to expand...
My main issue with this engine is the lack of bottom end to mid power
 
Advancing could help with low end .
What rpm range are you using currently?
Sounds pretty well thought out already .
Can you run more gear ?
 
Lose the 3-disk and go with 2-disk. That’ll help takeoff. At least run an aluminum basket, if you’re dead set on the 3-disk.
 
According to the cam card, target rpm should be much higher.

Advance the cam 4 degrees. Be sure to check valve to piston clearance after you do this. especially with the dome piston and long duration cam.
May only be able to get away with 2 degrees.

I think right now, you are below the powerband the cam likes with rpm. Just a gearing change may wake it up, however, durability may take a shot.
 
I believe dyno said for evey 2 degrees your rpm peak changes 300 rpm .
So advancing it would bring it down , more low /mid power where your wanting it .
Timing event change is why the need to check valve too piston clearance.
Question : with the ratio rockers aren't the timing events also altered .
IE: most cams are designed with out ratio rockers in mind , so opening and closing numbers are set with that in mind .
 
95 shaw said:
According to the cam card, target rpm should be much higher.

Advance the cam 4 degrees. Be sure to check valve to piston clearance after you do this. especially with the dome piston and long duration cam.
May only be able to get away with 2 degrees.

I think right now, you are below the powerband the cam likes with rpm. Just a gearing change may wake it up, however, durability may take a shot.
Click to expand...
If I have the Dyno cams 335 grind cam, do I just pull the cam and turn the whole cam? It's not a marked billet cam
 
No.
I assumed you had a billet cam.
That limits the possibilities. Makes the billet cam seem like a lot better value though.
I am sure someone has made a multiple keyway cam gear for the animal. Horstman used to make one for the flathead.
I searched a little, but was unable to come up with one.
 
flattop1 said:
I believe dyno said for evey 2 degrees your rpm peak changes 300 rpm .
So advancing it would bring it down , more low /mid power where your wanting it .
Timing event change is why the need to check valve too piston clearance.
Question : with the ratio rockers aren't the timing events also altered .
IE: most cams are designed with out ratio rockers in mind , so opening and closing numbers are set with that in mind .
Click to expand...
Timing events are usually specified at a certain valve opening. Some manufacturers use .008. Some use .020 for opening/closing point.
Ratio rockers alter that to .010 or .025 at the valve. If checked at the pushrod, numbers would be the same as cam card. A change in valve lash will bring back into spec at valve.
Nothing changes at lobe centerlines.
 
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