Cam Suggestions

DorianL

solid fixture here in the forum
Staff member
Yes, that does look like an optional item. Why do you think it is needed?

I understand why they are saying it is required. But I’m not convinced that it is. My last retrofit roller didn’t require that or even a mellonized distributor gear. Either way, I don’t like it.

EDIT. Reading through Grumpy’s links most hydraulic roller cam manufacturers now press on a softer metal cam gear so you don’t need to replace the distributor gear.
 
Last edited:

busterrm

solid fixture here in the forum
Looked back, do you know what aluminum heads you have? We could get flow numbers and possibly get a better dyno estimate?
 

DorianL

solid fixture here in the forum
Staff member
Looked back, do you know what aluminum heads you have? We could get flow numbers and possibly get a better dyno estimate?

No idear. The heads are from Racing Power Company (RPC which sounds suspiciously like PRC). All that I know is that they have kidney shaped 64cc chambers, 205 runners, large valves and aluminum.

There is very little information on them out there.

EDIT

I think I found some “as cast” flow numbers

Intake
.1 - 65
.2 - 138
.3 - 188
.4 - 227
.5 - 242
.6 - 248
.65 - 251
.7 - 256
.75 - 254
.8 - 246


Exhaust
.1 - 52.5
.2 - 95
.3 - 123
.4 - 146
.5 - 165
.6 - 175
.65 - 181
.7 - 185
.75 - 188
.8 - 189
 
Last edited:

busterrm

solid fixture here in the forum
Your looking at about 490-500 ft/lbs torque @ 4000 and 440-450 horsepower @ 5000. That would be good for your street vette I think, that’s with the cam you stated!
Again, that’s DD2000, more of a guesstimate!
 

DorianL

solid fixture here in the forum
Staff member
Thanks !!!!!!!! Much appreciated. Very much.

Those are pretty good numbers.

I take it that there’s also a decent amount of torque down low to make this reasonable?
 

DorianL

solid fixture here in the forum
Staff member
It still looks like a good, happy 400. Certainly an improvement over what I have.
 

DorianL

solid fixture here in the forum
Staff member
Out of pure curiosity... can someone do a DDyno for me on this cam: 230/230 @ 0.050 .480/.480 109 ?

Note that my rockers are 1.55

I’m kinda curious to know if this corresponds to my flat bottom end.

Thanks.
 

busterrm

solid fixture here in the forum
The lift would be around .495-6, probably boost duration a couple degrees also. I will run one on DD 2000!
 

busterrm

solid fixture here in the forum
I don't see that as being the correct specs for the conditions you described. With those specs you should have had plenty of torque at 1500, my graph shows around 400 ft/lbs at about 1500 rpms. Max of 440 at about 4000 rpms, about 395 horsepower maxing at 5000 and holding to 5500 then dropping to 376 at 6000. Something is off quite a bit.

A roller with the same specs would be even better, TQ 430 @ 1500 and peak at 4000 of 485, HP peak @ 5500 of 445. So, I am wondering if that may be a custom grind! You said it had no guts at 1500 and didn't show any power till in the higher rpm ranges.
 

DorianL

solid fixture here in the forum
Staff member
Hmmm. Interesting. Yes. At 1500 rpm and lower, it had nothing. It was sufficiently annoying for me to want to do a cam swap. I’m very curious to see the difference. In any case I did learn something about my driving style, I spend most of my time below 2500
 

Indycars

Administrator
Staff member
I don't see that as being the correct specs for the conditions you described. With those specs you should have had plenty of torque at 1500, my graph shows around 400 ft/lbs at about 1500 rpms. Max of 440 at about 4000 rpms, about 395 horsepower maxing at 5000 and holding to 5500 then dropping to 376 at 6000. Something is off quite a bit.
If they did something strange with the cam timing, like retarding it 8° - 10°, that would explain
the NO low end torque.
 
Top