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The cam is a Howards grind, not sure how different it is form the GM grind. Listed as a (219/228 @ 112 .525). I know the Hot Cam isn't the best grind out there, but I got it for a steal so I'm running it.
I rarely hear about them being run in a 4.8? I know they were considered a bit on the wimpy side for an LS1, they may be a little more rowdy on the smaller 4.8. Anyone have experience with one in a 4.8?
I run a Howards cam from TMS, and they told me their lobes were not super aggressive...although they never said which lobes they actually were. It's always made me wonder to be honest...
Not all howards lobes are aggressive. I do know the howards asa grind is around a 48 lobe...the hot cam is not quite that agressive.
If you want to know exactly what it is just subtract .050 duration from the advertised duration and that will give you the lobe angle. Anything less then 49 is agressive, anything above 53 is mild.
Not all howards lobes are aggressive. I do know the howards asa grind is around a 48 lobe...the hot cam is not quite that agressive.
If you want to know exactly what it is just subtract .050 duration from the advertised duration and that will give you the lobe angle. Anything less then 59,is agressive, anything above 53 is mild.
Good to know. I'm gonna check that out now actually. Thanks
Local Oshkosh Wisconsin company I've used a ton of their gen I flat tappet stuff in roundy round motors with terrific success. They are made here with modern CNC machines even though the name originated from California back in the 50-60s flat head era
I managed to find a lobe list from the downloads section of their web page
According to the list Jim posted the cam lobe in question has a advertised duration of 267.2 and a .050 duration of 219 on the intake. Subtract the 2 numbers = 48 lobe...very agressive.
I don't understand how you can verify the lobe "aggressiveness" by the durations? They don't give you any indication of the lobe design or ramp rate.
For example I know the GM version of this cam has a very mild lobe on it. Yet it has the exact same advertised duration. You can use a factory LS6 spring on it and it was designed to be easy on the OEM valve train with lazy ramp rates.
I get Howard's may very well be an aggressive lobe and not mimic the GM version. But going off the duration numbers doesn't make sense to me?
Last edited by Forcefed86; 05-29-2016 at 09:53 PM.
Rise over the run is the ratio which describes the intensity. Or jerk if you will. Advertised minus @ .050" where a 53 or 54 means the ramp speed or "lifter kick" is a bit more gentle or delicate than a 47-48
You're right that @ .200" and .300" numbers would also tell a greater story and you still wouldn't know if the lobe shapes are symmetrical or not. My understanding from talking to a pretty good tech guy at Competition Products (parent company) is they do modify the closing flanks to prevent valve Bounce which bleeds off cylinder pressure
For your situation a PSI 1511 is probably more than sufficient.
I don't understand how you can verify the lobe "aggressiveness" by the durations? They don't give you any indication of the lobe design or ramp rate.
The difference between advertised (.006") and duration at .050" indicates the ramp rate. If it takes 80+ degrees to bridge that .044 gap, then obviously it has a slow ramp rate. If it takes just 30 degrees, then obviously the ramp rate is rather violent. A violent ramp rate will also hold the valve open closer to peak lift for longer, think of it as TDC dwell time with a very high rod/stroke ratio.
For the record here is the GM LS1 Hot cam VS Howards version.
The GM appears to be a 53... Howards a 48.
I picked up a set of 241's with BTR dual .650 springs already installed. Figure I'll have plenty of spring. I was just under the impression I was buying "gentle" cam... Guess not! Hope it works well in the little 4.8.
The ramp rate on a cam with that low of lift doesn't really matter as much as if it were a .600+ lift cam, at least not in the valve spring department.
It does mean that the valve will open faster, spending more duration near peak lift. Helps a lot with flow/power figures on a cam without much lift. It will likely outperform the original GM hot cam.
05-27-2016, 01:34 PM
GM hot cam in a 4.8? Results? Dyno numbers? 
