Calling All Cam experts!!

[JayBird]

Hey, I'm no cam expert, but I do have my own personal experience and dyno time on my engine with a comp hydro roller cam. I have close to the same spec cam as you on a 355 sbc and mine made 470hp and 460 tq. I suspect yours will be in the 425-450hp range when properly tuned.

Here's what I have found out about hydro roller cams. The rpm limit is around 6000-6200. My limit was 6200 with comp cams 929 springs which is on the heavy side as far as seat pressure, etc for hydro lifters. After speaking with comp I switched to the bee hive springs which bumped up the rpm to 6600-6700. Anything after that on the engine dyno shows vallve float. You say the valves are not floating, but I would bet they are after 5800-6000. I also think (my personal opinion) that the rev kit does not increase rpm limit, it can help lifter stabilization, but that doesnt necessarily mean more rpm.



I am in no way putting down hydro rollers. They work great for what they are meant for. I am currently switching to a mech roller so I can turn a few more rpms.

I think the cam you have is a good choice for what your intentions are. My only suggestion would be to chassis dyno it or engine dyno it if you could and change to the bee hive springs and you would see exactly where your rpm limit is and also be able to detemine where valve float occurs. I can drive my car and turn it to 7000, with no audible signs of valve float, but per the dyno I know after 6700, in fact it is floating the vlaves. At 7200, I do then hear signs of valve float in the car. I have only done this once. This is not something you would want to consistantly do.

Again, once properly tunedm, I think you will be happy with the power the hydro roller makes, just you cannot turn them higher rpms like a solid roller.

my 2 cents,

Feel free to ask me questions if you like. I am no engine builder, but I have spent alot of dyno time and $$ with my engine builder finding these things out.

Jay

[Travis B]

Hey, I'm no cam expert, but I do have my own personal experience and dyno time on my engine with a comp hydro roller cam. I have close to the same spec cam as you on a 355 sbc and mine made 470hp and 460 tq. I suspect yours will be in the 425-450hp range when properly tuned.

Here's what I have found out about hydro roller cams. The rpm limit is around 6000-6200. My limit was 6200 with comp cams 929 springs which is on the heavy side as far as seat pressure, etc for hydro lifters. After speaking with comp I switched to the bee hive springs which bumped up the rpm to 6600-6700. Anything after that on the engine dyno shows vallve float. You say the valves are not floating, but I would bet they are after 5800-6000. I also think (my personal opinion) that the rev kit does not increase rpm limit, it can help lifter stabilization, but that doesnt necessarily mean more rpm.

I am in no way putting down hydro rollers. They work great for what they are meant for. I am currently switching to a mech roller so I can turn a few more rpms.

I think the cam you have is a good choice for what your intentions are. My only suggestion would be to chassis dyno it or engine dyno it if you could and change to the bee hive springs and you would see exactly where your rpm limit is and also be able to detemine where valve float occurs. I can drive my car and turn it to 7000, with no audible signs of valve float, but per the dyno I know after 6700, in fact it is floating the vlaves. At 7200, I do then hear signs of valve float in the car. I have only done this once. This is not something you would want to consistantly do.

Again, once properly tunedm, I think you will be happy with the power the hydro roller makes, just you cannot turn them higher rpms like a solid roller.

my 2 cents,

Feel free to ask me questions if you like. I am no engine builder, but I have spent alot of dyno time and $$ with my engine builder finding these things out.

Jay

what heads are you running??? How much compression? What solid roller are you going to go to?

[TurboLark]

I personally hate single pattern cams for just about everything out there. A good dual pattern would help usually. With a 383 you can us a little bit larger cam. You didnt say at what lift the head flow was at, but normally I like to run .025-.040" more lift than the peak head flow(the valve goes past that point twice this way). For duration I would be looking at 232-236deg int and 238-244 deg exh at .050. something in the 110-112 lobe seperation would be nice. In this situation, i would prefer to use a solid roller to avoid the potential valve float problems.

Main thin at this time is to get fully tuned to see where you are at, and then determine if you are happy with it or not.