Itsallgood995

Was thinking about swapping out my cam this winter. Currently running the GM 454HO roller cam(I210/E230). Does the intake duration, exhaust duration or the differrence between the two effect the RPM range. I assume its the intake but I've seen dynos where they run this same cam to 5400 RPMs?

What is the basic RPM range for a 210,218 or 224 cam?

jeffswav

Call RMbuilder, AKA Bob Mandera, AKA Marine Kinetics, he is a cam expert. He will talk your ear off about cam specs. I told him what I wanted and he made it work. Typically higher duration means higher RPM range, higher lift is more power within that range. But there is way more to it than that.

Itsallgood995

Yeah, He is the man. Hate to bug him unless I'm ready to pull the trigger. Just thinking out loud now, trying to get a better basic understanding of duration rpm ranges.

getrdunn

as stated above bob would be able to help you much more than me however i can help you out a little anyway. the 210/218 would more than likely be pull up to 4900 to 5000 rpm and the 224 perhaps just slighly more. there isn't much difference in duration between the two. you can get a pretty good idea of what the duration does to a cam by just going to the cam websites and look at all the different cam lobes vs. rpm's. a good proven cam for your application would be something similar to the 731 crane cam. 230/236 - 598/610. these specs may not be exact however are close. this would probably be as large as i would go with a 454 and your desired rpm range. your cam timing also plays a big part in cam choices as well. cylinder head volume and comp. dictates much of the cam seat timing. this is where you will find the cam experts like bob who can put all these factors into place and come up with a good grind for your application. i recently went through the same thing with my 496's and had dean gellner help me out with some grinds. he is also known to make some pretty good power.

good luck and have fun serving some of the cam sites. there is endless amount of info on the internet about camshafts and you can learn a lot.

Griff

What are the lift numbers??????? 210 intake to a 230 exhaust is a huge difference.

You need to have good exhaust when you start going to bigger cams. Both to prevent reversion and to let the engine breath.

Itsallgood995

Lift is 511/540 114lsa
I think this cam is best fitted for the Rec heads it was designed for & not ideal for my ported vortec heads.

My exhaust is 496 take offs w/ Corsa Q&Q. Wouldn't the 236 exhaust duration on the 731 cam be a reversion issue w/ my exhaust?

getrdunn

i really doubt it. i'm sure there are many boat engines with this cam and using even stock exhaust. maybe some of the 731 users will post their results.

Griff

I doubt the 731 or similar can be used with 496 exhaust and Q&Q without reversion. The 731 also has 112 lob sep. I would say you are close to your limits. You could probably increase intake lift and duration up to about 226, but I would try and keep the lobe sep at 114.

Talk to Bob M/rmbuilder when you are ready to do the upgrades.

jeffswav

As a rule most aftermarket cams are not suitable for stock exhaust. You need long risers to avoid reversion. I had a flat tappet hyd Crane with about 230 duration and I got excessive moisure in the engine with stock exhaust. I now have the EMI thunders with long risers.