cam for 231 for max power 5500 RPM

Blazer406

Mechanical Engineer
Hey guys...

Looking for another cam selection opinion..... I have a stock (at the moment) long block on my '87 GN. I have just purchased a TE45A turbo. I have a spare set of 8445 heads and stock intake with doghouse. I was considering hand porting my spare heads and intake and getting ready to swap them out one weekend after I get the TE45A and my 60# motrons. Current mods are in my sig. A 340 pump has been ordered... so it will go on as well. I was thinking I might pull the engine to do the head swap.... cause I was planning on doing the timing chain/oil pump at the same time. This would be a good time to upgrade the stock cam. I was considering something only marginally bigger.... say... make good power til 5500 RPM instead of 4800 RPM. From what I have read... a 206/206 comp cams flat tappet cam might be enough. I kinda want to not have to upgrade my springs (Comp 980's).

So.... how big of a stick do I need to pull to 5500 RPM's on a full weight solid roof street car..(with the hand ported 8445 heads)..?? Will there be any loss of low end? Will it still idle smooth?

I guess... I have one more question.... Is it possible to pull the cam with the engine in the car.... w/o removing the a/c stuff in front of the radiator? If so... I might just do all this stuff in car.....

Thanks in advance.
 
After talking to my brother... who is also a Mechanical Engineer.... and a former employee of Comp.... who helped design some cams... for some race teams on the NHRA circuit (one of which won the championship this year).... said he would step up a little bigger... said the 206/206 was almost stock....

The 212/212 hydraulic flat tappet has an operating range of 1200-5500 RPM. It also recommends the 980 valve springs... which I already have. Is there anyone here running the 212/212 flat tappet Comp Cams cam... and how do they like it? What kind of idle does it have? I really don't want much of a lope.... I like to walk softly... and carry alot of boost :biggrin:
 
Any comp cam you run will probably have some lope,even the 206 had lope in my 3.8.This is due to the 110 LSA they have,which is one of the reasons they make great torque.

I have a local friend with the 212/212 and he was around the same as I was on the 206/206.The real thing that determines how it will work are the supporting parts.

The 206/206 is actually around 10* more duration than stock.

Another great cam is the 204/214 that others have used,has good torque and top end.That one is basically the edelbrock cam for the 3.8.
 
with 204/214 cam in my car the best it ran was shifting at 5850

I have them in stock if you deside

I have other grinds also but that one is most popular but my 214/224 grinds are gaining on them :)
 
with 204/214 cam in my car the best it ran was shifting at 5850 when it ran 10.41 at 133 mph

I have them in stock if you deside

I have other grinds also but that one is most popular but my 214/224 grinds are gaining on them :)
 
Sixgun86GN... I like your numbers in your sig..... If you care to share... email me or PM me your detailed combo.... I would like to be around there at some point. I am also considering locating me a 4.1L production engine to use as a basis for my replacement engine. I could maybe go roller on that engine.... but it might not be necessary.
 
Add roughly 10 degrees over stock (dont know stock duration) to move the powerband up about 500rpm. Look for a cam that gets some decent duration without having to increase overlap. Overlap is the killer. With a turbo motor, there is alot more exhaust pressure than intake pressure, and you end up bleeding exhaust into the cylinder and intake during overlap. Cams that close the intake valve too long ABDC will bleed off alot of cylinder pressure. But with the turbo, this late closing can be beneficial to extra cylinder filling. Give Lunati a call.
 
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