big cubes and idle

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cudaFS

cudaFS

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I've searched the forums but need just a little more exact info, I know larger displacement mellows out larger duration cams, I'm looking for a hyd roller cam for a 496 that has street manners, I get the definition of manners is relevant, so in this case, my definition is the longest duration @ 50 cam that works best at mid 500 lift with with just a hint of lope at idle.
Thanks
 
cudaFS said:
I've searched the forums but need just a little more exact info, I know larger displacement mellows out larger duration cams, I'm looking for a hyd roller cam for a 496 that has street manners, I get the definition of manners is relevant, so in this case, my definition is the longest duration @ 50 cam that works best at mid 500 lift with with just a hint of lope at idle.
Thanks
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I guess I should list the sweet spot, 2000 +/- to 6000 +/- rpm
 
cudaFS said:
I guess I should list the sweet spot, 2000 +/- to 6000 +/- rpm
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Might look at compcams 292 extreme hyd roller, its a step down from the extreme solid roller that I like so well .
 
cudaFS said:
How's it idle
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sounds like a hot rod, but aint that wild . The solid roller idled at 1150 for me ----------in a hot 406 sbc, and a 505" wedge. I had to downsize one step to make my f.inj. work right in the 505.
 
cudaFS said:
I've searched the forums but need just a little more exact info, I know larger displacement mellows out larger duration cams, I'm looking for a hyd roller cam for a 496 that has street manners, I get the definition of manners is relevant, so in this case, my definition is the longest duration @ 50 cam that works best at mid 500 lift with with just a hint of lope at idle.
Thanks
Click to expand...

I have a custom 239/245 hyd roller in my 496 that is nice and smooth down low but makes 610 hp and 630 torque. My last engine was a 512 with a 246/246 hyd roller and it was a little lumpy at 900 rpm and lacked a little bit of torque down low which is why I built a new engine. It can be difficult to get the correct cam when you're looking for good street manners. You might need to try at least a couple of cams before you hit the target. Most engine builders are interested in peak power so when you ask them about a smooth idle and good street manners they might not have a "go to" cam for that.
 
@ Andy, that 512 must be a beast! now that 496 of yours, thats right in the ballpark. you're right about the cams, so many just dont get the smooth idle thing. I've been researching cams for hours a day for a week, and I haven't come across a lot of idle characteristics info. BUT...what I've found mirrors your post, 242 and up intake seems to be where the lope starts. my short list is 238 /242 and a 242/246 hughes cam. in your opinion which would you choose?
 
Mind cluing us in as to what kind of cam you're wanting here? Flat hyd, solid? Roller hyd, solid?
 
cudaFS said:
its in my post, hydraulic roller
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I'm sorry. I missed it somehow with my blind ***. My bad. So, just so I have it right NOW, 496, street manners with maybe a hint of lope, right?
 
cudaFS said:
yep, you got it.
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Ok, simple. Remember, rollers have WAY different profiles than flat tappets, so you have to be more conservative if you don't want a really choppy idle. I would say no more than 240@ .050 and probably a little less and on a 112 LSA. The 112 will give you the street manners and good vacuum signal for a strong idle and you can even run power brakes if you want to. I would say probably an optimum place would be like 236/238 @.050 on a 112 with lift "wherever" you want it to be.
 
thanks rusty, I was hanging up on the roller profiles too, I wasnt understanding roller profiles, I didnt know if they acted bigger than their listed duration or smaller.
 
cudaFS said:
thanks rusty, I was hanging up on the roller profiles too, I wasnt understanding roller profiles, I didnt know if they acted bigger than their listed duration or smaller.
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They do act bigger, especially hydraulic rollers. That's why you need to watch it if you don't want too rough of an idle.
 
AndyF said:
I have a custom 239/245 hyd roller in my 496 that is nice and smooth down low but makes 610 hp and 630 torque. My last engine was a 512 with a 246/246 hyd roller and it was a little lumpy at 900 rpm and lacked a little bit of torque down low which is why I built a new engine. It can be difficult to get the correct cam when you're looking for good street manners. You might need to try at least a couple of cams before you hit the target. Most engine builders are interested in peak power so when you ask them about a smooth idle and good street manners they might not have a "go to" cam for that.
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Andy, whats the lsa on the 239/245 cam? Also what heads, intake, and carb are on it?
 
112 lobes, Trick Flow 240 heads, Trick Flow intake and a Holley Sniper.
DSC_3449 (Large).JPG
 
RustyRatRod said:
They do act bigger, especially hydraulic rollers. That's why you need to watch it if you don't want too rough of an idle.
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@ rusty, I'm going to keep the cam at 238/242/110 I cant afford a custom grind, and huges sells that one for 419.00. thanks again for your knowledge
 
cudaFS said:
@ rusty, I'm going to keep the cam at 238/242/110 I cant afford a custom grind, and huges sells that one for 419.00. thanks again for your knowledge
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Have you though of a regrind? I believe Oregon Cam will regrind what you have for 125 bucks.
 
I never thought of that, I'm going to have to take a look at that option. good idea
 
My 470 idles at 750-800 with a Comp XE285HL, it’s got the Holley Terminator.
 
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