Going to a different cam

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oldhead
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Going to a different cam

Post by oldhead » Thu Nov 08, 2018 8:42 pm

I was wondering if I added 6 more degrees or dropped 6 how much RPM would max. HP. would change? SBC-400 8 to 1 comp,300-235 heads,800 cfm carb,248-260 at .050 114 cl.,making 470 hp at 6250 rpm.Unblown of course...I WANT TO THANK THE GUYS THAT ANSWERED LAST TIME. OLDHEAD
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F-BIRD'88
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Re: Going to a different cam

Post by F-BIRD'88 » Thu Nov 08, 2018 8:52 pm

With the cam you got, reset the valve lash about .008" tighter than its set now and go for a ride or go to the strip and test.

427dart
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Re: Going to a different cam

Post by 427dart » Thu Nov 08, 2018 9:48 pm

Why such low compression?

oldhead
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Re: Going to a different cam

Post by oldhead » Thu Nov 08, 2018 10:20 pm

its always blown,sometimes 26# Oldhead
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gnicholson
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Re: Going to a different cam

Post by gnicholson » Thu Nov 08, 2018 10:40 pm

especially if you only have 8 to 1 compression the cam needs to be tightened up to atleast 108 or 106 . that and the duration needs to be reduced a bunch. how do you only have 8 to 1? is this a blower motor?

oldhead
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Re: Going to a different cam

Post by oldhead » Fri Nov 09, 2018 12:04 am

I am sorry,you didn't understand, I just said "Blown" . That means supercharged. thank you Oldhead
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gnicholson
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Re: Going to a different cam

Post by gnicholson » Fri Nov 09, 2018 12:09 am

all i saw was"unblown ofcourse" ignore everything i said

oldhead
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Re: Going to a different cam

Post by oldhead » Sun Nov 11, 2018 5:26 pm

259 veiws and still no real help. Where did all the smart guys go ? Oldhead PS: Big Joe is with GOD now
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plovett
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Re: Going to a different cam

Post by plovett » Sun Nov 11, 2018 5:51 pm

Well, your original post was a little confusing and your question wasn't worded too well. You have a blower motor, but state the horsepower as "unblown of course". That's going to make it hard for most guys to answer.

That out of the way, I would say 6 degrees duration equals 300 rpm. Of course that is a very general statement, especially considering your engine is not run of the mill by any means.

JMO,

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Re: Going to a different cam

Post by Newold1 » Sun Nov 11, 2018 6:17 pm

Please post non-confusing correct kings english descriptions and details so most of us can understand what you are trying to do!

If Joe Sherman was still on this site with us he would be asking you to do the same. :!:

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Re: Going to a different cam

Post by GARY C » Sun Nov 11, 2018 6:29 pm

I would have guessed 200 to 250rpm but you not going to find many people posting on line that have ever dyno tested a 6 degree cam change, me included.
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oldhead
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Re: Going to a different cam

Post by oldhead » Sun Nov 11, 2018 10:02 pm

Newold1 wrote:
Sun Nov 11, 2018 6:17 pm
Please post non-confusing correct kings english descriptions and details so most of us can understand what you are trying to do!

If Joe Sherman was still on this site with us he would be asking you to do the same. :!:
What is not kings english ? I am trying what 6 degrees do in max. power RPM....Isn't that what I asked ? Oldhead
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oldhead
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Re: Going to a different cam

Post by oldhead » Sun Nov 11, 2018 10:05 pm

GARY C wrote:
Sun Nov 11, 2018 6:29 pm
I would have guessed 200 to 250rpm but you not going to find many people posting on line that have ever dyno tested a 6 degree cam change, me included.
If you changed any degrees how many RPM the maxium power RPM go up???? Oldhead
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Re: Going to a different cam

Post by GARY C » Mon Nov 12, 2018 2:50 am

oldhead wrote:
Sun Nov 11, 2018 10:05 pm
GARY C wrote:
Sun Nov 11, 2018 6:29 pm
I would have guessed 200 to 250rpm but you not going to find many people posting on line that have ever dyno tested a 6 degree cam change, me included.
If you changed any degrees how many RPM the maxium power RPM go up???? Oldhead
I have never tested that, for what it's worth, here is a test with a 222, a 234 and a 248.
https://youtu.be/rJNsZrNz_Y4?t=452
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ProPower engines
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Re: Going to a different cam

Post by ProPower engines » Mon Nov 12, 2018 3:05 am

oldhead wrote:
Thu Nov 08, 2018 8:42 pm
I was wondering if I added 6 more degrees or dropped 6 how much RPM would max. HP. would change? SBC-400 8 to 1 comp,300-235 heads,800 cfm carb,248-260 at .050 114 cl.,making 470 hp at 6250 rpm.Unblown of course...I WANT TO THANK THE GUYS THAT ANSWERED LAST TIME. OLDHEAD
If this is a forced induction engine ( blown) it seems to me you want to change the LSA to reduce the overlap.
if the overlap is lets say 100 degrees and you reduce it to 75 degrees you will not loose so much cylinder pressure during the overlap period of the cam timing. While it is possible to increase or decrease the cam timing 6 degrees and keep the same LSA you may just make things worse not better or no change at all.

Based on the current cam spec you have above I would try something with maybe 116 or 117 just to try to keep what you pumped in there to stay there.

That said if it is not forced induction then I would tighten up the LSA rather then adding more @50 timing or reducing same.
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