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mahony.2469

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Cam selection need help
« on: July 29, 2022, 07:28:30 pm »
I have a sbc with iron heads and pretty much stock with Edelbrock logs and want to cam it as much as possible before any water revision issues...any input would be appreciated


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mash on it

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Re: Cam selection need help
« Reply #1 on: July 29, 2022, 10:08:48 pm »
Any idea on what year or vintage the SBC has? Casting numbers on the block and heads would also help.
Impeller size? What pump for that matter too.

Comp cams and Edelbrock have some Dyno charts on their most popular cams, which, along with an impeller chart can get you in the right direction.

Just picking a cam with huge duration isn't going to be happy with stock (severely inadequate/smog) heads, but there are some factory offerings that are better than others.

I've ran as much as 235 degrees at .050 on a big block with logs and snails, with no reversion.

For a stock 350, the Eddy performer works pretty good, .420/.442 lift, and pretty tame.
Summit has a few inexpensive offerings, like the 1103, 1104, 1105, etc.

If it's a roller block, there might be a chance at decent compression, and Melling has a few rollers available and affordable.

While logs and snails and not the best for performance,  they're not nearly as bad as single exhaust on an 85 Camero or 85 Chevy pickup.

My short recipe -
96 suburban short block, stock roller cam.
Crappy but functional swirl port heads, 64cc (Compression ratio is 9.2-9.3 to 1)
Eddy performer rpm intake and 750 Holley, GM HEl. 1.6 roller tipped steel rockers.
Sprint car headers, with water added.
A Berkeley impeller.
55 mph at 4600 rpm, all day long.
Combo is 325-330 HP. It's not a rocket, but reliable as a brick.

Dan'l
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CJ/RR 212...under construction  "Pistol Annie"

mahony.2469

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Re: Cam selection need help
« Reply #2 on: July 29, 2022, 10:50:34 pm »
My block castings are 3970014

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mahony.2469

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Re: Cam selection need help
« Reply #3 on: July 29, 2022, 10:54:55 pm »
My block was rebuilt ,3 summers ago.pretty much stock. I have a 700 Edelbrock carb   gm HEI dist. And panther pump

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Flusher

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Re: Cam selection need help
« Reply #4 on: July 30, 2022, 08:34:50 am »
Would you be prepared to do additional machine work to the heads to support additional lift?  Otherwise, I think ~.480 lift will be your limit, because of retainer-to-guide clearance.  I also think ~.480 lift will be the limit before you start experiencing piston-to-valve interference.  Regardless, you should measure before you choose a cam.

It is worth pulling a valve cover to get your head casting numbers.  Many stock small block port's flow stalls at .450 lift.

I would recommend doing this in the off season, it could turn into a can of worms, that would consume precious time on the water.
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"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

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Re: Cam selection need help
« Reply #5 on: July 30, 2022, 09:58:49 pm »
Without knowing what heads, 1104 summit with 64 cc heads,(224/224 at .050, .466/.466 lift)
1065 summit cam with 76 cc heads. (218/218 at .050, .458/.458 lift)

Compression ratio is your friend.

Both cams recommend valve springs.

Dan'l
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Re: Cam selection need help
« Reply #6 on: July 30, 2022, 10:14:36 pm »
With the Panther pump, it will absorb whatever HP you throw at it. However, because it's an axial flow pump (prop in a tube) it hits a wall at around 5,000 rpm, (think big block) and more HP becomes virtually useless. A mixed flow pump would handle the HP better.

A tight pump is better for performance, and probably would be a better place to start. Plenty of tutorials on YouTube will give you an idea on how to.

After a fresh pump, I'd add HP with a cam and if needed some good flowing heads.

Dan'l
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mahony.2469

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Re: Cam selection need help
« Reply #7 on: July 31, 2022, 11:22:14 am »
Thanks for the responses I have a better understanding of what it's going to take and should just enjoy the boat for the rest of the season.then dive into it ....


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Flusher

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Re: Cam selection need help
« Reply #8 on: July 31, 2022, 07:46:46 pm »
Thanks for the responses I have a better understanding of what it's going to take and should just enjoy the boat for the rest of the season.then dive into it ....


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There may not be a "next season"
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"I want to roll with my brother Joe" - Joe Bateman - January 29, 1950 ~ November 27, 2013

mahony.2469

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Re: Cam selection need help
« Reply #9 on: July 31, 2022, 08:13:44 pm »
Very true

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