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RHS 235cc SBC head

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RHS 235cc SBC head

Postby Grits & Gravy » Sun Sep 16, 2007 12:45 am

What kind of flow can these make with a max port?
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Re: RHS 235cc SBC head

Postby rookie » Sun Sep 16, 2007 11:06 pm

Grits & Gravy wrote:What kind of flow can these make with a max port?

Hear is RHS flow sheet, pm me if your interested, I can probably save you some $ on these.
http://racingheadservice.com/Information/Technical/Heads/SmallBlockChevy-Heads.asp

Depending on your cubic inches a ported 220 head will flow about as well and may work better for your application.
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Postby bigjimzlll » Sun Sep 16, 2007 11:37 pm

Why do they flow them at 4.20" bore? Besides it inflates the numbers?
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Postby rookie » Mon Sep 17, 2007 12:32 am

I'm not sure why they do that most people I know, including myself flow on a 4.125 bore for small block, most test I've seen show very little to no difference from a 4.00 to a 4.125 bore.

With that said I have yet to see any head flow the same as advertised, most advertised flow# are done in a controlled environment on the first head developed and casting variations plus atmosphere, temp, elevation, all effect flow even CNC heads rarely flow what is advertised.
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Postby Competition Engines » Mon Sep 17, 2007 8:15 am

Here are flow numbers off our SF-600 on a 4.030" bore. This is out of the box with 2.080 x 1.600 tit. valves.

.200 113 91 80%
.300 161 119 73%
.400 209 141 67%
.500 248 157 63%
.600 281 166 59%
.700 293 173 59%

This was a budget dirt open-wheel modified engine. I put them on a 355 with a roller cam on alcohol. The engine runs pretty. You need bigger ports with alcohol. Once again, this shows most companies don't publish acccurate flow numbers.
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Re: RHS 235cc SBC head

Postby randy331 » Mon Sep 17, 2007 8:30 am

rookie wrote:
Grits & Gravy wrote:What kind of flow can these make with a max port?

Hear is RHS flow sheet, pm me if your interested, I can probably save you some $ on these.
http://racingheadservice.com/Information/Technical/Heads/SmallBlockChevy-Heads.asp

Depending on your cubic inches a ported 220 head will flow about as well and may work better for your application.


Are the flow #s on the 235cc head with 2.02" valve or 2.08" valve?
On the page above the flow graph, it says 2.02, when you go to the tech sheet, it says 2.08. What do the heads come with?
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Postby rookie » Mon Sep 17, 2007 6:13 pm

The 235cc heads come with 2.08 intake valve.
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