[SD455DJ]

I have a 461 (400 block with 4.25” crank/4.15” bore) that has 6X8 heads that were given the CNC porting job at SD Performance (2010?) and I never received the flow sheets with the car that the engine was in. I think the CNC porting is to provide around 255 cfm (+/-) on the intakes and 200 cfm (+/-) on the exhaust, but at what lifts?. I'd love to know more what these heads can do.

Does anyone have flow data sheets they could post on similar SD CNC heads? Thanks!

Dennis

[ponjohn]

This might help.

[TB1]

Here another sample mine were done in 2018.


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[SD455DJ]

Originally Posted by ponjohn

This might help.

Thank you Ponjohn! I believe 1.77 exhaust valves were installed as a part of the package? I never took the heads off to confirm. The engine has a Bullet hft cam 231/239 @ .050 .485"/.507" lift w/ 1.5 rockers and 112 lsa.

Dennis

[SD455DJ]

Originally Posted by TB1

Here another sample mine were done in 2018.


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Thanks TB1! The CNC program sure made the flows consistent.

Dennis

[tom s]

On Stans site pretty much shows Daves 260 CNC are at 600 lift and are usually in the higher 250s range no matter what D port iron head.Tom

[SD455DJ]

Originally Posted by tom s

On Stans site pretty much shows Daves 260 CNC are at 600 lift and are usually in the higher 250s range no matter what D port iron head.Tom

Hey Tom! I'll have to check Stan's site out. Thanks! (Ever find a worthy Cosworth?)

Dennis

[pastry_chef]

Originally Posted by SD455DJ

I believe 1.77 exhaust valves were installed as a part of the package?

Funny those two example images are cropped in just a manner to hide the exhaust valve sizes.. even on an angle .. lol

[tom s]

I gave up on another car until I get my intake manifold deal done!Tom

[TB1]

Originally Posted by pastry_chef

Funny those two example images are cropped in just a manner to hide the exhaust valve sizes.. even on an angle .. lol

I wasn’t trying to hide anything other than my name on the print out. Here’s the full sheet if it matters?


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[steve25]

Judging by Dave’s exh numbers hitting 200 cfm by .500” lift they must be reworked with 1.77” valves .

[SD455DJ]

Originally Posted by steve25

Judging by Dave’s exh numbers hitting 200 cfm by .500” lift they must be reworked with 1.77” valves .

Sure looks like 1.77's were installed and I believe his old ad on his website (now removed since he doesn't port iron heads any longer) said as much. I appreciate the pics of your flow sheets and wish I had mine. I'll be asking the previous owner that built the engine I he has it still.

Do you know what level this SD ported iron intake is? SD has 3 levels:

$175.00 CNC plenum + hand finish

$275.00 CNC plenum + hand finish + port matched runners to std. intake gasket

$375.00 CNC plenum + CNC port runners + hand finished (we've made over 600hp with these modifications!!!)

I'm thinking these are the 2nd level ($275) with the CNC plenum and port matched runners to std. intake manifold gaskets.

Thanks again! Dennis

[steve25]

It looks like level 3 since the port match is to RA4 gasket size, not standard D port.

[SD455DJ]

Originally Posted by steve25

It looks like level 3 since the port match is to RA4 gasket size, not standard D port.

Thanks Steve...I'll have to take a closer look at them when I get the chance and lay RAIV and std. gaskets on the ports.

Dennis

[78w72]

definitely RA4 ports on that intake, stage 3.

[grandam1979]

Wow that’s a nice intake looks like stage 3 to me

[SD455DJ]

Originally Posted by grandam1979

Wow that’s a nice intake looks like stage 3 to me

LOL! I should have just texted you about this. I never knew there was a difference in the iron intake modifications until I was looking into the head flow numbers on SD Performances website. So, this intake is the Stage 3...COOL! And thanks ga1979 for selling it to me! It's going to be installed on the 461 with the SD CNC 6X8 heads this summer replacing a stock iron intake...and a 800 cfm Q-jet.

Dennis

[78w72]

Originally Posted by SD455DJ

LOL! I should have just texted you about this. I never knew there was a difference in the iron intake modifications until I was looking into the head flow numbers on SD Performances website. So, this intake is the Stage 3...COOL! And thanks ga1979 for selling it to me! It's going to be installed on the 461 with the SD CNC 6X8 heads this summer replacing a stock iron intake...and a 800 cfm Q-jet.

Dennis

thats a great intake, i had an iron one on my 467 500+hp with a Q-jet & it ran consistent low 11's. upgraded to a aluminum HO with SD's stage 3 porting now.

[SD455DJ]

Here's the SD CNC ported intake with RAIV/455HO/SD455 intake gaskets laid on it for comparison to the ports and some close-ups of the CNC work.

Dennis

[scott70]

I port matched my stock iron 70 intake to a RA4 gasket and there wasnt much material left at the top(roof) of the port. I bet I only had about a 1/8" max. It seals though,,,I ground right to the edge of the gasket.