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Originally Posted by JimV
(Post 2128205)
I've had most success porting the intake to a height of 2.1" by 1.750. With a 2.25 intake valve they will flow low/mid 360 cfm. With the small port opening, I dont think the 2.300 is being utilized. I'm a little consern when you say the ex ports have been port matched. Exhaust ports are sensitive in the bowls and the port floors out to the flange. You can hurt airfow if not ported correctly. Overall the heads will work good with some porting.
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If you choose to raise the boost, you are sacrificing reliability.
The cam IMO is way too fat in its centerline and you are blowing off your pressure through the duration. Nice cam.. wrong application. Like JimV said , basically you are needing to open the exhaust ports, now to compensate.... and that compensation is for the cam. IMO If you want to hear a similiar application , email me at this name on AOL. Would be glad to talk. |
Originally Posted by JimV
(Post 2128205)
I've had most success porting the intake to a height of 2.1" by 1.750. With a 2.25 intake valve they will flow low/mid 360 cfm. With the small port opening, I dont think the 2.300 is being utilized. I'm a little consern when you say the ex ports have been port matched. Exhaust ports are sensitive in the bowls and the port floors out to the flange. You can hurt airfow if not ported correctly. Overall the heads will work good with some porting.
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Your heads are holding you back a ton!!! With a Supercharged application, a rect. port design is the way to go. I would use a Dart Pro 1 or Brodix BB 2 - plus CNC head on your application with a runner volume of 320. I built a 468 with a B&M 420 with a superchiller same 2 X 750 Holley double pumper with mech. roller camshaft. With 8-9 lbs of boost engine made 875 HP at 6000 RPM. Your camshaft is not "TOO BIG" either. I ran a .672/.672 lift 252/257 @ .050 on a 112 lobe seperation.Degreed cam on a 108 intake centerline.8.75:1 compression ratio, 93 octane fuel . Engine still had power left with timing very conservative. The engine went into a 25' Baja from Michigan. Wild Ride!
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Originally Posted by ghittner
(Post 2129225)
JimV, they have only been port matched to a Stainless Marine manifold opening..... Very little as it was almost dead on to begin with...We are talking about the oval port heads that I have when you are opening them up to 2.1x1.75 ??? correct???
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Originally Posted by JimV
(Post 2129387)
Yes, grind the material off the roof of the port. This will help but to make it right it needs a good ex port and some chamber work.
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Originally Posted by mrhorsepower1
(Post 2129342)
Your heads are holding you back a ton!!! With a Supercharged application, a rect. port design is the way to go. I would use a Dart Pro 1 or Brodix BB 2 - plus CNC head on your application with a runner volume of 320. I built a 468 with a B&M 420 with a superchiller same 2 X 750 Holley double pumper with mech. roller camshaft. With 8-9 lbs of boost engine made 875 HP at 6000 RPM. Your camshaft is not "TOO BIG" either. I ran a .672/.672 lift 252/257 @ .050 on a 112 lobe seperation. Engine still had power left with timing very conservative.
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Crane Mech.Roller CHB 290009 Grind # 290-295-12 R IG
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Originally Posted by ghittner
(Post 2129612)
I thought the Merlins were a good, raised exhaust port and that's why I decided on them for my normally aspirated motor. Is that not the case???
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Originally Posted by ghittner
(Post 2126961)
Explain please.
You have the best input I've seen on heads with some real experts. The cam is too big, big is not better, a 232/[email protected] on 112 would be max if I was doing it, Maybe a little smaller, but let these guys offer suggestiond with there heads. LH |
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