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Old 08-23-2019, 02:08 PM
AIR RAM AIR RAM is offline
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Join Date: Sep 2002
Location: Homestead FL
Posts: 412
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Quote:
Originally Posted by Steve C. View Post
When I converted to fuel injection on my current 505 we used a Holley HP EFI Universal kit, p/n 550-500

https://www.holley.com/products/fuel.../parts/550-500

Holley p/n 522-488 48 lb/hr fuel injectors
Holley p/n 565-107 Dual Sync distributor

For the intake manifold we used a old style 4500 Victor intake that I had on hand. It was previously runner blended and port matched to my cylinder heads. We outsourced the intake to have bungs welded on for the fuel injectors and the FI rails mounted. In order to fit the 4150 style throttle body to the intake we used a Brodix HV300 4500 to 4150 carburetor adapter. However the adapter was modified, it was cut down and blended for a smooth transition into the intake plenum/runners. With the adapter modified and the shorter throttle body there was no reduction in hood clearance. I use a small diameter K&N air filter that fits up inside the shaker scoop molded onto my fiberglass hood.

The previous 4150 Victor intake with the carb pad milled 0.650" was not used for the FI project. Our dyno testing indicated by milling the intake it lost about 8-10 hp at peak power rpm. With it and my modified HP950 carb the engine made 660 hp at 5900/7000 rpm. No testing was done after the change to fuel injection but I suggest there was no significant loss in power.


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It would be interesting to see how an set up would react to the same intake both before and after milling and fuel injection all else equal.

I guess the test would need to be (and unlikely to ever happen)

Intake un-milled - CARB vs Fuel injected
Intake Milled - Carb vs Fuel injected.


I would think that the fuel injection set up would not be as finicky to the placement height of the throttle body vs a carburetor which operation is in direct relation to the air flow passing through it and the air+fuel within the intake.... The Carb will respond with changes in spacing however I dont believe a "throttle body" which only flows air is as responsive to the throttle body height as it is to velocity within the intake runners.

So I personally feel that a fuel injected engine can get away with a lower profile single plane intake manifold (and fit under lower hoods) than a Carb engine and make the same if not more power than a carb with ideal spacing that needs a taller hood to run.

I ended up going with the Northwind intake for its lower profile and EDL fuel rails... Hopefully it will work well.

And I could be way off on the mark as well...Ive been wrong on occasion.

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