I read an article by David Vizard about the large torque increase he found when testing indivdual runner (IR) manifolds, basically a single throttle blade for each intake port. This got me wondering if converting an old Hilborn IR manifold to EFI would provide torque increases and drivability that would justify the cost. Anyone have any experience at this?

Bill

I dunno, you could almost afford a RamJet 502 for what they want for the setup straight from Hilborn (http://www.hilborninjection.com/product.asp?Id=56&CatId=37) :eek:

Darren

I was hot for a Man-I-Fre (sp?) manifold and 4 Webers (2v carbs) for a while after reading Vizard. I saw a picture of this setup in a 57 Chevy and it was gorgeous. Cost is extremely high and tuning is a major chore. I think I'll stick with a single 4 barrel.

http://www.camcojb.com/superformancesmall/cobramotor.jpg

I loved mine. Easy to tune and held the tune when it was done. It is pricey though.

Jody

Nice looking motor Jody, that's GOT to drive those FORD purists nuts smile.gif

Originally posted by d1_bradley:
Nice looking motor Jody, that's GOT to drive those FORD purists nuts smile.gif Yes it did! I built two of those cars; one a small block and one a big block, both Chevy's! :D

Jody

Force Fuel injection makes a stack EFI setup.

www.Force-efi.com (http://www.Force-efi.com)

I spoke with a guy who had a BB in his '57 Chevy and he had swapped from a dual-four setup to a Hilborn injection unit. Yes, they are pricey. However, he dynoed the combo afterward and picked up a noticeable amount in both the HP and TQ areas. I'm sorry that I can't remember the gain.

The cool thing was that fuel consumption didn't go down one bit, so it was making more power with the same amount of fuel. Pretty cool stuff.

He also told me that the 2x4 intake took a lot of dyno time to get tuned in and the Hilborn unit only took about an hour.

I'd absolutely love to have a setup like that, but I want to figure out how to adapt it to a Cadillac 500! Dare to dream...

I'm shocked by the prices! I wonder how much is hardware and how much is labor. Would love to see a magazine article on that.

Here's my tale......
In the early part of the '80s, I worked with Peter Guild of ProMotor Engineering on a March road-race car, sponsored by Red Lobster. We built a 358, with Lucas Mech Timed injection, and a SB312/318R6 roller cam(276/282 at .050, .592/.609 valve lift). It was tuned to make about 550 BHP, not highly stressed at all. It finished 6th in the 24 Hours of Daytona, which led Red Lobster to put a lot more money into the car.
Peter then built another engine, and put a Bosch EFI on it, using the McKay individual-runner manifold with 2.3" throttles. We tested on his 358 mule engine. The mule with 750 Holley, Victor Jr, and my old favorite SB288/296R6, would always deliver about 440 ftlbs at 4000, 470 ftlbs at 5250, and 576 BHP at 7200, always. Using the Bosch/McKay combo and the same SB288/296R6 cam, we got 520 ftlbs at 5250, and a bigger jump at 4000. At 7200 we had 576 BHP. I believe we had injection timed to occur right as, or slightly after, exhaust valve closing.
We figured out that high-speed power was a function of intake-port volume and cam size, but the bottom end was helped by a cleaner, unpolluted charge, with no possible fuel loss out the exhaust runner. So I designed another cam...
The new cam was a SB318/318R8, 282/282 at .050, .609/.609 valve lift. From 4400 rpm on up, it had MORE torque than my SB288/296R6 with the 750. Peak power was 620 BHP at 7500.
The car was now so fast that, after 4 hours in the race, the driver totalled it.......
BTW, individual-runner manifolds are EXTREMELY sensitive to runner length.

UDHarold

Harold,

what I noticed with mine was that it really tamed the camshaft. The other thing to remember is that you do not have a plenum to "borrow" from, so some setups may have too small of throttle blades. My 406 was somewhat restricted with the 2 3/16" throttle blades that came on that system. The heads actually out-flowed the throttle blades/manifold by 30 cfm or so. It still ran good and picked up a bunch of lower end torque as compared to a single plane/4-barrel throttle body setup I had on there before that. I can see how an IR-specific camshaft could take advantage of the setup.

Jody

Jody,

Some racing associations use the 2-3/16" Hilborns as RESTRICTORS for 355 Sprints, so they are definitely a little 'tight' on a 406...
I would use a 2-7/16" or larger on a 406. With SEFI and tuning of injection-point, you can use a bigger-duration cam and a wider-LSA, for more torque and power everywhere.

UDHarold

The cam was a .625 lift, 264 @ .050 with a 110 lsa. Not my choice but it made over 480 rwhp with 10:1 compression so I was not complaining! Heads were fully ported Dart Iron Eagle 230's.

Jody

Does anyone know the appropriate throttle size for a 460 inch Chevy? I saw one on Ebay with 2 3/16" bores which I previoulsly thought was huge. Now I'm not sure.

You sure it wasn't 2 7/16"? 2 3/16" would be small on a big block, and would definitely limit power.

Jody