EFI Intake thoughts/ramblings for a 440

[jayb]

Hmm, now you got me thinking. And that's usually trouble.
I do have two hoods.

Cut one LOL!  When I get one of those mounted up on an engine I'll take some measurements for you.

[newfalconowner]

could always put a boss 429 type scoop on it 

[newfalconowner]

my tunnel ram'd efi doesn't stick out much over my hood so Im making a scoop

[CaptCobrajet]

I have one like the link Jay posted.....not complete yet, but Trick Flow has some different options for upper plenums, depending on your combo.  I like the long runners, even length, nicer plenum than a "carb flange" manifold.....JMO.

[Joe-JDC]

Have both tops available, and I have new fuel rails for 351W/5.0 HO, and I will check for fit Monday.  I also have a NIB 75mm throttle body, but you may want something larger like the Lightning, or custom up to 110mm.  I personally don't think that there is a whole lot to be gained with the larger throttle bodies until you start pressurizing the engine with lots of boost >14psi.  The 75mm will let you start and calibrate quite well, and a vacuum gage will let you know if you need more Throttle Body just like a carb vacuum reading.   Joe-JDC

[Joey120373]

I am eagerly waiting for someone to test this combo too.
The long runner trick flow manifold is what I hope to run on my engine.
It's going into a 1971 F250, hope it clears the hood......

I can't imagine that it would hurt HP and tourque, for a reasonable street motor anyway.

According to accufab, a 75mm throttle body will flow 920cfm
And the 90mm will flow 1369cfm. That should be plenty for most mortals.

I also agree that going to big on a TB is generally a bad idea, at least for a street driven vehicle.
Kinda like cylinder heads, usually it's best to get the smallest one that will still flow the amount of air you need.

[cammerfe]

But, on the other hand, Ford did some good Trans-Am work with a pair of 4500s on a Boss 302. Whooda thunk?

KS

[Joey120373]

Well yea . If ya want all the hp you can get from a combo, go big or stay home!

I was thinking more on the lines of every day drivability, a big honkin 105mm TB on a shag nasty motor is going to be tricky trying put through the drive through. At 5-10% throttle, the big tb is going to let way more air into the motor than a 75mm to at the same throttle opening.
But if your goal is that last tenth, hog that 105 out and maybe use 2 of them....

[cammerfe]

Back yonder I had one of the 'two-big-Holley' Boss 302 manifolds but traded it off in a complicated swap. I never drove a car with that particular combo. I don't know about low-speed drivability, but please note that Trans-Am was a road-racing series. And there is a small progressive cam arrangement that goes on a throttle shaft that's supposed to make small throttle openings more manageable.

KS

[ericwevans]

Back yonder I had one of the 'two-big-Holley' Boss 302 manifolds but traded it off in a complicated swap. I never drove a car with that particular combo. I don't know about low-speed drivability, but please note that Trans-Am was a road-racing series. And there is a small progressive cam arrangement that goes on a throttle shaft that's supposed to make small throttle openings more manageable.

KS

I've been thinking about progressive linkages with dual quad setups lately too and came to the same conclusion that the dual quad has to be more drivable.  Dual 500 cfm carbs vs my current 750 cfm, at low throttle settings I am only operating a set of 250 cfm butterflies vs. the 375 cfm butterflies on the single carb.  Next step is to put it into practice and see how it works.   

[Russ67Scode]

Here is my Victor with the FAST port injected system. Lots of wires, but a fun project
Starts right up after sitting for 2weeks and idles !

[cammerfe]

For some reason, photos here recently have been 'gi-normous'

KS

[Barry_R]

The dual 4500s on the Boss 302 were an IR system.  You cannot size an IR carb the same as a plenum deal since the cylinder only "sees" a single barrel.

And two 500 cfm carbs are only appropriate for lawn mower size engines.  Edelbrock 500s are only useful as paperweights - and they probably suck at that too...

[gdaddy01]

I like your comments on the edels .  what would be close on a stock '61 390 with a 270s cam , edel two four single plane , 4 speed 3:00 gear , mostly for highway driveing ?

[Barry_R]

The Edelbrock 600s and 750s work just fine.

The darn 500 has the single worst booster design and calibration I have ever seen on a production carburetor intentionally sold to the public.  It was dead pig rich at any point in the curve above idle, and if you physically jammed the fattest metering rods down into the smallest jet it would only go non-linear - lean at one end of the curve while remaining blubbering fat elsewhere.  The most cost effective fix involves four fasteners and a garbage bag....

A close second would be the cheap Holley mechanical 450s with no secondary pump.  Guys in Holley engineering referred to those as "flamethrowers" back when I was working there.... same kind of application, similar bad (but different) results.