I was determined to make the fuel inlet line with filter and gauge fit on the motor I had built. However, the issue I had was that the fuel line inlet crossed directly over the top of the coolant passage hole on the intake for the hose that would go to the heater core. I corrected this issue by shortening the inlet lines to the carb by about 1/2", which moved the inlet to the fuel line away from the coolant passage hole. The next problem I ran into was that the top of the fuel pressure gauge was making contact with the bottom of the base of the air cleaner. I tried bending the lines downward so the gauge would clear the air cleaner, but the bottom of the fuel filter housing was very close to making contact with the intake manifold. Although bending the lines down helped some, the gauge still hits the bottom of the air cleaner. Without modifying the bottom of the air cleaner, I ordered a 1/2" carb spacer and installed. With the carb spacer installed, I was able to then bend the fuel line down a little bit more to get the clearance I needed for the gauge.

So, my question is will installing this carb spacer on the Edelbrock RPM Air Gap affect idle, performance, etc. because of the issue with the open space in the divider wall? See photos so you can see what I am talking about.

Any thoughts, suggestions, feedback would be appreciated. Thanks!

 

Can you put an elbow fitting on the intake to accept the heater hose so it does not need to be routed over valve cover and can be routed around the front of head following the second heater hose around and back to the heater core.

 

Yes, with the 1/2" carb spacer in place, I can go back to the 90 degree coolant fitting. This is not an issue now. I really didn't like the idea of running the coolant hose over the top of the valve cover anyway!

My only concern Now is the gap below the carb spacer where the notch is in the divider wall of the intake and how it might affect idle, acceleration, performance, etc...

 

I wish I could answer that , but run it and see ? I would plug off the heater connection and try carb both ways ..You may also consider a diff fuel inlet tube ? ?

 

here is the PM i got from lee, has a 454 4x4 truck. he read my article in sig, and filled in the divider with a 4 hole plate. he said h got 5-6 mpg before
Now his 7000# truck can accelerate from 20 mph in 5th, without downshifting!


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Re: 4165
Sent: Sun Jan 27, 2013 9:10 pm
Sent: Sun Jan 27, 2013 9:02 pm
by lee_beazley
I am rebuilding the 4165. I, just today, finally managed to get it apart. The old gaskets were glued like epoxy. Tomorrow I'll get some gasket remover and finish cleaning. I already have the kit. I think I'll just get a new 2161 Edlebrock, when I get ready.
For now, I now have the 4777 and newly filled air gap running so well, I'm going to follow that up. It'll be good to have something to compare to anyway.
.
It's astounding what that little filler did. The mpg might still be less than I had hoped for, up to about 10 mpg ave, still not bad for a 7000lb 4X4, but this is fun and interesting. I have the idle leaned to about 14:1 AFR on the guage. It's not the smoothest idle but it's still good, at 750 rpm. Starts with the touch of the key. The smoothest idle is rich, 13.0:1. The secondary plate is almost closed and there is very little slot expposed at idle. No hesitation though.
I went down two more primary jets to 63. The AFR, cruise at 55 to 65 mph, is now 14:5 and very steady. At 65 to 75 it leans to about 15:1. Also I see it lean for a moment when I press the gas just a little from cruise. It did this even before I changed the jets. I 'm not sure if the slot should fill this gap or if I need more pump shot. I just watch the guage and don't let it go over that. I wonder if I'm not getting enough fuel through the transition slot at the higher throttle positions. Could I need to open the idle ristrictors? I'm using the pink cam, on 3, and have gone back to the .28 nozzles. Power valve is still 8.5.
It runs great. Fast warm ups, no hesitation,

I even went through the roundabout getting on the freeway, this morning, at 20 mph, with a cup of coffee in hand, and just smootly accelerated down the on ramp to 65 in 5th gear. Unreal. Thank you again. lee
Quote Matt Gruber
4165
Sent: Sat Jan 26, 2013 12:45 pm
by Matt Gruber
lee
are u rebuilding the 4165?
maybe u can make a 4 hole adapter out of wood?
2x8" could do it. I almost made one, but not enough hood clearance.
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Just to be clear, lee took 3/16" steel and drilled 4 holes in it to match the carb base. Then he welded a 1/2" piece perpendicular, in the center, to fill in the cut down divider.

 

Matt is trying to say he's not a fan of the cut down divider plenum period. I'm going to have the same set up on my 383 with a 3/8" spacer but different carb. I've yet to srart my engine so I can't elaborate on performance issues with this set up but the spacer to my understanding can only help performance. I know I'm using a 4-hole spacer on the carb side of the spacer. My question is do you use the 4-hole gasket or the square hole on the intake side. Please report back whatever you do and the results please.

 

That notch was there before you installed the spacer, and now it's still there. Why the sudden concern about it? It isn't going to have any effect that it wouldn't have had before the spacer came onto the scene.

You could fill the notch in with a gasoline resistant epoxy, I suppose. What's that stuff they use to help shape intake ports? That stuff should work just fine.


Scott

 

You want to keep both sides separated, so you would want to use a gasket on the bottom of the spacer that will seal off the center divider of the manifold against the bottom of the spacer. An open gasket will not do this, so use a 4-hole gasket.


Scott

 

it only took 1 hour to make my own out of 2/10" plywood. it is thin enough that no other gaskets are needed. just re-tighten once a week and it will fit plenty tight(if carb and manifold are flat)
plus i extended it to fit under the bowls and deflect heat.
the air-gap cut down dividers, if filled in, it must be very strong, otherwise the pulses(near the speed of sound) will knock loose anything flimsey, like 1/8" aluminum that is why lee welded 3/16" STEEL.

 

I had the same clearance issue but used the aluminum Edelbrock spacer and have no idle or performance problems

http://www.jegs.com/i/Edelbrock/350/8715/10002/-1

 

Were ya been scotty? Any ways i dont think I'd use epoxy on the off chance it came loose.

 

like Mel says the 8715 center divided usually will do the trick. It is a good idea to hold it against the bottom of the carb to verify a good seal.
Some (spread bore) have a huge center cavity that benefit by 4 holes, but many others are fine with the 8715 style.

 

Thanks for the reply. It is my understanding that the square hole gasket goes on the intake side and the 4 hole gasket goes between the carb spacer and the carb. This is how I set mine up...

 

Hey Scott, I think I get your point. Even if the carb spacer was not in place, there still would have been the "notch" below the base of the carb. By adding the spacer, I have just simply raised up the carb by 1/2" and the notch is still there. So I assume there is nothing to worry about. As far as the epoxy, I don't think I will go through the hassle of blocking off the notch. If there is some kind of noticable performance issue, I will remove the spacer and come up with another plan...

 

Hmm...wonder of the 8715 with center divider spacer that Mel is using is a better than the 4-Hole spacer? I spoke to the guys at Summit and was told I should that based on the carb I am using, I should use the 4-hole spacer. Might have to do some experimenting once I get the motor running.

 

if the summit carbs are like the 4011, and i expect they are, they have the mother of all center cavities, that thing is HUGE! the 8715 would be worthless. But not necessarily worse than that cut down divider in the RPM air-gap. I call it the "torque-gap" because it kills 50+ torque among other bad things
Notice how the 2601 performer air gap has the full divider? That would be the manifold to use with a 4 holer for outstanding manners.

 

Filled in the cut down divider & using a 4 hole 1/4 gasket.Also swapped in a mild roller cam.Idle is improved,vacuum is up to 14"hg.I can now use 4th gear on hills that I used to have to downshift to 3rd gear.Results were similar to Beejay's after he modded his intake.Low end response is much improved....
Bottom of my Summit carb:
[IMG][/IMG]
4 hole gasket spacer had to trim gasket to clear the Summit fuel bowl,should be fine with a Holley:
[IMG][/IMG]
Fuel line using Fragola push on hose:
[IMG][/IMG

 

Maybe I've missed something here but, why would you use the RPM Air Gap if the intent is to fill in the divider? Why didn't you just buy the Performer RPM with the divider intact? They are the same dimensions.

BTW, there are plenty of people who don't think that cutting the divider kills torque and some even found that it helps remove that bog in the ~2,500 RPM range.

 

What bog?
Yes, there a lot of uninformed people that think all sorts of things. And i'd be the first to bet that there are cars out there that are so far out of tune, anything is possible.
The guys with the cut down divider had no idea at the time of purchase. Guys love the looks of the 7501, and just assume it must be better. It costs more, right? So it must be better. NOT. So far, i have not seen or read about a single engine that makes more power sucking in exhaust fumes at light throttle. Guys see dyno tests that show the 7501 makes 2 or 3 more HP at ~6300 rpm and get all excited. Not shown it the loss of 50+torque in ordinary part throttle driving.

 

My logic on choosing that spacer was purely based on the thought that the spacer should conform to the design of the manifold as closely as possible. If the manifold had 4 holes I would have used a 4 hole spacer.
On the topic of the cut in the divider, why would Edelbrock have spent hugh amounts of money on developing the RPM Air Gap and then go through the additional step of making the cut in the divider if it was detrimental to making power? If I remember correctly the Chevrolet book Chevrolet Power had a modification described in their intake maniold section of the book where they added the same type of cut to an intake to increase power. Not trying to argue with what others have done to fill it in, just wanted an explanation of why Edelbrock put it there in the first place.

http://www.gmtechbooks.com/sitemap/p...4502488-83.htm