Inliners International Forums General Discussion Hi Performance Edelbrock Primaries?

I was just wondering if anyone has noticed a difference between mounting the primaries inboard or outboard on their inline? Or, if there is a "correct" way to do it. The engine is a 250, and the carb is an Edelbrock 600cfm (1406).

Right now I have the primaries mounted inboard, but I have to fab up some new linkage, so I thought I'd ask. Thanks. John

I've been told by some veteran Inliners that the main thing is to have the carb "Inline" as opposed to V8 style, but others have reported that is doesn't seem to make a lot of difference in how the engine actually runs... As far as inboard vs outboard with the primaries, I doubt that matters much either, but it would seem that attaching linkage at the rear of the carb, closer to the head, could get pretty tricky.

Thanks Jack. I'm trying to rework my carb linkage right now, hopefully for the last time, and figured I'd ask to make sure. I'm trying to fab up some linkage instead of the cable, or a combination of both. Thanks. John

I'm running a 500 Edelbrock on my 250 using an Offy manifold. The carb is sideways with the primaries inboard toward the head. I had to use a 1/2" thick 4 hole spacer to raise the carb enough so the throttle linkage would clear the manifold. I am using a Lokar throttle cable with a nice gentle bend around the outside of the carb to the throttle arm. The brackets to mount and support the cable I had to make and actually used the original Chevy 6 cylinder bellcranks that were on the intake manifold. A little cutting and redrilling, a little welding, a little black paint and they did the job. These newly refabbed brackets now mount on the carb flanges under the stud nuts.

As for how or why the carb sits sideways all I can say is like Jack mentioned - other Inliners claimed thats the way it ought to be and after thinking about it it made sense as far as semi even fuel distribution instead of the primaries appearing to favor the front 3 cylinders. Whether or not it really matters I can't say; but from my experience with now over 9000 miles on the engine I can tell you it runs perfectly around town, on the highway for 13 hours at a time, and for the occaisional stop light drags when it kicks V8 butt. It's not broke so I have no intention of fixing it.

Mike
37 Chevy, 250 / Muncie 4 speed

Mike,

I'm running the same intake and carb on a .060 over 292 with a mild cam. I didn't change jets or metering rods - it's basically running as is out of the box. It seems to be just a tad bit much for my engine, what did you change to get it run right with your smaller 250?

My performance is great, my plugs are just a little black and you can see a little exhaust smoke on startup and re-startups. Maybe I can tune mine like yours and see what happens. What kind of headwork did you do and what specs are the cam you're running?

-magic mike-

Mike G-- Any chance of pictures of those brackets?

I know the carb has to be perpedicular to the engine, but I was just wondering if location of the primaries mattered. As in, if the primaries faced the engine, or if the faced the wheel well. I'm thinking I may swap it to facing the wheel well and see what happens. Who knows.

My linkage is part cable and part stock rod, but I'm thinking about going with a non-cable setup. We'll see. Thanks. John

For Magic Mike: my 250 is .030 overbore with stock type pistons and carefully clearanced and balanced. The head has had the bolt bosses removed but no lumps installed, fully ported and has a 1.94 / 1.50 valve set up. It is also milled .080". Running a 214 @.050" Comp Cam with Crane Gold roller rockers. Clifford street rod tubular headers with 2 inch pipes into short stock type mufflers to keep the sharp exhaust crack noise bearable. Running a Chevy HEI coil in cap distrib but it has all the innards and the coil replaced with MSD items. R44XLS plugs gapped at .045" and Taylor Spiro Pro wires.

Right now I don't have the jet and rod numbers in front of me but I'll post them tomorrow for you.

I first ran this 500 carb on a 305 V thingy and found it to be too rich out of the box for the 305 which has a similar mild cam and full dual exhaust so a quick guess would be thats why it is too rich for your 292. In fact we ran it for a while on my sons 350 Chevy V8 that has a 224 duration cam and it still needed a minor rod change. They take a little time and patience to tune and after installing 5 or 6 in different sizes on various engines I can tell you that I haven't installed one yet that was a perfect set up right out of the box. No universal carb is.

For John: I don't have a digital cam or scanner that works so I can't post a pic here for you or else I would. I don't mind taking a regular 35mm pic and snail mailing it to you if that works for you. All the bracket is that holds the throttle cable is basically an L shape with the vertical leg twisted 90 degrees for the cable housing fitting to pass through. The base of the L simnply slips over the carb mounting stud before you add the lockwasher and nut. A second L bracket without the twist is welded upside down to the base of the upper one. This keeps the whole thing from turning by resting against the base of the carb and the dropped down leg of the L has a hole for the throttle return springs.

Picture an L with a 7 underneath it, the base of the L and top of the 7 on top of each other, welded together and then drilled for the carb stud. Sort of ends up looking like a T on its side except for the twist in the upper part.

If you want a pic or two just email me with your address. Add Inliners to the subject line as I have a killer spam blocker that lets nothing through!

Mike bibb31@earthlink.net

For Magic Mike:

Here is the set up I am running in my carb.
Pri jets .086, Sec jets .095, plain colored springs in the metering pistons, .067 x .055 rods.
I've also tuned with .068 x .052 rods and .070 x .052 rods but found what is in it now gives me the best overall results on this particular vehicle. The larger stepped cruise diameters tended to be a bit lean in cooler weather and at the same time the smaller power diameters were a little too rich in hot weather.

Not all of these rods and jets are part of the tuning kit you can buy for the 500 and some will have to be bought individually so shelling out $46 for a tune kit is a waste in my opinion. Check your Edelbrock parts list for rods and tuning parts.

You could use my set up as a start and see how it goes from there?

Trying to get a read on your plugs is not going to tell you much if you are running any sort of an HEI or CD ignition system. Those ignitors can keep all but the most severe loading up cleaned off the plugs. Driveability, response, and exhaust smoke will tell the tale if you take your time and don't have access to a dyno.


Good luck, Mike

Mike G,

Your information is priceless. Thanks a lot!

-magic mike-