Proper carb configuration for 460?
#1
Proper carb configuration for 460?
Hello!
I usually visit the 70's dentside thread, but I wanted to branch out and talk to the engine specific side on this one.
We're trying to dial in this carb. Right now I bought and installed a 1406 600cfm Edelbrock performer carb and I am not very happy with it, per suggestion of my engine guy who knows volumetric efficiency. I have heard the early 460 came stock with some kind of 605cfm carb. So now we are playing around with it because we bored mine .60 over and the throttle response doesn't feel right. It feels like it's stammering a bit and kind of sluggish when I get on it. I am just learning how to calibrate these things, so I am just curious what configuration you guys run. I'm thinking I might jet up from the stock configuration which is main jet (.098) and secondary (.095), to maybe a (.113), (.107). And of course play around with the springs and metering rods, which we already put the silver springs on. I don't know, just looking for some experience on these configurations. It just doesn't feel right, like it's being held back. There isn't a smooth, powerful acceleration that I am looking to achieve here. Any suggestion would be awesome!
A separate issue is something seems to be sticking in the throttle linkage, causing it to stick at a higher idle sometimes, just over 1000rpm. We have it set lower, at around 700 but sometimes it will stick and I'm wondering if I should get a dual return spring setup, or if the problem is in the linkage down by the floor where the rod exits the cab. Is there some kind of bearing in there that might be worn out? I tried some penetrating blaster into that area but it didn't help. Sometimes I have to kick my toe up under the pedal and pull back to get it to return to the correct idle which I won't be able to tolerate for much longer.
I usually visit the 70's dentside thread, but I wanted to branch out and talk to the engine specific side on this one.
We're trying to dial in this carb. Right now I bought and installed a 1406 600cfm Edelbrock performer carb and I am not very happy with it, per suggestion of my engine guy who knows volumetric efficiency. I have heard the early 460 came stock with some kind of 605cfm carb. So now we are playing around with it because we bored mine .60 over and the throttle response doesn't feel right. It feels like it's stammering a bit and kind of sluggish when I get on it. I am just learning how to calibrate these things, so I am just curious what configuration you guys run. I'm thinking I might jet up from the stock configuration which is main jet (.098) and secondary (.095), to maybe a (.113), (.107). And of course play around with the springs and metering rods, which we already put the silver springs on. I don't know, just looking for some experience on these configurations. It just doesn't feel right, like it's being held back. There isn't a smooth, powerful acceleration that I am looking to achieve here. Any suggestion would be awesome!
A separate issue is something seems to be sticking in the throttle linkage, causing it to stick at a higher idle sometimes, just over 1000rpm. We have it set lower, at around 700 but sometimes it will stick and I'm wondering if I should get a dual return spring setup, or if the problem is in the linkage down by the floor where the rod exits the cab. Is there some kind of bearing in there that might be worn out? I tried some penetrating blaster into that area but it didn't help. Sometimes I have to kick my toe up under the pedal and pull back to get it to return to the correct idle which I won't be able to tolerate for much longer.
#2
If it's stumbling when you get on it you could try adjusting the accelerator pump lever to make it squirt more fuel with throttle input. I don't know what jets to tell you to run, each engine is different depending on elevation, cam, compression ratio, etc. Pull the plugs and see how they look. If it's lean it'll usually stumble or buck, if it's rich it'll blow some black smoke and just not seem very crisp or snappy. As far as the throttle not returning to idle, make sure the choke is working properly (opening), and just give all the linkage a thorough inspection.
#3
Thank you. I noticed that Edelbrock states that their 750cfm is dialed for both Chevy 454 and the Ford 460, but that's with their manifold. I'm not running an Edelbrock performer manifold(does it make that much of a difference?). but I might try that jet/rod configuration and see what happens. I haven't been able to get a day to run this thing, it's been icy and sloppy up here. There's no dyno or quarter mile so I have to dial it in on a stretch of old highway. I will go through the linkage, I did buy a little bracket with dual return springs instead of the stock one spring gig, maybe that will help the idle return.
#4
I hate to say it, but I went through this exact same thing with my 460. But I was never able to get the 600 CFM Edelbrock tuned to where I was happy, even at several stages rich. It just never seemed to produce the power I expected.
Now I run a 750 Holley vacuum secondary and it's been great. It's actually jetted one stage lean in the primaries, and using a 5.5Hg power valve.
Now I run a 750 Holley vacuum secondary and it's been great. It's actually jetted one stage lean in the primaries, and using a 5.5Hg power valve.
#5
I hate to say it, but I went through this exact same thing with my 460. But I was never able to get the 600 CFM Edelbrock tuned to where I was happy, even at several stages rich. It just never seemed to produce the power I expected.
Now I run a 750 Holley vacuum secondary and it's been great. It's actually jetted one stage lean in the primaries, and using a 5.5Hg power valve.
Now I run a 750 Holley vacuum secondary and it's been great. It's actually jetted one stage lean in the primaries, and using a 5.5Hg power valve.
I see. I am new to messing around with these carburetors, but can't I just jet up and have the exact same thing as a 750? I mean, the bodies appear to be the same with the electric choke, I just have to jet up to the same configuration that the 750 contains, it has all the specs in the manual, what combos to run rich/lean, at wide open, etc. So I'm thinking I just jet up to the next level and just keep trying it out. If it's firing out the tailpipes I'm going too much. I've had people tell me that it's all just trial and error when you rebuild one of these old engines, there might even be a better configuration for your Holley and you might be missing out on some power or economy. But it's all about making time to figure it out, that's where it's difficult for me. haha
#6
Check your timing. Make sure your vacuum advance is working. My base timing is about 12* plus I'm running manifold vacuum (through a blue vacuum restrictor). With 12* initial, plus another 12* vacuum advance, I'm somewhere like 24* advance at idle which sounds horribly wrong... but works great.
12* initial advance versus 8* initial advice made a surprising improvement in power and economy. Just don't advance the timing so far that it starts pinging or kicking back on the starter.
The balancers have also been known to slip as the center rubber part deteriorates and a slipped balancer will throw off your timing marks.
Before I switched to manifold vacuum I had a little stumble at initial tip in but with manifold vacuum it's sharp off the line.
I'm running the stock 4180 vac secondary carb which I think is 650 cfm.
12* initial advance versus 8* initial advice made a surprising improvement in power and economy. Just don't advance the timing so far that it starts pinging or kicking back on the starter.
The balancers have also been known to slip as the center rubber part deteriorates and a slipped balancer will throw off your timing marks.
Before I switched to manifold vacuum I had a little stumble at initial tip in but with manifold vacuum it's sharp off the line.
I'm running the stock 4180 vac secondary carb which I think is 650 cfm.
#7
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#8
I see. I am new to messing around with these carburetors, but can't I just jet up and have the exact same thing as a 750? I mean, the bodies appear to be the same with the electric choke, I just have to jet up to the same configuration that the 750 contains, it has all the specs in the manual, what combos to run rich/lean, at wide open, etc. So I'm thinking I just jet up to the next level and just keep trying it out. If it's firing out the tailpipes I'm going too much. I've had people tell me that it's all just trial and error when you rebuild one of these old engines, there might even be a better configuration for your Holley and you might be missing out on some power or economy. But it's all about making time to figure it out, that's where it's difficult for me. haha
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