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Talk to about carb needs

///Matt

///Matt

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So the ‘68 Satellite has a 440 out of a ‘77 “something” (no idea what). I know nothing about the build specs of the motor, other than it has a “street hemi” cam. The previous owner didn’t have any more info for me than that.

Its got full headers, 2.5” dual pipes out to FM40’s at the bumper. Running an Eddy RPM and Holley 750.

The motor runs great, but lacks the power it should have. Is a 750 carb holding me back?

(I still have inspection and adjustment to do on the rest of the ignition and carb system, but I just wonder if its not enough CFM for the beast, seeing as the 6-pack does so much more)
 
In my opinion, 750 cfm is just fine on any 440 that's not stroked to 500+ cubic inches & is driven on the street. If it is a lower-compression 440 (stock '77 pistons), then you might need a different camshaft.
 
PurpleBeeper said:
In my opinion, 750 cfm is just fine on any 440 that's not stroked to 500+ cubic inches & is driven on the street. If it is a lower-compression 440 (stock '77 pistons), then you might need a different camshaft.
Click to expand...
Gotcha. Any way I can tell from a casting whether this really is a 77 motor?
 
I agree with beeper, timing also comes into play here. I poorly timed engine will run like crap. Check out what your initial and total timing are and let us know. Also get a reading on manifold vacuum at idle fully warmed up and shoot that back at us too
 
A "Street Hemi cam"(what ever that means) isn't all that hot, but it's better than any 1977 cam.
 
1. You can see the year of the block cast right into the side of it, but that only "really" maters if you still have stock pistons.
2. You "might" be able to determine if you have non-stock pistons by sticking a $25 boroscope, hooked up to your phone or laptop, into the spark plug and see if you see some TRW/Speedpro part numbers (or 030 for .030" oversize) or whatever stamped on top of the pistons.
3. I agree with Fran that a "hemi grind" (old Direct Connection "purple shaft" cam) is better than a stock '77 440 cam.
4. IF you have stock, low compression pistons I've heard that certain cams (short overlap? whiplash?) can make it perform better vs. a "regular" high performance camshaft. Some cams just work better on low compression engines....IF you still have stock pistons.
 
If you have stock low compression slugs, all that other stuff won't help much, especially the cam.
 
WileERobby said:
If you have stock low compression slugs, all that other stuff won't help much, especially the cam.
Click to expand...
Pretty sure its got stock heads on it. If I don’t want to pull the motor and swap pistons, are there affordable heads around that would up my compression and help me out? Its the wife’s daily, so any projects I get allowed to do have to take no more than a day or so.
 
PurpleBeeper said:
In my opinion, 750 cfm is just fine on any 440 that's not stroked to 500+ cubic inches & is driven on the street. If it is a lower-compression 440 (stock '77 pistons), then you might need a different camshaft.
Click to expand...

Hey PurpleBeeper: turns out the carb is a 750cfm Double Pumper with mechanical secondaries.... and at WOT on the pedal, I’m only getting around 50% throttle at the carb, and juuuuuuust barely nudging the secondaries open on the progressive linkage. Have you run into this before? The cable seems to be adjusted ok, but I think the ratio of closed-full on the pedal just doesn’t cut it for the carb. Can I change the linkage on the carb to a different ratio? Do I have to change the pedal out to get it? Or is maybe the carb just not appropriate for this combo?
 
You need to loosen the cable clamp and pull the cable back towards the firewall.
 
vintage chromoly said:
You need to loosen the cable clamp and pull the cable back towards the firewall.
Click to expand...

Are you sayying to back the threaded portion out on the cable sleeve, extracting more cable from the sleeve? Or are you saying the cable itself needs to be tighter between the pedal and carb? Because the pedal returns to the top, and even a feather touch gets the car going... but WOT doesn’t travel far enough.

DB52A8B5-9016-4316-BC96-1A1ECAB20B91.jpeg
 
That’s not a factory throttle cable.
Not sure how you can adjust that one.
 
1. In general, a 750 DOUBLE PUMPER is A LOT of carburetor for a relatively stock motor...not the end of the world, but don't expect too good of gas mileage.
2. It does look like you have a Lokar or some other aftermarket throttle cable. If there is enough "throw" in the cable (i.e. the distance the inner cable moves in/out) you can adjust it somewhat, but I'm not sure if you can with that throttle cable (maybe too short? / not enough "throw"). You might want to take a close look at it, maybe even loosen/move the bracket or screw it in/out...just see what you can do. In a perfect situation, the cable will let the carburetor close completely when you let your foot of the gas (this is critical) AND open the carburetor up completely when you floor it. It "sounds" like your cable doesn't have enough throw which is preventing your carburetor from opening up completely. I'm sure that's holding you back, not the size of the carburetor.
3. Yes, you can get a decent increase in compression (if necessary) by using "closed chamber" heads, either 915's (hi-perf '67) or the other pre-68 heads if you put in the larger exhaust valves (68+). Some aftermarket heads are "closed chamber" too. You can also run the thin, factory-style head gaskets. HOWEVER, changing heads takes about a week of evening & maybe $1500, so if it were me, I wouldn't do it on my wife's car if it's her daily driver.
4. My suggestions would be A. Adjust/replace the throttle cable and B. See if you can find a deal on a 600 or 750 Holley single pumper or maybe a 650 cfm Edelbrock/Carter carburetor. Then see how it performs and go from there (throttle cable first for sure).
 
PurpleBeeper said:
1. In general, a 750 DOUBLE PUMPER is A LOT of carburetor for a relatively stock motor...not the end of the world, but don't expect too good of gas mileage.
2. It does look like you have a Lokar or some other aftermarket throttle cable. If there is enough "throw" in the cable (i.e. the distance the inner cable moves in/out) you can adjust it somewhat, but I'm not sure if you can with that throttle cable (maybe too short? / not enough "throw"). You might want to take a close look at it, maybe even loosen/move the bracket or screw it in/out...just see what you can do. In a perfect situation, the cable will let the carburetor close completely when you let your foot of the gas (this is critical) AND open the carburetor up completely when you floor it. It "sounds" like your cable doesn't have enough throw which is preventing your carburetor from opening up completely. I'm sure that's holding you back, not the size of the carburetor.
3. Yes, you can get a decent increase in compression (if necessary) by using "closed chamber" heads, either 915's (hi-perf '67) or the other pre-68 heads if you put in the larger exhaust valves (68+). Some aftermarket heads are "closed chamber" too. You can also run the thin, factory-style head gaskets. HOWEVER, changing heads takes about a week of evening & maybe $1500, so if it were me, I wouldn't do it on my wife's car if it's her daily driver.
4. My suggestions would be A. Adjust/replace the throttle cable and B. See if you can find a deal on a 600 or 750 Holley single pumper or maybe a 650 cfm Edelbrock/Carter carburetor. Then see how it performs and go from there (throttle cable first for sure).
Click to expand...

Thanks! I made some improvement by re-aligning the cable bracket and adjusting the cable... but I don’t see it getting any better, and I still can’t reach full WOT, because the pedal meets metal. There’s still cable and room for it at the carb, but the pedal can’t go any further closed, or any further open.

As far as heads go, if I was swapping them I’d source a whole set, prep them and have all my gaskets on hand, and then I can change out the heads in an evening. I’m a pretty good wrench, I just know more about modern cars than I do about 440’s and carbs. I pulled the 318 and 904 out of my 72 charger, completely stripped it down to nuts, sent some hard parts out for work, sourced and prepped replacement heads, rebuilt the trans, put the motor all back together, and got it all back in the car and driving down the road (with the addition of headers and a floor shifter) in about 3 weeks.... entirely alone with no spare hands.
 
That is a Lokar cable. The inner cable is retained in the front part at the carb linkage by 2 set screws. Loosen the screws and pull the cable loose. Pull the inner cable forward until your gas pedal cable end is tight against the inner firewall. Measure and cut the cable so that it fits back in the part that attaches to the carb linkage. You can make fine adjustments by loosening the 2 nuts on the cable mounting bracket to make the cable tighter or looser. You can read the directions on Lokar or Summit's site.
 
Last edited:
coloradodave said:
That is a Lokar cable. The inner cable is retained in the front part at the carb linkage by 2 set screws. Loosen the screws and pull the cable loose. Pull the inner cable forward until your gas pedal is tight against the inner firewall. Measure and cut the cable so that it fits back in the part that attaches to the carb linkage. You can make fine adjustments by loosening the 2 nuts on the cable mounting bracket to make the cable tighter or looser. You can read the directions on Lokar or Summit's site.
Click to expand...

Thanks! I actually did all of that minus trimming the cable. That combined with realigning the cable bracket took me from ~50% max throttle to about ~80-85%. I’m gonna give it a bit more love, and see what happens... plus the lokar cable bracket doesn’t like to stay aligned, thanks to the throttle return springs being attached to it and causing it to rotate forward with hard throttle. I’ll have to make a means to stabilize that bracket or hook the spring elsewhere...

Of course, now that I can actually actuate the secondaries with the pedal... the secondary accelerator pump does nothing. Hoping its just clogged frm disuse, and cleaning will suffice.
 
You are definitely headed in the right direction and Coloradodave seems to know a thing or two about Lokar cables, so follow his lead. Almost for sure the accelerator pump diaphragm in back, it's spring, the fuel feed hole in the rear fuel bowl (for the accel. pump) or the squirters are gummed up. All of those can be repaired without removing the carburetor & the only thing to really watch out for is if you pull the rear squirter out, don't drop the little bee-bee or pin underneath it down the carburetor throat & don't over-tighten the screw that holds it in. You are on your way, so bring it on home & burn some rubber!
 
PurpleBeeper said:
You are definitely headed in the right direction and Coloradodave seems to know a thing or two about Lokar cables, so follow his lead. Almost for sure the accelerator pump diaphragm in back, it's spring, the fuel feed hole in the rear fuel bowl (for the accel. pump) or the squirters are gummed up. All of those can be repaired without removing the carburetor & the only thing to really watch out for is if you pull the rear squirter out, don't drop the little bee-bee or pin underneath it down the carburetor throat & don't over-tighten the screw that holds it in. You are on your way, so bring it on home & burn some rubber!
Click to expand...
Thanks! I’ve decided also to measure and see if I can switch holes in the carb linkage... there’s one hole for the ball-pin that is closer to the throttle shaft, which should mean it requires less travel of the pedal to effect full rotation of the linkage... we’ll see if it is workable. I’ll almost certainly have to trim down the cable to use that one, so I wanna be sure I can before I make it permanent.

The hole in the red circle is the one I’m aiming for.

93147EEC-8DEC-4883-B639-5C4AD7ED80C8.jpeg
 
Also, can anyone verify for me that the hole in green is an adjustment option for the progressive secondary link? Like, can I move the secondary hook down to that hole and change when the secondary comes on?

10E03F80-DFFB-4E0B-BBA0-833B55CCB0C3.jpeg
 
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