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1967 400/400
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I think you've talked me into the Edelbrock...
In that case, you may be interested in these Superbowl Elevator Passes.

Seriously though, I never try to talk anyone into anything, I merely try to enlighten them to more options. Not sure how these carbs got such a bad reputation. The most sought after muscle cars ever made came with these carbs on them.

Im also not sure where the idea that they're not suitable for high performance came from. It's like a bad old wives tale. The pages of Car Craft and Hot Rod mag, along with the drag strip, are loaded with $250,000 machines, sporting Eddy carbs.
 

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Is the factory fuel pump going tp be ok with the 800 eddy? The 600 handles it just fine.
The issue with "OEM" fuel pumps is that they're inconsistent. Could be 6, could be 12... The Edelbrock design is such that too much pressure can flood things up. If it's no issue with the 600, than it's a very reasonable assumption that it's within parameters and safe for the 800.

That being said, one carb might be more temperamental about it than the other... If you're serious about tuning, then add a Marshall fuel pressure gauge and find out what you're running!
 

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army - Just a thought (and this could be a good thing) perhaps your suspension is just dialed in that well? I have seen cars that just hook and go if everything is perfect.

Otherwise, I assume you're running premium. Having traveled the continental US coast-to-coast driving trucks, as well as knowing someone who lives in Washington state, I know that certain locations require different octane ratings for altitude (85 octane for example), which affects the oxygen content of the intake air. Perhaps some octane boost or racing fuel would give that extra oomph that is missing?

I wonder if this might apply to predominantly cooler / colder climates also regardless of altitude. Say, for instance, your engine might do everything expected on 93 octane at say, average temps of 70 degrees, but perhaps average temps of 50 would stifle it somewhat. Also, I found some interesting info on the 670 heads you mention. Maybe all this was already done to yours, but might be worth a read.
I do have Global West upper and lower control arms, front and back, UMI sway bars and coil springs, Global West frame supports, Bilstein shocks with Sphon relocators, and teflon/ delrin bearings replacing all the rubber bushings. If there's one thing my car does well, it's staying planted on the road.

My last 67 seemed much more aggressive, but it had one-wheel-peel... So that's probably why.
 

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from reading this my impression is that open headers are causing a lean condition.
check some of your plugs, they should show signs of being quite hot...(burnt white perhaps?)
I would finish your exhaust system and then check again. you can rejet your carb now to have the correct AFR now but it will change again when you close up the exhaust.
You may want/need a different carb in the future but finish the exhaust first.
You are in a change-test-tune loop and if you make too many changes without doing the test & tune it will be tough to dial this in.
I think someone suggested an AFR gauge for tuning...probably a great idea.
 

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So i got my 69 back from the shop on the 18th after having them do the rear main and putting the flowtech headers on. It cost way more than i budgeted due to unforeseen issues so currently i only have open headers with just 2.5" collectors. Before the headers, with factory exhaust and stock style mufflers, the car would spin about 1/4 the way through first from a dead stop at idle by just stomping on the pedal and pull pretty nicely all the way to second gear, then pull well on into 3rd. Now it will burn all the way through first, shift into second, pull like the dickens halfway through second and fall flat on its face up until 3rd, then pull again and flat on its face... I'd say it feels like it lost half the power on the top end... The only thing that changed is the exhaust. Currently since i have an hei, the hood tach doesnt work so my guess is it's dropping off around 4000 to 4500. I've farted around with the timing, the carb and even tried non ethanol fuel and all i can manage to do is make it miss and idle rough or run worse. I did put a new air cleaner on that hit the hood so i put a 1/2 plastic spacer in and took out the 1" aluminum spacer i had originally, but i swapped all that back to the old stuff and nothing changed so im sure the new air cleaner and spacer have nothing to do with this. Its almost like its loading up on the top end but it isn't blowing black smoke nor does it smell likes its loaded up, plus its only a 600 carb so there's that...

Timing is set at 6deg at idle with the advance disconnected. The vac adv is hooked to manifold vac normally, switching it between port and manifold changes nothing but the idle. my 1970's sears timing light does not have the advance knob so i don't know where its timed with the vac adv hooked up but iirc its in the same place it was before the headers... all adjusting the timing does is make it worse...

XS code 69 350, stock cam (i think), 1971 #94 heads, edelbrock rpm intake, 600 summit carb, pertronics flamethrower hei. stock TH400, 3:23 safety-trac rear.

I'm thinking maybe I need more carb now? My fiance suggests maybe since it has sooo much more bottom end, the top just feels pathetic now...

Thoughts?
 

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So i got my 69 back from the shop on the 18th after having them do the rear main and putting the flowtech headers on. It cost way more than i budgeted due to unforeseen issues so currently i only have open headers with just 2.5" collectors. Before the headers, with factory exhaust and stock style mufflers, the car would spin about 1/4 the way through first from a dead stop at idle by just stomping on the pedal and pull pretty nicely all the way to second gear, then pull well on into 3rd. Now it will burn all the way through first, shift into second, pull like the dickens halfway through second and fall flat on its face up until 3rd, then pull again and flat on its face... I'd say it feels like it lost half the power on the top end... The only thing that changed is the exhaust. Currently since i have an hei, the hood tach doesnt work so my guess is it's dropping off around 4000 to 4500. I've farted around with the timing, the carb and even tried non ethanol fuel and all i can manage to do is make it miss and idle rough or run worse. I did put a new air cleaner on that hit the hood so i put a 1/2 plastic spacer in and took out the 1" aluminum spacer i had originally, but i swapped all that back to the old stuff and nothing changed so im sure the new air cleaner and spacer have nothing to do with this. Its almost like its loading up on the top end but it isn't blowing black smoke nor does it smell likes its loaded up, plus its only a 600 carb so there's that...

Timing is set at 6deg at idle with the advance disconnected. The vac adv is hooked to manifold vac normally, switching it between port and manifold changes nothing but the idle. my 1970's sears timing light does not have the advance knob so i don't know where its timed with the vac adv hooked up but iirc its in the same place it was before the headers... all adjusting the timing does is make it worse...

XS code 69 350, stock cam (i think), 1971 #94 heads, edelbrock rpm intake, 600 summit carb, pertronics flamethrower hei. stock TH400, 3:23 safety-trac rear.

I'm thinking maybe I need more carb now? My fiance suggests maybe since it has sooo much more bottom end, the top just feels pathetic now...

Thoughts?
If I am understanding this correctly, you are running open headers with a 600 cfm carb? You have way too much exhaust flow and at 600 cfm the carb is actually throttling the flow especially at higher rpm. I'm sure the secondary jets are too small. Put something on the end of the headers. I still think you'll a bigger carb at least 700 cfm.
 

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Seeking information on a 1969 Judge my folks owned
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I do have Global West upper and lower control arms, front and back, UMI sway bars and coil springs, Global West frame supports, Bilstein shocks with Sphon relocators, and teflon/ delrin bearings replacing all the rubber bushings. If there's one thing my car does well, it's staying planted on the road.

My last 67 seemed much more aggressive, but it had one-wheel-peel... So that's probably why.
Gee, ya think? 🤣
 

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Discussion Starter · #28 ·
So since i finished the exhaust and got those super quiet hooker turndown mufflers on it, it seems to be back to the normal "pre headers" power (or lack thereof). in other words, i lost bottom end but it pulls on the top better, like it did before. So im in the process of rebuilding my 3310-10 holley. im going to be putting the glasspacks on in place of the hooker pipes, swapping on the 750 and see where it feels "seat of the pants" wise. I have a feeling ill be happy with the 750 and thrush glasspacks, i bought the 28" ones and tips to turn them down before the axle.

at some point i need to make a decision on where im going with this car engine wise...

choice # 1: use the 350 that's in it and put on the '69 #46 heads and 068 or 2801 cam. it currently has 71 #94's and stock 2bbl cam...

choice #2: drop in the 557 400 with the 6X-8 heads and whatever cam is in it (i was told its the "largest flat tappet for a pontiac you can buy" whatever that means)... i bought it for this car running on a stand for $1000

choice #3: use the 400 with the small valve #46's and 068/2801

choice #4: dont do anything and wait until the speedmaster heads i got for my bday/xmas "birthmas" show up this spring/summer and then decide which engine to put them on... which would require me to leave it alone for the remainder of winter (doubtful)

sadly i dont have a "good" engine. i have two mediocre engines that restrict how much power i can get out of them. in the meantime, I'm saving up for a butler short block and maybe a built 400th trans... if i can scare the money up for the butler fast enough, the speedmaster heads will go on that and i wont be playing with 350's and glass 400's anymore...lol...
 

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You'll want to double check if your #46 heads are earlier castings. Unless I read wrong, the earlier heads had press in studs, which would need to be changed before you can go with a bigger cam.
 

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Agreed with Jared. I did that in my teens and I literally had to replace rocker arm studs once a week for the better part of a year. It got old real fast but it was the only option I had at the time
 

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Discussion Starter · #31 ·
You'll want to double check if your #46 heads are earlier castings. Unless I read wrong, the earlier heads had press in studs, which would need to be changed before you can go with a bigger cam.
What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...
 
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Discussion Starter · #32 ·
NVM, they came with the 067...
Dur.CL1.50:11.65:1O.L.Dur.CL1.50:11.65:1Part #
273112.407".447"54289113.407".447"9779067

maybe stick with the 2800 in the 350?
 

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Discussion Starter · #33 ·
1967-69 2bbl V8U269112.5.375".413"47277113.5.410".454"9777254
1965-76 4bblP273112.407".447"54289113.407".447"9779067
1965-72 HO S288113.407".447"63302119.407".447"9779068

so the car currently has the 254 cam which has more lift on the exhaust than even the 068, so wouldn't it be safe to assume that the intake studs would handle the same lift?

which brings me to one of my other ideas, 1.65"s on the intake valves instead of a complete cam swap... leave the 254 in the car, put the $$$ towards something else...
 

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What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...
iN MY OPINION, DON'T EVEN BOTHER GIVING YOUR BUSINESS TO PLACES LIKE THAT. Sorry for the caps lock...

It always ends poorly. But yeah, my 66 Lemans with a 350 and mild cam, broke press in studs CONSTANTLY!
 

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All of it is subjective, but do "whatever you can". Whenever buying bicycles, guitars, or doing car repairs, it always pays to do the best you can.

Meaning, if you can only afford oil, but not a filter, than leave the filter and change the oil... but that';s obviously not what you'd do if you didn't have to.

Same here... Youre a Pontiac guy. Therefore, you need heads with screw in studs. Either buy them, or get yours done... and if you're doing all of that work, then put in the cam that you want as well. It's not hard to make a lot more power than you need with a 350. Do a little gasket matching, square away your fuel and ignition... and a 350 is a ton O fun
 

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What cam did the '69 428 come with? As long as I don't go bigger than that I should be ok right? I've been contemplating have screw in stud installed, but the machine shop near me wont return me emails about when to drop them off and a ballpark estimate... I guess they don't need the business that bad...
It could be OK until it isn't. I'd hate for you to find out the hard way on this. You should be able to find a machine shop to tap the heads for a set of screw in studs. I can't imagine the cost would be too high. Problem may be finding a shop with time available. I waited 6 months for a short block build and 9 for the heads, and these were ordered close to 2 years ago now. I was told that those shops backlogs went way up when the pandemic hit. Evidently, folks uncovered their projects.

One suggestion would be to drive it as is and get your project on the que at a local shop. Pull the heads when your turn comes up to minimize the time your car is off the road. Side note, A lot of these machine shops operate the old school way. Free advice would be to pick up the phone.
 

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Discussion Starter · #37 · (Edited)
What about drilling and pinning the studs? I just read an article about doing just that and found a kit for it...

BTW the 46's are not on the engine yet...

 

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Discussion Starter · #39 ·
Pinning would not have helped me. All of my studs "snapped" where the threads began.
geez, what cam were you running?

I spent all night (i came in at midnight) reading articles and watching vids of how to pin the studs. i think im going to go that route with these 46's. worse case, i break a stud and end up putting the 94's back on before the speedmasters show up. once i get the aluminum heads, ill probably just sell the 46's, 94's and the 6x-8s off the 400 and just keep the 400 short block as a spare incase i blow the 350...

in reality, at this point i'd be fairly happy with the 330hp the 350ho boasted in 69, which is what i thought this motor was when i first bought the car. my motor is the 265hp with the 2bbl, 254 cam and #47 heads with cast exhaust manifolds. currently im running a 600 summit carb, edelbrock performer rpm intake, ceramic coated flowtech headers and #94 heads. i may go ahead and just toss the 46's on, put 1.65's on the intake valves and just be done with it until i get the speedmasters and pick a cam then...my holley 750cfm 3310-10 may be going on today, if i ever get off work that is...
 
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Discussion Starter · #40 ·
i didn t get off until noon so the holley is still on my workbench maybe today when i get off duty at 8am ill get it on...
 
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