Ok I'll try that in the morning after I get gas and report back. The fuel pressure dropped from 6 to 3 and fuel filter went from full to under half. So I'm guessing she's about out. Thanks again

Ok, so with engine warmed up I did make sure it was going to diesel, and it did. I backed off screw to the same place as yesterday and reshimmed it. When I pulled the shim, it died immediately with no diesel. The 3 videos are included. I did not have to put pressure on the plates nor would I have time to close off the vent tubes.

2 hours ago, Wrongway said:

Ok, so with engine warmed up I did make sure it was going to diesel, and it did. I backed off screw to the same place as yesterday and reshimmed it. When I pulled the shim, it died immediately with no diesel. The 3 videos are included. I did not have to put pressure on the plates nor would I have time to close off the vent tubes.

Wrongway, let’s see if the issue is with the front primaries. This time give the back, secondaries about a 1/16 or so opening. Doing the same test as you just performed. In his way the primaries will get closed of, but air will still be able to enter the intake system through the secondaries. If this test shows the engine not to diesel then I would feel confident the issue is in the front primaries.

Edited April 30Apr 30 by Last Indian

OK so I'm not sure about the secondaries, the only way I know to do that is at the butterfly on top. I pointed to it in the picture. If that is not how you wanted it done, I'll be happy to do it how you want it if you can tell me how. So, I did open the secondary butterfly, door not sure what to call it now and did the same test. Again, it shut off immediately. Two videos included.

11 minutes ago, Wrongway said:

OK so I'm not sure about the secondaries, the only way I know to do that is at the butterfly on top. I pointed to it in the picture. If that is not how you wanted it done, I'll be happy to do it how you want it if you can tell me how. So, I did open the secondary butterfly, door not sure what to call it now and did the same test. Again, it shut off immediately. Two videos included.

See picture below. The top butterfly will open when the secondaries throttle plates below open. Some where on either side of the lower shaft is either a setscrew & a stop that the set screw bumps up against or at least a lever that stops it. Using your paper shim idea, use that of a thickness large enough to hold the secondary plates open a 1/16 or so. You can verify that’s the right shaft by opening the top butterfly & looking down in. With the engine turned of push the throttle linkage full forward the should fully open all 4 barrels. Notice which shaft rotates for the back secondaries.

Edited April 30Apr 30 by Last Indian

Ok so I know I shouldn't use a screwdriver, but I did. I was able to more confidently set a 1\8th inch gap and make sure it rested where it would not move. Same results, when shim was removed the engine died with no dieseling. Videos included

47 minutes ago, Wrongway said:

Ok so I know I shouldn't use a screwdriver, but I did. I was able to more confidently set a 1\8th inch gap and make sure it rested where it would not move. Same results, when shim was removed the engine died with no dieseling. Videos included

Ok, I’m not sure we are on the same page. So see the attached pic. I think that may explain it better. The top butterfly only opens when the bottom throttle plates open.

Where the two red make areas come together stops the bottom plates from closing all the way. There is undoubtedly an adjustment, but if you just place a shim between the two to hold the plates open about 1/18 to an 1/8 that should work.

Edited April 30Apr 30 by Last Indian

So we did get a small, amount of dieseling. Here are the new videos. Thanks again for all your help.

1 hour ago, Wrongway said:

So we did get a small, amount of dieseling. Here are the new videos. Thanks again for all your help.

A couple last question. What is the compression ratio? What grade gas & what is the initial timing at? That said or ask, I believe good news, bad news. Good news it is fuel & I’m confident it’s the carb! Bad news I don’t know where you stand for remedying the carb? Rebuild by another? The carb should be rebuildable, but not being there I can’t tell you where the failure is.

Did you completely rebuild the current one? If not what was done? Carbs are simple & complicated at the same time.

I went back & was skimming through the gas tank issue & the pump issue, etc. if I had to bet money I would guess some where there has still been debris in the system somewhere. Or even possible missed debris in the carb.

A carb that has had that kind of contamination not only needs cleaned, but completely dismantled. Each & every passage, jet, power jet & needles needs cleaned out with wire or very small brushes & compressed air. Each face surface needs checked for flatness & a smooth good seal surface. The bores of the Venturi’s smooth & clean. I would always 00 steel wool. I would always dismantle the throttle plates & shafts so I could clean the outer part of the Venturis as well as throttle plates, but you must know how to do this as the screws that attach the plates to the throttle shaft are staked. And the list goes on.

1 hour ago, Last Indian said:

What is the compression ratio? What grade gas & what is the initial timing at?

Compression I believe we did 10 to 1, the gas we bought today was 87 and time timing, I honestly have no clue. We had all kind of timing issue and turned out to be the module in the HEI ignition. Once replaced both of my digital timing lights stopped reading the engine. Pertronix claims that their distributor puts out too much power for a "normal" timing light to read and gave me a part number to a snap-on timing light. They claim it is the only light that will work. The cost was justa over $700 on the tool truck. With help from the guys on here we set it by vac, rpm, how quick it started, by "ear" and non-dieseling and it seemed to be pretty close. I know that's not a technical answer, but I didn't have the $700 for the timing light they recommended.

As far as carb goes, It was opened up and I changed all the gaskets once in case it was leaking or sucking from a torn gasket, it was opened to replace the needles and seats and I found a hole in the float, so I repaired that, Still having issues I bought a new set of floats and replaced the repaired ones. After all the contamination I disassembled everything inside, needles, seats, metering rods, springs, squirters, venturi's everything except the primary and secondary butterflies underneath the very bottom of carb because I had no way to remove them and I did not remove external linkage. I used 1 1\2 can of carb cleaner, toothbrushes, heavy duty 6" gun cleaning Q-tips, cotton patches and microfiber patches and 2 pieces of wire strand that I pulled out of a piece of 18ga wire to clean everything. I did blow air from my compressor (low pressure, like under 5psi) through everything after shooting aerosol carb cleaner through everything. Then reassembled using another new gasket set. Every single part that was replaced was Edelbrock brand so I knew it would be to spec and I wouldn't be second guessing.

Also, I did disconnect the fuel line at the pump and blew out the fuel line from front to back, once when I removed the carb and once before reinstalling it.

Edited May 1May 1 by Wrongway

14 hours ago, Wrongway said:

Compression I believe we did 10 to 1, the gas we bought today was 87 and time timing, I honestly have no clue. We had all kind of timing issue and turned out to be the module in the HEI ignition. Once replaced both of my digital timing lights stopped reading the engine. Pertronix claims that their distributor puts out too much power for a "normal" timing light to read and gave me a part number to a snap-on timing light. They claim it is the only light that will work. The cost was justa over $700 on the tool truck. With help from the guys on here we set it by vac, rpm, how quick it started, by "ear" and non-dieseling and it seemed to be pretty close. I know that's not a technical answer, but I didn't have the $700 for the timing light they recommended.

As far as carb goes, It was opened up and I changed all the gaskets once in case it was leaking or sucking from a torn gasket, it was opened to replace the needles and seats and I found a hole in the float, so I repaired that, Still having issues I bought a new set of floats and replaced the repaired ones. After all the contamination I disassembled everything inside, needles, seats, metering rods, springs, squirters, venturi's everything except the primary and secondary butterflies underneath the very bottom of carb because I had no way to remove them and I did not remove external linkage. I used 1 1\2 can of carb cleaner, toothbrushes, heavy duty 6" gun cleaning Q-tips, cotton patches and microfiber patches and 2 pieces of wire strand that I pulled out of a piece of 18ga wire to clean everything. I did blow air from my compressor (low pressure, like under 5psi) through everything after shooting aerosol carb cleaner through everything. Then reassembled using another new gasket set. Every single part that was replaced was Edelbrock brand so I knew it would be to spec and I wouldn't be second guessing.

Also, I did disconnect the fuel line at the pump and blew out the fuel line from front to back, once when I removed the carb and once before reinstalling it.

Ok, I hadn’t read the part about timing! That coupled with 87 octane could be a big problem! So, again, first things first. Before any carb work let’s verify fuel quality & timing! Summit Racing shows a Innova 3568 timing light for $90 bucks that should work with your Pertronix. So if that’s in your budget, call Summit & talk to them. Tell them what you have & they should be able to tell you if it will work. If you can do that & if it works with the Pertronix, you then need to increase your octane to at least 89 & 91 would be better yet. Remember fuel & timing go hand in hand. Unstable fuel, I.E. 87 octane, bad timing causes detonation! Detonation causes dieseling when shutdown due to unstable fuel. Neither of those require a spark as it is spontaneous combustion. In turn continues the cycle of induction fed fuel when a carburetor is the fuel distribution point.

Ok, I'll reach out to Summit first. If they say it will work, we'll get that ordered. These are the two lights I have in house. The first is a Bosch the second is Actron.

Should I open the carb back up and clean it out again while we're waiting for the new light to come in? Or justa wait and not touch anything?

Edited May 1May 1 by Wrongway

15 minutes ago, Wrongway said:

So I guess the plan today is to remove to carb again and see what it looks like. I've been thinking about what you said. I don't remember it we cleaned out the pump after replacing the tank and blowing out the lines and the last time a cleaned out the carb. I would like to think I did but I'm not positive. In my head it seems logical that if there is trash stuck inside allowing gas to continue to run into the engine that it would most likely be in the needle and seat or floats. It seems like if it was in a squirter or passageway it would be blocking fuel from getting in. If I'm wrong, please correct me. Regardless I figured I'd give it one more go around before buying another one.

No, I would not pull the carb yet. Try stepping through the timing & fuel quality first. There are some octane boosters at the auto stores that will increase octane. & if the timing light I mentioned isn’t in the budget there are still other ways to get there. Fuel is definitely the issue, but that can present itself in the form of poor quality (octane) & timing.

I wrote that before seeing your reply and my computer froze up as I tried to edit it. Sorry having computer issues right now for some reason. The edit finally went through ahead of your last post. I'm going to call summit and wont do anything until I report back.

14 minutes ago, Wrongway said:

I wrote that before seeing your reply and my computer froze up as I tried to edit it. Sorry having computer issues right now for some reason. The edit finally went through ahead of your last post. I'm going to call summit and wont do anything until I report back.

I would see no harm in getting a good octane booster & treating your current tank to the proper amount that would bring it up to around 90-91 octane. Put everything back where you had it, or at least close. Then let the engine idle long enough to cycle enough fuel through to have the high octane in the carb. Then get the engine hot & see what results. This way if you get the timing light you’ll already know that if it’s still dieseling & then you check & change timing & it stops, it was predominantly timing.

I will do that. I also justa got off the phone with summit. I gave them the dist. part number and the module part # I replaced. Grover and his tech both said the only way the Innova light would not work is if the module I put in was a multi spark. Both said the part number I put in was NOT a multi spark and the Innova should work and they didn't understand why the two I have quit working with this dist. So I will pick up some octane booster and get the new light ordered.

Now, do you have an octane booster that you would suggest? If not I was looking a Lucas 3X or 104 octane boost

Edited May 1May 1 by Wrongway

27 minutes ago, Wrongway said:

I will do that. I also justa got off the phone with summit. I gave them the dist. part number and the module part # I replaced. Grover and his tech both said the only way the Innova light would not work is if the module I put in was a multi spark. Both said the part number I put in was NOT a multi spark and the Innova should work and they didn't understand why the two I have quit working with this dist. So I will pick up some octane booster and get the new light ordered.

Now, do you have an octane booster that you would suggest? If not I was looking a Lucas 3X or 104 octane boost

Yes the Lucas would be good.

Ok then thats what i'll get. The light is ordered.

On 4/30/2026 at 1:21 AM, Last Indian said:

The color of your spark plugs doesn’t concern me. I don’t know what fuel they run in NZ or Australia, but in the US we only have unleaded today. So all you’re going to have on the plug is black carbon or a medium gray color & the medium gray is rare in most carbureted cars today. You only get a tan or brown color with leaded fuel.

Wrongway - here is a pic of one of my plugs I pulled today specifically to show you. After a total rebuild my engine has done perhaps 8000 miles. This is how your plugs should look.

And for general information for anyone who cares, Australia switched exclusively to unleaded in 1986. I run a minimum of 95 in the GP (98 when I'm flush with cash) because it's 10.25 compression. It even says that in the 1965 owner's manual.

I am not expert enough to diagnose what's going on with your engine, but your plugs are choked with carbon. This tells me you have an excessive rich mixture at the very least. If you can get the damn thing to run, chuck some premium gas along with fuel cleaner in it and give it a good long high speed blast.

If the mixture is rich, after it's warmed up you should be able to either see raw fuel coming out the exhaust or see black smoke or smell fuel. If the fuel pressure, carb adjustments & timing are all good you shouldn't be having a problem.

Certainly a big difference from fitzy wrongway !

Edited May 2May 2 by 64 kiwi boni

Wrongway, I know you Justa want to get your GP fixed so you can enjoy it! So I’ll continue to get you there as long as you want the help. 

That said; flying down the highway at high speed resolves nothing, zero! In fact, if the issue is fuel quality & timing exacerbated by over-fueling you very possibly could have detonation going on that you don’t here! So taking that advice might prove ill advised. Yes, the black carbon you see on your spark plugs is fuel! I think we established that. What has also been mentioned by Frosty as well as myself is carbon deposits are not causing your issue. As some wish you to believe. As the engine is too new & furthermore carbon deposits are predominantly, about 92%, come from burnt oil! Not fuel! I don’t think your new engine has that kind of blow by! Stay the course. Step through the fuel quality & timing as previously mentioned. Once that is proved or disproved, move back to the carb if need be.

Thanks for all your suggestions. I do agree that the plugs have excessive carbon build up. I still think it was caused by the Holly fuel pump that was eating its self up and bubbling fuel over the top of the carb and flooding it out. But honestly at this point I'm doubting everything I ever thought I knew about engines. As far as hauling ass down the road to "blow it out", normally I would be all about it, but remember were talking about an untested car, new suspension, rebuilt motor, rebuilt trans, 4 wheel disk conversation and nothing as been over 20-30 MPH. So burning up the road is a little scary at this point.

Edited May 2May 2 by Wrongway

That might be half the problem. If the engine has been playing up and hasn't been for a decent run for months, it's probably no wonder the plugs are fouled what with all the over fuelling issues you've had.

Despite what others think, a good run does wonders for any engine once all the parameters are correct. Engines, like cars are designed to be in use and don't like sitting around.

Personally, I would have given up on this weeks ago and had the car looked at by a professional - you know the ones who have decades of experience and work in a well equipped workshop, BUT lotsa opinions here and guesswork gets expensive & frustrating. It'd be nice to get everything sorted and then all you have to do is maintain it. I was man enough to give up and let a pro do the final touches on my car. It's not an admission to weakness to not be able to fix everything. Damn car runs like a train.

I'm getting a new patio built because it's something I don't want to do. It's going to be expensive and I COULD have done it for a quarter of the price myself, but I want it to stay up and not kill someone when it collapses.

We are all passionate about seeing your car on the road.

Edited May 3May 3 by Fitzy

2 hours ago, Fitzy said:

That might be half the problem. If the engine has been playing up and hasn't been for a decent run for months, it's probably no wonder the plugs are fouled what with all the over fuelling issues you've had.

Despite what others think, a good run does wonders for any engine once all the parameters are correct. Engines, like cars are designed to be in use and don't like sitting around.

Personally, I would have given up on this weeks ago and had the car looked at by a professional - you know the ones who have decades of experience and work in a well equipped workshop, BUT lotsa opinions here and guesswork gets expensive & frustrating. It'd be nice to get everything sorted and then all you have to do is maintain it. I was man enough to give up and let a pro do the final touches on my car. It's not an admission to weakness to not be able to fix everything. Damn car runs like a train.

I'm getting a new patio built because it's something I don't want to do. It's going to be expensive and I COULD have done it for a quarter of the price myself, but I want it to stay up and not kill someone when it collapses.

We are all passiomate about seeing your car on the road.

wtf !!! hahaha! send a 1963 gp to a shop !!! no way aye wrongway !!!! pffft !!!

We learn by doing !!! when you stop learning .... your dead !

Edited May 3May 3 by 64 kiwi boni