Bullnose Gator

I was planning on trying 15W-40, so glad to hear that. At 70 it was at about 3,200 rpms, with 33" tires. I think they are stock because the speedometer is accurate.

I'd have to check, but I think it actually is a 4.10. Are you saying driving a 4.10 at 70 is bad? Please don't tell me I just broke something else lol! The leak is pretty bad right now, especially right after driving it while the engine is hot. It's leaving appetizer plate sized stains wherever I park it for more than 30 minutes.

After all the help yall gave me, just wanted to share that this weekend I drove the truck back to my hometown, over 2 hrs away. 70mph for the bulk of it, and it drove great there and back. I even pushed it up to 90mph for .00048 seconds, before getting scared I'd blow something up lol, and that wasn't even fully to the floor. Never thought it could go that fast. But I changed the oil right before the trip, and the fresh, probably too light weight (5W-30), oil made my RMS leak worse. I also determined that there's a small exhaust leak around the passenger side exhaust manifold/pipe. Looks like I'll have an enging yanking party in my future, but I'll save all those questions for another post. Just wanted to thank yall for all of your patience and help!

Well, there definitely was a vacuum leak. While I was packing up tools for the night I took a closer look around the engine and saw that one of the vac plugs on the manifold tree had popped off. Doh! I also noticed that a couple of the original vag plugs that were on that tree were also brittle and a little leaky. I replaced them all with new, snugger fitting plugs. I also opened the vac adv "can" a few turns, as suggested. Then I went back through the process again, but the results were nearly the same, readings wise. Eventually, I settled it in at +10 deg BTDC, vac gauge read 24in, vac adv dist can turned left 8 full turns, idle at approximately 700 rpm. When I put the vac hose back on the dist the idle went up to 1000, and the timing went to +30. So I adjusted the idle screw a touch to 750 rpms. The timing dropped to 28 deg. I runs a lot better than before, but I honestly don't know what "perfect" or as close to it as this old engine can get would sound like. I took it for a drive and it definitely has noticeably more "pep" than before, and drove great. It has a little bit of "glug-a-lug" to it, but not much, and the carb certainly needs a little more adjusting, but isn't far off. I'm going to go ahead and replace the carb with a holley or edelbrock 600-650 just to be able to tune the idle mixture screws easily, as they are NOT easy to get at and adjust on the 4180. I'm also going to replace the egr spacer gasket while I'm at it, to make sure there's no vacuum leak there, and maybe get/make a plate to block off the egr port, since the egr valve is just sitting there doing nothing anyway. So how does 28 deg initial timing sound? Is that going to do any engine damage that high?

So I gave it a shot. To be clear, my scale is -10, 0, +10, +20, +30, and no marks after +30. After getting it up to temp, I turned off the engine, pulled the vac hose off the distributor, and plugged it. I turned the engine on and turned the distributor slowly clockwise until it was at +10. It sounded much better. I went to +12 and it sounded like I crossed the line, because it started to back towards sounding bad again. RPMs were right around 750-800. I turned it off, tightened the dist nut, stuck the the vac hose back on the dist nipple and cranked it back up. It didn't sound good. I checked timing and it was reading +33 deg. Idle still looked good. Also, the vac gauge was pushing 23-25in throughout the process. I can't mess with it anymore tonight, but I'm wondering if I have a vacuum leak or something. I can almost hear a faint "hiss" with the vac adv hose connected, and it seems like it might get more pronounced when I disconnect and plug it. If it's not in my head, it sounds like it may be coming from the right side of the carb/engine.

Thanks. After setting the mixture screws to 2 full turns counterclockwise, here's where I'm at, with the distributor vac adv set to 8 full turns counterclockwise: With the dist vac adv hose CONNECTED: 14-15 Deg. With the dist vad adv DISCONNECTED and plugged: -0 deg (same exact place TDC)

So "back the can off" means to disconnect the vac adv hose?

Very helpful, Vivek, thanks. In that video he says an old engine that calls for 4-6 deg btdc is probably optimal at 14-16 deg. Is my 12-13 as an old engine not close enough? Jim, what does "back the can off" mean?

After my last post, it wouldn't start. Thankfully, I didn't waste hours before I realized it could be out of gas, and sure enough, it was! Lol So after I went and got 2 gal of super premium (93), and made a couple of store runs, I started testing timing, bit by bit. It read the same as last time to start, aprox 22 degrees. First, per the factory instructions on the radiator support, once up to temp I pulled the dist vac adv and plugged it. This made it run rough, and the timing dropped to a wobbly 12-15 degrees, and vac dropped as well: From there, the only adjustments I made were to the dist vac advance, which I learned is fully open (counterclockwise, if I don't have that backwards) at 10 full turns. I made 2 full turns at a time, all the way up to 10, and then all the way back down again. The results below were the same on the way up as they were on the way back down. Dist Vac Adv positions/readings (all turns counterclockwise): 1) Closed (turned full clockwise) = 22 deg and vac 21-22 in. 2) 2 full turns = no noticeable change. 3) 4 full turns = timing dropped to a wobbly 14-16 deg, vac 19-20in. 4) 6 full turns = timing dropped to a wobbly 13-15 deg, vac 17-18in. 5) 8 full turns = timing dropped to a steady 12/13ish deg, vac went back up to approx 20-21in. 6) 10 full turns = timing MIGHT have dropped a smidge, still 12ish deg and steady, vac MIGHT have gone up slightly, but not sure since the vac was a little jumpy at every point by about 0.5-1in. Here's timing/vac at 10 full turns: Questions: 1) Is the engine supposed to run rough when I disconnect the vac adv? 2) Yhe timing instructions say "800 rpm max" but I doubt it's at 500 with the vac adv hose off, am I supposed to have someone give it throttle up to 800 to see the timing at that point? 3) I want to take it around the block and see how it does. Which of the above dist adv settings looks like the best to set it at for that test drive? Lastly, these pups are some of the best around, Jim. We fostered this guy back in March after he was found after being left in a house for over a month by tenants that got evicted, he nearly starved to death. We knew from the first day he was never leaving us. Here's him when they found him, and now, doing what he loves the most - keeping me company while he waits for a chance to sit in the truck lol Thanks again for all the help!

I used a straw, and eyeballed when it stopped getting pushed out as closely as I could while holding it with one hand and cranking the engine with the other. Unfortunately, I'm a one man show, and the pup below is no help, smh. Here's where it reads at that point:

They can't transfer those today in time. I wanted to put them in today while I set the timing, but I agree, ordering and putting them in when they get here is preferred over going out of my way just because I'm impatient.

Yes Sir, 5 mins away. They have those plugs in stock. 8, to be exact. https://www.napaonline.com/en/p/NGK6630 These wires are available at another Napa a little further away: https://www.napaonline.com/en/p/BEL700233

Alright, guys. I didn't have much time to get back under the hood the last few days, but I did spend some more time here researching and over at youtube university. I've got the day cleared to get back to it, so I'm going to start with finding/marking TDC and re-checking time. I'm going to take Jim's advice that I saw in another thread and go ahead and replace the spark plugs and wires while I'm at it. I did replace the dist cap/rotor a couple of years ago, but I might start fresh there too. If you have any recommendations for plugs, wires, dist cap/rotor that would be in stock at the big chain auto parts stores here, definitely let me know, thanks. I'll let yall know how the timing looks after finding TDC first...stay 'tuned'...

So I need to adjust the distributor, or is this part of the recurving rebuild process to bring it back down?

Static...BTDC....more terminology for me to look up. Lol