Looking back through the thread. You may want to try a regular solid air cleaner lid. Back when those filter lids came out I tried one and it made surging issues that seemed uncorrectable. I think it caused turbulence disruptions. However, I did have an open BOSS’9 scoop. A solid lid is an easy thing to try.
The Pinging was only happening at higher speed/rpm on the highway, not sure exactly since I don’t have a tach in the dash, and the speedometer is off since I swapped the rear gears. However I’d say I was going at least 55 when I noticed it
I’ll check the timing at 500 intervals, and post them when I find them out. Last time I checked the vacuum advance can started pulling at around 8", but that could be completely misremembered so I’ll get a vacuum gauge on it and check. I was planning to plug the vacuum advance and test it on the highway to see if it would still ping.
I believe I have a 170 degree thermostat, the car runs anywhere between 1/3 and 1/2 the gauge, the other day after sitting for a long while it went slightly above half, but at highway speed it was consistently around 1/3. I do have an aluminum 3 core radiator with 2 electrical fans, but I was only running one yesterday since the other is on a manual switch in the car.
I do have the 2v open chamber heads. Brent advised that I mill them a bit to get the chamber size down to less than or right at 73cc.
I was in 3rd gear when it was happening, I noticed that I wasn’t shifting into OD, which could be due to that shift kit, since before when the TV cable was way off it was engaging much too soon. I’ll be checking on that soon and figuring out how to better adjust that TV cable, since right now it’s at the recommended values for WOT and No Throttle, but perhaps it should be tighter.
As for that “Lean Sneeze”, it only happens while the engine is cold, after twice or 3 times around the block it goes from that to just hesitation on the shift, and it appears to be anytime it shifts up, not just 1-2. However 2-3 doesn’t seem as bad since I am at higher speed. Something I’ve done a few times was reading the spark plugs, and I thought that the popping could have been from a lean condition, however the way the carb was set up out of the box was causing black sooty plugs all over. Eventually I leaned it out and only had 2 black sooty plugs, #4 and #7, so we thought there was perhaps a vacuum leak there drawing in oil vapor, or just more air. I recently had the plugs out again and the rear 4 plugs (3,4,7,8) were all good, however the black/grey line on the porcelain was higher up than the front 4 plugs. So I went down to a 68 main jet in the rear, and it’s had no real issues since then, it also doesn’t smell as gassy. I’ve tried richer jets, up to like 74 and 78, and they all had the same lean sneeze.
I’ve tried to look for any spark plug wire glow or aura like people have mentioned before, didn’t see anything, but I can check again.
I haven’t done the foot brake RPM test, I was waiting till after I got the rear end back together and drove it a bit, and made sure my brakes were still good, but I’ll do that as well. I’ll also test a solid air cleaner lid.
I’d happily help pick a cam if you really want one, but even though you have a cam with healthy number, it may not be causing your problems
If I could ask some questions, forgive me if already answered
1 - Did you degree it? and did you put the cam events to where the card says?
That cam is ground with zero advance, 113 ICL (and actually 113.5 if you use the cam events) depending on your static compression, I would be running it as early 105 ICL if 10:1 or less, and no later than 106 or 107. If you are lined up dot to dot, or degreed at those specs, advancing it alone will drive low end torque and vacuum up considerably. If you don’t know your actual compression maybe we can back into it
2 - Once you got that figured out, I would likely put the carb back to stock in every way.
My hunch is that you were causing a lean bog due to a delay of a power valve and maybe some band aids. May need to go into the carb to tweak but I would put it back stock, even power valves. Some guys will follow old Holley lore that you need 1/2 idle vacuum, however under load you are then too lean. With yours, advancing the cam will drive up vacuum, and at that point, likely a 6.5 PV will keep it from leaning out
3 - Have the distributor professionally recurved.
Set it up for 16 initial, 20 mechanical, for 36 total, all in by 2800. Vac advance on top of that should give you another 6-8 and be run ported. This setup will keep plenty of advance for a slower port of a 351C that is very slightly overcammed. Again, the cam is only big if installed late, with 113 LSA it isn’t that rowdy
4 - While the distributor is being done, check the balancer/timing mark with a piston stop
A piston stop is a physical stop that happens any arbitrary number before and after TDC. By using one, the middle of those two points is TRUE TDC, and if a pointer is off, you can fix it before you try to time it again
5 - Just want to make sure you have the correct thermostat as well, as well as the restrictor plate to force all the water through the block, not a tuning tool, but it sure helps if they run cool
That cam is a little big-ish but you can’t only go by duration, it’s only 57 degrees overlap, and if it’s clocked to match your compression, should work fine. It will build vacuum in a 2V head, but not installed at 113 ICL
Hope this helps
Alright, after a lot of other issues popped up in life, and still working on a few separate things, I finally got some time to check on this and get some stuff sorted out, so I’ll try to address any questions or advice given here and give the most info I can. I’ve not been able to drive it on the freeway since, so I’ve only gotten to do some driveway tuning and measurements while parked in the driveway, but I’ll be trying to get it on the road soon.
I rechecked all the numbers I mentioned before and I was pretty spot on with them. 14" of vacuum at 800 rpm in park, 14 degrees initial timing, 21 degrees mechanical advance, all in about 2800.
I found out that my vacuum advance can pulls about 16 degrees of timing, topping out when it sees 11" of vacuum.
Here’s the timing values with no vacuum advance on, at 500 rpm intervals.
1000rpm: 15 Degrees
1500rpm: 25 Degrees
2000rpm: 32 Degrees
2500rpm: 35 Degrees
3000rpm: 36 Degrees
It got to 36 degrees total by about 2800 really, and above 2500 the reading seemed to get sporadic, harder to really narrow it down but I got it as smooth as I could. I had no pinging at all while testing this. I was surprised at how much the timing advanced just by 1500.
I’ll check the stall on the converter soon, I’ve been working on some brake stuff and want to get them done before checking that.
I didn’t degree the cam, I had the engine assembled by a local shop. As far as the paperwork reads, it is installed at 113; “Cam at 113 Intake Centerline”. I don’t have the exact readings for everything to determine compression, but based on the ranges of stock 351, and knowing that the chambers are 73cc and I’ve got a 2cc dome, I’d guess a ballpark of about 10:1 to 10.1:1. That’s where I was aiming when I let Brent know about my build.
I left the 6.5 Power Valve in it, at this point the only thing’s I’ve changed from stock is the jets, which are leaner than stock, the float bowl level is set, and I adjusted the secondary throttle blade opening a bit.
I do have a good thermostat and I did put in that restrictor plate. I’ve had no issues with heat, even with .020 bored over, I made sure to get the stuff to not overheat here in SoCal.
After taking measurements and getting it warmed up, I did fiddle with the air fuel mixture screws and the timing a bit. I was able to get 15" of vacuum at just shy of 1000rpm, by leaning it a bit, and bumping the timing up to 16-17 initial degrees. I checked with everything connected, and with it all disconnected, and it was the same, so no leaks in the auxiliary systems.
If I pushed the timing up quite a bit I could get it to maybe 17", but at that point my timing was well over 20 or 22 degrees, rpm was high, and I doubt I’d be in that range. I left it where it is, so I’ve got 15" of vacuum now, initial timing bumped up a bit, and the vacuum can off. Once I get a chance to drive it I’ll see where it pings and if I’ve got any issues or if anything is better.