I finally have my 512 low deck in my Super Bee and I have started the tuning process. I've driven it around a little, put about 10 miles on it today without much issue. I'm curious what everyone sets their timing at on their combo? I know big block timing is normally most comfortable around 38 degrees, all in by 2500. I was also talking to someone that said the strokers like a little less timing. So far it hasn't given me the ride I expected out of a 512, so I'm ready to do some experimenting with the timing before I move on to the carb . It was starting hard and dieseling, as well as running hot and not idling. I've got it starting nice, idling well, but it still runs hot. 210 or so.
I'm slowly getting it dialed in, (very slowly) but would like to know what has worked best for others with similar combos. Thanks.
My combo real quick:
'78 400 block, .040 over.
440 Source 4.25" stroke with ultra light crank.
Dished pistons.
Trick Flow 240 heads.
Cometic head gaskets, 10.6:1 compression.
Hughes roller rockers.
Scott Brown solid cam .563/.555 lift, 248/258 duration @.050. Installed advanced 4 degrees.
MP M1 single plane intake.
Proform 1050 with 4150 base.
MSD Pro-Billet distributor with a Digital 6AL box.
Initial timing set at 17 degrees with the total set at 38.

I've ran 451" it liked 34* total, running a 483 at 35* total had a 512and it liked 35*. So my experience they all seem to like 34-35 total timing. And that is running all on methanol.

We like 38*...We have run as much as 44*...It liked that too, but would ping on a hard launch when temp was over 170*

24 initial, 35 total,,about 6 more ported vacuum advance.

36 off a crank trigger

All the iron headed motors I've tuned on the dyno and at the track like right at 34 to 36 max on both race gas and pump swill
BTW,, all of them would slow down with 33 and 37 total, which works well when your trying to slow the car down for a index. Retarding it is way safer than advancing them also
Aluminum headed motor may like more timing also, no two motors are identical, just like timing lights and timing marks, correct
I like to retard the timing a little at a time until the car starts to slow down and then go the other way one degree at a time until it stops going faster and then split the difference to be safe

Mine on the dyno didn’t gain anything going over 34 at WOT. I’m at 15 cranking 23.5@ idle.

10.25:1, stealth heads, 240°s @.050

Mine likes 34 total. Didn't pick up any at 36 and slowed down at 32.

With the TF heads and that cam I'd start with 20 degrees initial and 34 total. For street driving you'll need some vacuum advance. The Trick Flow heads will get super hot at part throttle unless you give them some advance. If I was programming a curve I'd put 40 degrees at cruise and light throttle.

Then there's the 440/906 combo my dad has. 11.3:1, 565 cam, dist. locked at 40 and that's what it likes. edit: and that's on pump gas with a little bit of octane booster.

It looks like that for the most part 34 degrees is pretty common.
Andy, vacuum advance is a problem... My distributor is lacking a vacuum canister.

This topic comes up once in a while and as such, I took a poll at the drag strip two years ago. There was no mopar racers running a wedge that had it lower than 36. All racers I talked to were between 36 and 38. This was about 20 mopar racers. And most had all timing in between 1500 and 2K. I have asked this many times since then and its always the same result*.


Years and years ago a well experienced racer gave me some advice, "If everybody is doing it, its probably a pretty good idea".


As stated above, the time marks and the light may change things and every engine can be different. Good luck.




*One racer had his at 34 degrees, and he did this to slow it down. He still messes with timing to run his index.

I have pretty close to your setup. 400/512 TF heads Solid FT 244*@50 .555 intake 252*@50 .563 exhaust with the LSA @ 112 with 10.3 comp M1 intake Thumper Carb 850. Next week were gonna fire it up and break the cam in on the run in stand. Had Don at FBO set me up vacuum advance dist. Not having the sheet in front of me. If I remember correctly. This is what he sent me. Initial 22* 34*total all in @ 3200 rpm 12* vacuum advance @ 10". Won't know how the vacuum advance curve works while doing cam break in. But if we get it on the dyno. Should be able to check it then.

I'd be interested in seeing your results. I'm thinking I made a mistake putting a distributor without vacuum advance on it.

Yeah me too. Will see. This will be 99% street car. With a occasional strip pass. So street manners is way more important to me. Shoot FBO a call. He may tell you vacuum would help or just get yours recurved.

400/511 11.3:1, 270@50SFT .650 , MW Edelbrock looks to have same chamber design as the 440-1 by Indy. Reading my plugs mine likes 35*-37* total. Have a short curve in it with 31* initial 36* total and all in by 2500. Havent ran it yet to see what it wants exactly. This is 99% street driven.

Another vote for FBO. Swapped their vac-advance distributor with their clever plate into the 512 I had, 20 initial max 36, cleaned up the plugs a ton from the previous mech adv setup.
Drove nicer too.

My advice.. start advancing the timing you have a temp issue first..

I have posted it before but, get into the 21st century, engine programs are out there that will calculate the proper advance curve for what ever engine combination you have with what ever fuel octane you have. Are they 100% accurate, no, but they are close, at least in my experience. I use performance trends engine analyzer. As with all programs you have to take the time to input good info, if you do, it hits not only HP and Torque, but things like idle vacuum, timing curve, cranking compression, fuel volume requirements, and much more. I never build an engine without running it through the program. I get a lot of people who bring me a pile of parts to build an engine with, the program helps figure out if its a combination that will work, and helps convince them if it won't. Plus the program is a lot cheaper than a burnt piston, and fun to play with on a rainy day.

Mine will also be mostly street, but I'm undoing some old advice I've adhered to over the years, i.e. that vacuum advance is for old ladies. I have an MSD pro-billet, so changing the advance curve and such is simple. However, 20 initial and 34 total isn't, so it looks like I'll be buying some bushings off the FBO site.

Hey I’ve been where you’re at and even after buying the aftermarket bushings I still had to make them smaller to run over 20° initial on my old 408. I don’t have a lathe so I pinched one on a bolt and chucked it in a drill then went to town with a dial caliper and some 80 grit sandpaper. It took a while!

Luckily I have access to a lathe or two at work. Chucking up something that small may be a problem, but I can come up with something.

By all means build different bushings and do some testing. Eventually you'll come to the conclusion that the MSD pro billet distributor is a bad choice for a street car. If you want to accelerate your learning curve get an O2 sensor and hook up a EGT. Once you hook those two things up you'll start to see why you need vacuum advance in a street car.

The hot ticket these days is a fully computer controlled timing curve. My advice for anyone with a big stroker motor is to sell their carb and distributor and buy a Holley Sniper setup with the HyperSpark distributor. Then you get full computer control of the fuel curve and the timing curve.

Point 1, it's what I have to deal with at the moment, and I never doubted your previous advice. Better to get some bushings and make it close then to leave it with what I've got,right? O2 sensors are in the short term plans, probably after the Nats.
Point 2, I'm technologically about 15 years behind on my car. I just graduated from purple shaft cams and pinion snubbers. (I actually still have super stock springs for now) . Bear with me, sir, there are a lot of upgrades in the future as money and time allow.

My 493 Indy head engine likes 24 base and 34 total all in at 2000 RPM. Is it a perfect street car? Probably not but then mine is an old school 10 second stick car so it drives like street/strip car. I'm gonna hook up an A/F meter this season to dial in my new cam and intake deal though. I have a mechanical Firecore distributor with no vacuum advance with a Howard's 260/264 solid cam.

Gus

I know where you are coming from, I've been there myself. When I was younger I tried all sorts of stuff that people told me wouldn't work. Usually they were correct but at least I learned it for myself. Sometimes they were wrong and I figured out something new. Either way was a good experience for me.

If you have the time and patience to learn stuff the hard way then that is good since those lessons will stick with you forever. If you don't have a lot of time but you have some money then you can hire an expert to jump you to the next stage. There are pluses and minuses for each approach. Use whichever works for you. The important thing is to have a plan and to keep it fun.

Anyone modified an OEM-type vacuum advance unit to limit the travel/degrees of advance? They always seem to have too much...

So sad people waste so much money on junky msd distributers and then need to spend more money. And than they rot from the inside out. But here are bushings to help the really crappy design of the msd

https://www.ebay.com/i/222855820783...v-s-6dDraOyFDgjgVcrFk2U1W08aAtAUEALw_wcB

What about the adjustable ones that used a allen wrench through the vacuum port to adjust them

Yep, never been impressed with MSD products nor there tech line. Ice Ignition offers a electronic advance dist, but you need there ignition box as well. Ice Ignition has some nice stuff.

That feature adjusts the tension against the vacuum device, but doesn't limit the amount of advance. I don't know if a tight setting raises the required vacuum amount enough to keep the advance from using all the available arm movement.

I'm sure they could be modified by installing a stop but it might be easier to just change the can. I seem to recall that they came in different amounts. There is a number stamped on the can that tells the advance degrees. I used to have a box of vacuum canisters and I recall there being a few different advance amounts available.

Actually, I found an old Accel file that shows the amount of advance is what is controlled by the screw, not the amount of vacuum needed. But there is a direct correlation, that when you start limiting the advance, it slightly changes the amount of vacuum required. Either way, I'm working on a stock 440 with a fairly lumpy cam and a stock converter. A shorter vacuum swing with slightly higher base seems to be where this engine likes it.

I'm trying to put in the time to learn it the hard way. Getting the experience and understanding of tuning and timing is going to help in the future no matter what ignition I run.

Those are the ones I ordered.

So, let me pose this question. What is a good, tuneable ignition that can replace the MSD? Keep in mind, the reason I went with that is the ease of tuning. I don't have a welder to weld slots shut and then file them back open. An acquaintance that happens to need a low deck Pro-Billet distributor and I'm not attached to this one. I have an MSD box, so being compatible with that would be helpful.

I use the Crane fireball ....Works great, NO corrosion after 6 years..never failed..Tuneable ..

Hey Andy, can you post a screen shot of said timing table you are using with the TF heads.

i've seen pictures where someone used bailing wire or something similar, a quick loop around the arm that advances the plate in the dist and the travel was limited therefore the advance was adjusted...I will look for some pics when I have some time to get on the google...

I put the FBO plate in my Hemi, but with the vac advance hooked up, when you got off the gas after a banzai charge, it sounded like a machine gun as the 2-fours slammed shut, vac shot straight up and over-advanced. The guy at FBO told me that limiting the vac advance to add only 10-12* was the answer. I hooked my timing light up and, at idle, used the allen wrench to set it to 10* additional advance and noted the idle vac reading, this is using non-ported vac, as recommended by FBO. I shut the engine off, removed the cap and used my mity-vac to duplicate the idle vac on the advance can, used a sharpie to mark the arm where it goes out through the slot milled in the dist housing, drilled a 1/16 hole through the mark and put in a spring type roll pin, Problem solved! The pin physically limits the arm from moving further while allowing an additional 10* advance when driving normally. Backyard engineering, but it has worked fine for several years now.

THIS!

This is the one of the best ways I've read about to modify or limit the amount of canister vacuum advance. The small wrap of wire also sounds good. I have been contemplating adding vacuum advance too, and have been planning on welding and filling the vacuum advance canister arm to adjust the amount of vacuum advance to my engine's needs, but have not gone there yet. I don't know how to tailor the vacuum advance to my engine at cruise speed. Can anyone please describe the theory on that?

I am thinking of buying a quality vacuum advance equipt distributor, locking out the mechanical( or buying the MSD Programable box) Deciding which distributor to buy is a dilemma. I like the HEI style terminals, and would like to have a bigger cap that's high enough to clear my valve covers. No one makes one like that.

I really need to put a vacuum gauge on my motor to see how much vacuum I pull at cruise on the freeway. I know it idles in the single digits at 900 rpm, but don't know how much it pulls at steady state cruise out on the highway. I have always read it wants more that the 35* while cruising on the highway. I speculate probably 12* to 18* more, but how does one know what is optimal at steady state cruise and how does one test for that???.

I have tried all the bigger bushings from Four Seconds Flat, and the motor liked 22* initial with 35 total, but my timing was still bouncing around between 22* and 35* at idle. I tried using the stiffer springs which did help stabilize it , but the advance was coming in too late. I finally locked the Pro billet dizy out, and of course my timing is rock solid now.

On top of all this, my MSD Pro-Billet has a significant phasing problem. I have to use their pricey adjustable rotor at nearly maximum adjustment just to get the rotor lined up with the terminal. Taking care of the phasing problem dramatically reduced the wear on my cap and rotor for obvious reasons.

add vac adv amt till you are just under the pinging point in everyday driveing under varying load/RPM conditions on your hottest/driest (most likely to ping) day & the same on a steady interstate cruise (also on your hottest/driest day) & peoples' hearing varies & there is silent ping so give it a cushion. You want to be close to that line but never over it.

This is where the laptop tuning capability of the Sniper really shines. Get a buddy to sit in the passenger seat as you drive down the road and you can adjust the ignition timing while you drive. As you slowly add timing you can watch on the screen as the engine uses less fuel and drops in temperature. You just keep adding timing until it starts to tell you that it doesn't want anymore. Then you go smooth out the transition so the timing will drop back down as soon as you get into the throttle. You can do the same thing with a mechanical distributor but it takes a lot longer.

Our combos are pretty similar. Mine is 505 w 10-1 compression, TF 240 heads and Comp solid FT 248@.050, .538 lift, 110lsa, 950 proform carb and MSD pro billet.

I have timing set at 20 initial and 34 total. Runs great and no bogs or cooling issues. Havn't run it or dynoed, but seems to work pretty well.

If you take the time to learn how to properly set up the dist and get the vac advance lined out, you will never go back. Not talking about race cars that need locked out distributors. I have done a couple for my friends MP dist(old style) with the FBO plate and getting the canister right and they are much more responsive and actually picked up 1-2 mpg. On a street car, Vacumn advance is your friend.

This ^^^^^^^

I need to get this done on my 511. William Baldwin from Baldwin carbs says he once found 40hp on a dyno with the proper curve. He has a distributor machine and offers a service setting up dist. curves for your application. He does this for the circle track crowd particularly, but should work good on any street/strip deal.

My 63 is a 99% street car as its a 493 with Indy EZ heads. Its at 10.6 comp and has good .045 quench. It likes about 21 initial and 36 total. No vacuum advance as I got a great deal on a Mallory race dist with no vacuum advance. And I have full advance by 1800 rpm. The car runs awesome like that as it has great driveability. Ron

The internet story used to be that you couldn't have a decent running car by pulling the full timing in that quick. Of course, that doesn't seem to be the story now, at least with you and I. I run my total at 38, street and race. But I'm looking for the performance side of things.


You got your car cooking and you drive to the track. Running 10's, that is about as good as it gets, eh?

Mine likes all the initial I can give it. I suspect the 270@50 cam is the cause. I tried locked out, but starting issues arrived and I have a 10* retard start. The short 5 or 6* curve works for me. Need to get a vac dist on this thing curved by William Baldwin. I currently have 6" vac in drive, 9 in park and 16" cruising.

I'm currently using a mechanical-only distributor, but am interested in whether I can modify an older MP electronic distributor to work properly with vacuum advance. The problems I've had in the past was due to too much advance at cruise RPM and/or the rotor phasing causing misfires when the advance plate rotated.

I found something on FABO, IIRC, that a member there who I also see on occasion here ("Mattax"?) posted regarding modifying & tuning OEM-style electronic & single-point distributors w/ vacuum advance units. It has some of the same ideas that I had to try, as well as some testing results. If I find the link, I'll add it here.

I'm looking to pick up some MPG. This 511 is seriously thirsty. I spoke with Don at FBO about his vac distributors a few years back when they were still in development. He wasn't clear if they were available in magnetic pick up or if they would fit without clearancing the valve cover or aftermarket heads. I also looked into Ice Ignition distributors as they have an adjustable electronic advance with 10 or 12 different curves to pick from. You have to have their box thou. Don at FBO will custom curve your distributor if you buy from him.

Just looked at Don's site again and it looks like his vac dist are mag pick up. Cool. They have the wrong plug- in connecter thou. Maybe he would switch that out for me to the MSD type? I'm seriously thinking about getting one with a custom curve.

Good grief! Now that there is kinda funny! No offence intended but a 512 CID engine isn't going to known as a gas miser...

I knew someone would have a response like that. It is a little funny, but with the correct timing advance and more cruise timing using vacuum i'm sure it is possible to get a couple MPG better. I can't keep gas in this thing. A 15-20 mile cruise uses about 3 gallons of fuel, is that normal? Planning a 200 mile round trip and would like to see a little better fuel economy.

Something is wrong, it should get 8-12 mpg I would guess.

Yes she runs real good. Great throttle response at any rpm. Just step down on it and it goes. But I do have good quench and a custom grind cam from Dwayne Porter to keep my cyl pressure 92 pump gas friendly. The cam is a solid flat tappet with 264 & 270 @ .050 and .585 & .592 lift. Has a 110 LSA and I have it on a 106 ICL. My car has never had any ping at all and I have run it at 38 total also. Dwayne is very good as I told him I wanted bit lumpy of an idle as that's what I love and I wanted to make good power and run 92 pump and it has done just what I wanted it to. I forgot the intake closing as I have to look on the cam card but I know he has it right so I don't go over 200 psi cyl pressure. If I had a dist with vacuum advance I would try it and see how it does on my car but honestly I am more then pleased with how the car runs with just the mechanical advance dist. Course we can always do better.

As for my fuel mileage ?? All I can say is this 493 wanted a heck of a lot more fuel them my old 440 did and I have never checked the mileage as I knew it would eat a lot of gas. And I figure if I am worried about my fuel mileage on my hotrod then I am in the wrong hobby. Ron

Dwayne spec'd my cam as well and i'm very happy with it. Engine runs great and very responsive with decent vacuum, but like you say, always room for improvements. That's what keeps this hobby interesting. My Thumper carb is awesome as well, but I may be able to lean the jetting a bit in the cruise mode and add a vac distributor. These engines can make big power and get reasonable fuel mileage too as Dom has a customer with a large cubic inch big block making big power running the power tour getting 16 MPG. So gas miser or not better fuel mileage with these big engines is possible.

The key to good fuel mileage is the right foot position and low cruise RPM
Of course that include getting the AFR correct also along with the best ignition timing

Yeah, I agree cab. My right foot is part of the problem, but I return from a short cruise with a big smile every time. Torque is cool. My cruise AFR is 13.5 on average. Think I can clean that up with IFR and T-slot jets.

A lot will depend on fuel and carb type .
My 505 runs 13.2-13.5 @ cruise . It will hunt lean at 13.7 .
T slot changes only seem to be required on 4500 carbs .
As others have said before give the motor what it needs , dont chase the mythical number .
With my 29" street tyre , 4.1 gear and 6000 stall i cruise @ 3250 = 63mph thereabouts . Mostly our highway limits are 61mph (100kph) occassionally 65(110kph)
I get 8-9ish mpg daily 10-12ish highway . At 3500 (110kph) it all goes to #ell .
You want economy buy a Hyundai 😂

Tex

Two things- first unless I missed something nobody mentioned welding up the slots in a stock distributor plate to limit the advance. Second- here is the timing chart for my sniper/hyperspark 512 timing. If you’re not used to kpa instead of inches of vacum look it up it’s an easy conversion. My motor is super happy with this table downloaded to the ecu. It is a holley table that I copied from the free ‘v4’ efi software download and pasted into the sniper program. We tweaked it a little on the dyno but just plugging it in made the torque curve look like a plateau instead of bumpy steps. You might think it doesn’t apply to you but there is a ton of good info here and values that you can target with a mechanical setup.

I think he was talking about the transfer slots in a 4500 flange carb. But I could be wrong.

Well your 512 timing thread did take a left turn into fuel milage and cruise circuit tuning but I was not talking about fuel. (Although I never heard of changing the transfer slot- why would you do that when you can just alter the mix going to it with the ifle feed restriction and air bleeds?)

I was talking about taking a stock distributor and welding/brazing the slots in it shorter so that you can run less mechanical advance as in 24 at idle and 34 at wot. Combined with spring & vac pot selection and limiting you can dial it in pretty decent. If your motor wants a lot of initial you’ll still need a retard box to start it or a starter button separate from the ignition switch (get it spinning then light it off) to avoid kickback or slow hot starts. The hyperspark does all that for you but there are cheap ways to DIY that just take some more work.

A lot of the older drag race Holley carbs, especially the first gen Dominator, where flat pig rich in the transfer circuit so leaning that circuit down insured keeping the spark plugs a lot cleaner when driving back to the pits

What's worked best with my 511 so far is 36* read from the plug. No track time yet. Cruise 13.5 AFR,s with a 1150 Dominator.

Adding a restrictor to the transition slot passage gives you another tuning parameter. You can have the IAB and IFR right, but the sweet spot for the transition from the idle circuit to the main circuit is rich. I don't know about 4500s, but the 4150s I have with open transition slot passages are close to .120". Bringing that down to about .080" helps lean out that point so the transition is cleaner.