‘69 RR ignition timing mild cam

[Jeremy Nelson]

Folks:

I have a ‘69 RR that I just purchased... stock (aside from an unknown mild cam), original, rebuilt 383, 4-speed. Stock intake, stock 906 heads, stock exhaust manifolds, unknown mild cam, Holley 670 DP (I just installed the 670). It had a Holley 600 on it when I bought it and I’ve just changed it for the 670. Both carbs are brand new. I used the 670 because I just had one around. New Champion spark plugs (gapped at .035), new wires, new distributor. Initial timing set to 12-24 Degrees BTDC. Setup the carb and seeing between 14-18’’ vacuum. Running 93 octane. 741 center section (I’ll be going to a 489 center section, 3.55 suregrip soon).

So here’s my claim/questions. The car just doesn’t run like it should. Seems to miss a little and is really sluggish. In my opinion, this rig should scream but it feels sluggish and seems that something is holding it back. I’m thinking about going to a Holley 750, mech. Secondaries and electric choke, along with an intake and headers. Questions are:
1. Again, unknown cam but a mild config. Has a nice lumpy idle. Do you all have any ranges that is should look to set the initial timing? What about advanced timing?
2. What carb should I be using? This car boys under load a bit and feels very sluggish.
2. What intakes will replace the original and with a Holley using the stock air cleaner (383 RR engine air cleaner) still clear the stock steel hood? Looks to be pretty close to the hood in the stock form. What combos (carbs/intakes) are some of you running and clearing the stock RR hood with stock RR air cleaner?
3. What kind of vacuum readings do some of you top out at when setting the jets?
4. What gear ratio are some of you all running on some of your mild 383 cars? My car is a really clean original resto, but I’d like to get closer to the 400 hp mark and complement with a gear set in the rear to have a bit of fun on the street. Thank you all very much in advance!!

 

[Jeremy Nelson]

Folks:

I have a ‘69 RR that I just purchased... stock (aside from an unknown mild cam), original, rebuilt 383, 4-speed. Stock intake, stock 906 heads, stock exhaust manifolds, unknown mild cam, Holley 670 DP (I just installed the 670). It had a Holley 600 on it when I bought it and I’ve just changed it for the 670. Both carbs are brand new. I used the 670 because I just had one around. New Champion spark plugs (gapped at .035), new wires, new distributor. Initial timing set to 12-24 Degrees BTDC. Setup the carb and seeing between 14-18’’ vacuum. Running 93 octane. 741 center section (I’ll be going to a 489 center section, 3.55 suregrip soon).

So here’s my claim/questions. The car just doesn’t run like it should. Seems to miss a little and is really sluggish. In my opinion, this rig should scream but it feels sluggish and seems that something is holding it back. I’m thinking about going to a Holley 750, mech. Secondaries and electric choke, along with an intake and headers. Questions are:
1. Again, unknown cam but a mild config. Has a nice lumpy idle. Do you all have any ranges that is should look to set the initial timing? What about advanced timing?
2. What carb should I be using? This car boys under load a bit and feels very sluggish.
2. What intakes will replace the original and with a Holley using the stock air cleaner (383 RR engine air cleaner) still clear the stock steel hood? Looks to be pretty close to the hood in the stock form. What combos (carbs/intakes) are some of you running and clearing the stock RR hood with stock RR air cleaner?
3. What kind of vacuum readings do some of you top out at when setting the jets?
4. What gear ratio are some of you all running on some of your mild 383 cars? My car is a really clean original resto, but I’d like to get closer to the 400 hp mark and complement with a gear set in the rear to have a bit of fun on the street. Thank you all very much in advance!!

*bogs under load; stomping it in second gear is very uneventful...

 

[Frank Mopar]

Google up cfm rquirements and you will see your 600 was about right. 670 probably wont hurt.

Need to match the carb power valve to your vacuum. Check that first

14 inital timing and 34 all in should be a start point

 

[malex]

Get an adjustable timing light and check your total advance. 34 to 36 total.

 

[Jeremy Nelson]

Thank you!

 

[wyrmrider]

Then see if the cam is not retarded or advanced too much
next time you have the plugs out do a compression check or let us know what you found last time
what ignition?
get it running right before thinking about gears and all that
can you do a stall test?
lots of manifold tests around - dual plane and 4 hole spacer and I like AVS ot TQs but get your combination working before you start making changes

 

[451Mopar]

It is pretty easy to over cam a 383, but it sounds like you have decent vacuum.
Is the 670 a Holley Avenger carb? and is it known to be good?
The avenger carbs I have used needed larger idle feed restriction in the metering block for good off-idle transition.
Likely need to re-curve the distributor for about 20-degrees mechanical advance so you can set initial around 14-16, and have total of 34-36.

 

[Jeremy Nelson]

It is pretty easy to over cam a 383, but it sounds like you have decent vacuum.
Is the 670 a Holley Avenger carb? and is it known to be good?
The avenger carbs I have used needed larger idle feed restriction in the metering block for good off-idle transition.
Likely need to re-curve the distributor for about 20-degrees mechanical advance so you can set initial around 14-16, and have total of 34-36.

Yes, I believe it’s an avenger series. I’m considering pulling it and going to a 750. I just want to rule everything out and make sure I’m not making a mistake. I have good vacuum and it idles good, bit when setting the timing at about 12-14, it feels like the cam wants more initial timing. I guess I’ll just have to keep moving a bit and see what it likes. Again, the car just bogs when you stomp it and it also smells a bit rich... not enough air flow? Too much fuel? Timing off? Just installed New champion plugs yesterday and they’re gapped at .035. Brand new points style distributor. New Taylor wire set, USA. The two carbs I have are both brand new. The 600 came with the car, was installed 5 days before I bought the car. I had the 670 but it’s about a year old and was never used. It’s just a bit perplexing that the car runs so sluggish....

 

[65Fury440]

I would work backwards on the timing for a mystery motor.
After verifying all your cylinders are firing,
set the timing up until it starts to bump back when turning over, then back it off, see how it runs,throw the light on it to see where it is, take it for a drive. (if it doesn't have some crazy high all in number)
Put a load on it gradually while driving, and listen for spark knock.
One thing to make sure is tune it to whatever gas you are going to run.
I went back and forth from 90 non ethanol to 93 ethanol, and it makes a difference.
At this point, come back and set up your idle for highest vacuum, and you have done all you can with simple adjustments.

From there, as mentioned, start to check compression and such.
Here's a kinda decent guide to read plugs
http://www.4secondsflat.com/plug_chart.html
Good Luck !!

 

[oldbee]

You said a 670 DP(double pumper?). For what ur setup is right now, I would put the 600 (vacuum sec.?) back on & get the timing right first. Just a thought.

 

[65Fury440]

The 600 will be snappier driving around, you wont need the extra CFMs until higher RPMs.

 

[Jeremy Nelson]

Thank you very much for this advice! I’ll keep working at it.

 

[Jeremy Nelson]

I

You said a 670 DP(double pumper?). For what ur setup is right now, I would put the 600 (vacuum sec.?) back on & get the timing right first. Just a thought.

I thought about that as well. I may try the 600 and see what I get. Yes, the 670 is a double pumper, vac sec, and electric choke. The 600 is a single inlet Holley 80457 with vac sec and electric choke.

 

[oldbee]

Just to be clear- a DP won’t have vac.secondaries.

 

[Jeremy Nelson]

Just to be clear- a DP won’t have vac.secondaries.

Okay, so a true double pumper is mechanical secondaries, manual choke? I’ve been told to use mech secondaries since it’s a 4-speed. Any merit or opinions on that?

 

[oldbee]

IMHO for the street manners, vac.secs. only(drivability,tunability). I have been wrong before(but only in my wife’s mind)! If ur going 1/2 street/strip then that’s a whole new ballgame.

 

[Jeremy Nelson]

IMHO for the street manners, vac.secs. only(drivability,tunability). I have been wrong before(but only in my wife’s mind)! If ur going 1/2 street/strip then that’s a whole new ballgame.

Yeah, it will be a street car only. I’m dealing with a stock 383 aside from a mild, unknown cam and it’s just running sluggish. I’ll figure it out and all I’m really after is for it to run as it should. I would like it to be decently healthy and with that mild cam I’m not sure if I should pull it and replace for a stick cam or start thinking intake, headers, etc. Maybe I’ll get it tuned in and running well, and I can leave it alone. It’s a really nice car, near show quality and all numbers matching... she just don’t run like a RR should.

 

[Jeremy Nelson]

Yeah, it will be a street car only. I’m dealing with a stock 383 aside from a mild, unknown cam and it’s just running sluggish. I’ll figure it out and all I’m really after is for it to run as it should. I would like it to be decently healthy and with that mild cam I’m not sure if I should pull it and replace for a stick cam or start thinking intake, headers, etc. Maybe I’ll get it tuned in and running well, and I can leave it alone. It’s a really nice car, near show quality and all numbers matching... she just don’t run like a RR should.

*replace for a stock cam.... not ‘stick’ cam.

 

[Jeremy Nelson]

Can anybody tell me if I go with something like an Edelbrock performer 383 intake with a Holley 750 and the stock air cleaner, will it clear the stock hood?
What about a Torker, Performer RPM, or a Mopar M1?

 

[beanhead]

Can anybody tell me if I go with something like an Edelbrock performer 383 intake with a Holley 750 and the stock air cleaner, will it clear the stock hood?
What about a Torker, Performer RPM, or a Mopar M1?

The RPM is the one that can cause clearance issues, the others you list are lower and will fit no problem (except I'm not sure about the M1)... Just my opinion but I would definitely stick to a dual-plane for your type of motor and driving. The RPM is an excellent street manifold, if you choose to run that one you may just have to get creative with a drop base air cleaner... Edelbrock's website has all the different dimensions for the different intakes as well