Road Runner Nest

Hi guys,

I would like to ask your advice on how I should continue whith my Roadrunner project. I´m a real novice on engine fixing.
I don't have all info on the engine which complicates things a bit.

Here is what I know:
1971 440
Holley Street Dominator single plane
Speed Demon 750 Vacuum sec.
Hooker Super Comp. Headders
Mopar electronic ignition, silver box
New Aluminium roller rockers

I dont know the cam spec. but its "hot-ish" and the stall converter is quite high RPM too.

Now, In order to set the timing and advance I have a few problems:
1: I don't know how much centrifugal advance the distributor delivers and at what Rpm. I think it's a new Mopar Performance distributor, it's got the black cap. and vacuum advance too. Is it possible to find the spec. by a number on the distributor or do they always make a certain degrees advance?

2: I almost get no vacuum at idle and therefore the vacuum advance might not be effective at all. Will the Mopar Dist. work properly if I just Plug the vacuum canister?

3: Will the Mopar Performance distributor give me enough advance at the right Rpm without the vacuum advance connected too?

4 I have thought of getting a MDS Ready-to-run distributor and just adjust the centrifugal advance to give me a advance total of 38 degrees at 3000 Rpm.
This I think would be the easy but expencive way, right!?

I hope someone can point me in the right direction.

thanks guys,
Capsule

well, if you have the MP set-up, you should be alright - it should have a performance curve in it already. if you want to set your advance by a higher rpm, you should wrap your balancer with timing tape, rev motor up to the RPM and turn distributor accordingly (that's the only way i can think of doing it). However, setting your timing off of a higher RPM may make getting the motor started a bit harder. I set mine at 10 degrees BTDC at idle with the vacuum advance disconnected. I don't know if this helps you or not

O.K... 1. Single plane intake: What rear end gears do you have? Single plane works best with deep gears (high 3"S and 4"s) like 3:91, 4:10, or even 4:30 or 4:56.
2. Vacuum secondary 750: Carb is a decent size for application. Bordering on too big ( depending on a lot of things ) and primarily used on automatic transmission cars.
3. Super comp headers??!! Try and give me your best guess on the primary tube size and length, fenderwell exit (did you have to or are there holes cut in the fenderwells to install them?)
4. Does the ignition box still work? The silver or "chrome" box used with suppression core/resister wires lasts about 3 hours. The solid core wires tend to annoy law enforcement types with all the radio interference.
5. Roller rockers. Can't go wrong here BUT correct pushrod length, and constant adjustment (while fun) affects performance.
6. Gas in the U.S. is awful, it has no power anymore. I do not know what kind of gas you get there but most of us here have had to lower compression ratios to avoid engine damage (9:1 max on pump super). 38 degrees may work on a full race Hemi w/racing fuel but probably not on your 440. Try 36. You want the most with no pinging and of course all the timing marks must be verified mechanically by careful measurements. I would like to see your car and hear back from you, best of luck, Elvad. PM me anytime P.S. its vacuum 'retard' and is for starting/idle only.disconnect and plug the vacuum line to the distributor for timing and hold the motor at about 2500 and you have full mech advance from distributor. Stand clear of the fan!

Hi Elvad,

I have gotten a bit further with my car. I did some research on the net and actually got hold of the previous owner in the US. I got some info on the motor and some pointers on setting the timing. It actually runs pretty good now! He didn't use the wacuum retard since the motor makes close to no vacuum at idle, so I plugged it off too.

The rear end is a 4.10 Suregrip, and the car has a 727 Auto trans btw.
I havent measured the headders but they don't go through the fender wells, the go under the car and exit out back like original.
Anyway, thanks for the reply.

I hope to have the car out running soon.

Capsule

Cool..I'm glad you now realize that the vacuum line to the distributor is manifold(NOT PORTED!!) vacuum and for idle and starting only. At full throttle there is NO vacuum. Hence, no "vacuum advance". The vacuum supplied to the distributor is only at idle and only FOR idle and starting. Time the engine with a timing light, timing tape, the vacuum line disconnected and plugged, at 2500+ RPM at 36 degrees BTDC (38 is a factory spec that never works except maybe on a Hemi) Would like to see a picture of your car.

Dude,its a vacuum advance check your service manual!

No vacuum at idle is impossible,if the engine is running its pulling some vacuum.the reason it does not show at the vacuum advance is the line is tapped in the carb above the throttle plates and will only pull vacuum when the throttle is opened.You can run the engine without advance but it will be a dog.

No vacuum at full throttle? this is wrong,how do you think the gas gets from the carb to the cylinders?

Now back to the original question:
It would be best to have a full mechanical advance distibutor,I like to have full advance by about 2000 rpm

750 carb: great choice, only double pumper would be better.

Hooker super comp headers:1 7/8 or 2 inch pipes(depends on wich ones you have)another great choice.Use some nice free flow mufflers and big pipes.

4:10 rear end:awesome

Sound like you got all the right parts,get the timing straightened out and you should have a real tire burner.

Hi guys,

thank you all for your comments.

The motor is now running pretty well. I need to take it for a test run soon, just changed the gear oil/filter.
I uploaded two photos of the car on my blog: http://www.mollers-cars.blogspot.com/
Capsule