newish to me built 340 valiant feels sluggish. Timing?

[jcarr210]

So I picked up a 67 valiant with a built 340 and it felt quick at the time but now seems to build revs somewhat slowly. Its not slow by any means but doesnt feel much faster than my 255hp 330i bmw. Here are the specs:

Forged bottom end (not sure in compression but enough to need 93 octane)
Lunati voodoo 60403 .494/.513
Edelbrock aluminum heads
Edelbrock airgap manifold
Street avenger 650
Tf 727
8 3/4" with 3.55

Now it came with the msd e-curve distributor and I'm wondering if that's where my problem is. Rev limit is set at 6400 and timing switches are set at 4,6 with vacuum advance hooked up. According to the chart is set at 20 degrees advance and 10 additional degrees vacuum advance that comes on relatively slowly with full advance at 3k where it does seem to get a little extra kick in the pants. I need a new timing light to see where I'm at but when I do what's a good starting point for initial timing? This is new to me so any other suggestions would be much appreciated. Thanks!

 

[gtsdude]

Give it as much initial as it will take without kicking back the starter when warmed up. Try to get total timing all in by 2000-3000 rpm, where ever it doesn't ping under load. Most small blocks like 32-36 degrees total but every motor is different. My 340 is at 18 initial with 34 total, all in at 2800rpm, no vacum advance.

 

[70aarcuda]

do not include the vacuum advance timing in your total timing...like above..as much initial as possible..

 

[Rapid Robert]

(1) set initial with "vac gauge method" (2) then weld/file slots to get 35 total (initial+slots) (3) mix/match springs staying just under the pinging point at WOT up thru the gears on your hottest/driest day (4) plug in/adj the can & want to stay just under the pinging point in everyday driving under varying load/rpm levels on your hottest/driest day (CCW with a 3/32" allen wrench slows the curve/not the total). IN ORDER & can capped in (1) (2) & (3) unless you are tuning with manifold vacuum

 

[crackedback]

(1) set initial with "vac gauge method" (2) then weld/file slots to get 35 total (initial+slots) (3) mix/match springs staying just under the pinging point at WOT up thru the gears on your hottest/driest day (4) plug in/adj the can & want to stay just under the pinging point in everyday driving under varying load/rpm levels on your hottest/driest day (CCW with a 3/32" allen wrench slows the curve/not the total). IN ORDER & can capped in (1) (2) & (3) unless you are tuning with manifold vacuum

Did you even read what this guy has for equipment, or just cut and paste?

 

[crackedback]

Pull the vacuum advance line from distributor and plug it.

Use timing light and set idle timing to 15-16* BTDC. IF RPM increases, reset it to the 800-850 range and readjust the idle mix screws. That will get you 35-36 total with the switches where they are currently set.

I might change the vacuum advance slope to something a little more mellow, higher vacuum to get max advance.

 

[AJ/FormS]

My Eddies, on a street 360, at 10.7Scr, 8.6Dcr, will pull with no perceptible difference, with power timing anywhere in the range of 30* to 34* . And does it on 87E10.It likes initial anywhere in the range of 14 to 20. It likes a mellow rate; all in by 3600ish.
It likes 20* for cold starts(no choke) . And has a sweet idle at 14*. I have a 2-stage rate of advance that kicks the first 14* to 16* in by 2600ish, and then slows down the last 4*. Thats how I get around on 87.The V-can is 20*,hooked to the sparkport and,all in by (IIRC)16inches.I bring in as quick as possible, to supplant the mechanical, for smooth,mellow cruising and part-throttle torque.Cruise timing in O/D is 2100@60mph@ about 54*All timings in.
I have a dash-mounted dial-back timing device that has a range of 15 degrees. So I can change timing from the cabin.

I wont say the 650 is too small, but when I switched to a 750DP, I noticed a marked improvement.The performance of my combo with a 600vac was, rather dissappointing.
My quench is set to about .034.The cam is an old Hughes HE3237 with 1.6 arms.
Timings are always,always, set with the V-can defeated.
I have a stick car with a 3.09low and 3.55s. Goes 93 in the 1/8. In that range,Sluggish it is not.

Having said all that, I dont think timing is your issue. But I do think, we need to get your timing squared away first.
And the very next thing would be a compression test.

That cam at 226*,234*,110LSA, should be very torquey.I know the 223/230/110, that I had (my favorite,so far)was.So if your cylinder pressure is down,this is how it manifests: soft out of the gate, and a kick in the pants,a little further down the road.The usual way around that is a higher stall TC.So lets see the compression numbers.

Timing "is set at 20 degrees advance and 10 additional degrees vacuum advance that comes on relatively slowly with full advance at 3k where it does seem to get a little extra kick in the pants."
I cant get sense out of this.
The 20*initial is good, if a little much.
The all in by 3K is probably ok with 93octane
But the 10 additional with vacuum is out in left field.

 

[MopaR&D]

I'm with AJ on this one as usual huge amount of good info. I think if you modified the centrifugal advance to be faster and more linear there wouldn't be a "kick in the pants" at 3000 rpm although you may have carb secondaries out of adjustment. Also bump up that initial timing i run 10* with the 60401 cam in a 10.5:1 360.

 

[jcarr210]

I really appreciate all the help even if some is a bit over my head. I was a fuel injected import guy for years I know I know. So after reading I'm guessing my plan is to set the initial timing and play with the distributor settings a bit and possibly get rid of the vacuum advance, check compression just to be sure of the health of the motor, and get I'm thinking get rid of those e3 plugs the car came with. Any suggestions there? Lastly I've always wondered if that 670 has been holding me back so to speak. It runs great no stumbles nothing though. Oh I don't know if it matters but it also has a jegs 2800 stall converter. Crap or not? Thanks again!

 

[crackedback]

Nobody is saying don't run vac adv, just don't time the car with it connected.

Closed chamber edes? The engine will probably like about 34-36 total, maybe less, without vac adv.. You could set the initial at 14-16. It may even be able to start at 19-20 initial (this would require changing the rotary switches) This is where I don't like the e-curve, you have to make 5* changes in the curve, no in between selections available.

Set initial timing, simple. Reset idle speed and mixture screws if it speeds up when you do this. Hook up vac adv line to dist can.

The only other change, the setting on rotary switch #1 from 4 to 0. That will slow down the vacuum advance rate.

Verify the timing without vac adv, if currently incorrect, it may drastically change the performance of your car.

 

[jcarr210]

Ok got it yeah I was confused on that. Apreciate it.

 

[crackedback]

See if the car will start when hot in the 18-20 range for initial/idle timing. If it will start OK, run it there and change the rotary switches.