I found the cam spec card for the engine in my '69. I entered the timing events into Dyno2000 and got approx 232/238* of duration! It have 0.460" lift on intake and exhaust.
Rest of engine: Weiand 7546 single plane intake, stock 3927186 heads (2.02/1.600 valves), stock ram's horn headers. 600 cfm Holley.
Needless to say, it idles rough and has no power below 3500 RPM. And I have hood clearance issues. Would switching to a Torker II manifold help? Would the Torker II increase some low end torque? What should I look for in a used manifold? Are there any issues with “just bolting it on”?
Someday I am going to rebuild with better matched parts.
That sounds like a lot of duration for that amount of lift. Can you post the cam specs from the card? If the cam actually has 323º duration, it is much more likely the cause of your weak low end than the intake (and probably needs headers to utilize that much duration at higher rpm also). I suspect that you won't see a big difference by swapping intakes.
Re: Torker II Intake vs. Weiand 7546 (Vetterodder)
That does sound like a lot of duration for the lift.
fwiw, Ihave a huge cam in my car. 292 advertised duration with 0.516 lift.
I've got a Torker II on my car and a Performer sitting in the garage that's had occasional stints on my car. I can't tell the difference between the manifolds for low end torque at all! My car seems to run better overall with the Torker, so it stays on.
Re: Torker II Intake vs. Weiand 7546 (Vetterodder)
I agree it is the cam. The cam is way to big for stock heads and exhaust. I was thinking that if a get a lower profile single plane intake, it would work better with the heads and exhaust manifold to make up for the too big of a cam. Interesting note, the Edelbrock Torker-Plus camshaft has similar specs, I think.
I have the original Torquer which is a single plane intake like your Weiand. I find that my engine (383 stroker) really starts to kick in above the 3500 rpm range as well but it will fly up to 7000 rpm very quickly. It might be partially a combination of the single plane and your cam. Maybe look at keying in some other dual plane intakes into your DD to see if you like the results better in the low end tq. vs the higher end hp.
I was only on for a moment last night & you are getting good help here & it looked like all that was needed was the actual cam specs. You seem to grasp your situation. Since you want to try to make it "better" easily for more low rpm power, then expect you know there is a removable plenum divider plate for that manifold. Get or make one, try it & report back. Maybe it would help some. As you indicate you know for what you seem to want, expect a new cam.
oops you beat me to the post. still, what does the duration mean at .006???? :confused:
Duration at .006" VALVE lift is a SAE standard for duration and is the point where meaningful flow begins/ends. This is what works best with DD2000 for "seat to seat" specs.
The cam is a little too big for the street IMO, but isn't the Torker II a single plane manifold? That's a big problem, too. Street engines should always run dual plane manifolds as they will make more low and mid range torque, which is what you need for a driver. Also, with a single plane manifold, low speed/low load fuel metering is problematic, so you can have driveability problems that are tough to solve.
DD2000 gives more meaningful results if you use a rocker ratio of 1.44:1 for OEM rockers, which is what they actually are at full lift based on my measurements. They actually start out at 1.37:1 as the valve lifts off the seat.
As far as aftermarket rockers are concerned I don't know what they really are relative to advertised claims, but I guarantee you that, like the OEM rockers, the ratio is NOT constant, but varies with lift.
Since ddecart has already experimented with a Torker II on a large cam motor, I am thinking that switching to a Torker II can't hurt. Now I am wondering if I should just switch to a Performer manifold. The Performer manifold should give me more fuel/air mixture velocity at lower RPM then the torker II. Dave, why do you say your motor performers better with the Torker II?
I did some Dyno2000 experiments last night, here are the results:
The green dotted line is my current engine. Not too impressive. No 375 HP like the 2nd owner thought. Time to update the sig. file! :rolleyes:
1. I tried my engine with a dual plane. Positive torque gain below 3500 RPM.
2. Then I figured that my future engine will have headers, so I tried headers on my current engine. WoW. Greater torque gain throughout the entire RPM. Will header really help lower RPM torque if a kept the single palne?? :confused:
3. Headers with a Dual Plane is next. Just as I thought, same as single plane with headers except more torque under 3700 RPM with less above 3700 RPM.
4. While I am at it, when I rebuild I will install AFR 180. Torque increases when RPM is above 2500 RPM.
5. Finally, my cam for the rebuilt engine. 400 # TQ @ 4,000 RPM. LPE 74211 cam is a roller cam, this graph is with it's spec but hydrallic lifters. When I used "roller cam", torque jumps greatly!
Do you think I should buy headers and call it a day until I rebuild? Can headers be installed with the engine in the car? I think I have heard the engine needs to removed to install headers.
Also, I am not sure what my timing is set at. Any suggestions?
Install your headers with the engine in. I set my timing at 36 degrees total. IMHO at this point I would put headers on, then match your cam, intake and heads when you are ready, who knows what crank you will decide to go with by then.