Just reliving my childhood. I factory ordered a 1966 Valiant Signet HiPo 4sp . Loved that car and only drove it for 18 months. Looked for another for decades and finally settled on the 65. I love driving this one as well.Sounds like you have done a lot to your motor already and the more it is built up, the more you will notice the difference with the LD-4B
I took a look and decided to follow up here instead for the reason you stated. lolI started a thread on "Action Plus vs...." to see if there was an intake for my particular combo that would offer a gain. The thread left the intake subject pretty fast, but I like stuff like this. The Action plus has performed very well.
The lowest rpm I've seen was in Hot Rod Magazine, Aug. 1968 "Building Mopar 340, part 1"As you're going for consistency this is nearly impossibly to do. As soon as you WOT it, it is going where the converter flashes anyway. Doing it twice for a back to back comparison consistently would be unlikely. How long are you at WOT under 3500 RPM anyway?It would be interesting to dyno a 273 with the HP manifold vs the LD4B. (and start the readings out at 1000 rpm instead of 3000 like most dyno operators do)
Wow that's cool. That's the way to do it. Wish I was closer. I used the street dominator on my last 340. Still have it. LD340 is currently in use, and an RPM waiting in line which I expect will be better at lower rpm and part throttles due to the runner cross sections and shaping.I've got a Mustang dyno and I can do part throttle dyno pulls as well as WOT, which would be useful for really comparing the intakes. I've even got a 318 powered plymouth, but it currently has a Holley Street Dominator on it.
I am very curious to know if the LD4B is really better than the Performer, and I want to know if the LD4B is the same thing as the Weiand Action Plus, but I'm not spending $750 on intakes to find out. haha.
The LD4b works almost as well as an LD340. Been a few that have swapped them on 340-360 headed engine and the difference was minimal at best. It's a great performing intake even if it is the small port window which as I've said countless times is the BIGGEST red herring BS in the SB mopar world.
Some of the other intakes that get recommended all the time have the same port window or smaller than an LD4b.
I'm never too old to learn. Thanks Cracked!
I would imagine Edelbrock used the LD4B casting and tweaked the cores for the exhaust runners to make them 340 size for the LD340. If you have something that works why mess with it any more than you have to. Both manifolds just work!
That cam is close to the Crane Blazer that I ran in My teener, short on lift by comparison, but duration #'s are pretty close....I just bought an LD4B off ebay for the slightly unreasonable price of $250 shipped. Going to dyno test this with the Action Plus back to back on my 318 Satellite when the weather gets a little warmer.
That cam is close to the Crane Blazer that I ran in My teener, short on lift by comparison, but duration #'s are pretty close....
Yes all very interesting. Considering that Chrysler supplied single plane intakes on 273s, I'm not convince the short runners and combined plenum are always a loss at street rpms and low throttle. Keep us posted. This will be awsome.My 318 is stock other than the intake, headers, and the Summit 6901 cam, and only makes power to 4950 RPM. It can't even get to where the HP and TQ curves cross at 5252! With the low compression and crappy 318 heads, it probably won't no matter what I do.
Rob - I think we agree. My point was that people too often dismiss it for lower and mid range performance just because its a single plane. They shouldn't. I used the factory single planes as examples where the generalization about single planes is just that, a generalization. Clearly the factory didn't think it was an absolute.Mattax,
Holley street dom intakes, especially for the BB are stout intakes.
I chose the Summit 6901 for the wide LSA to keep what meager compression the 318 had and for the nitrous. Its also got a very fast (I think 34* ABDC) exhaust valve closing event to help preserve dynamic compression. Somehow, it sounds pretty badass also!
My favorite thing to do is what you are about to do. I'm tuned intoolmanmike: I have a restalled stock converter. I am sure a looser one would be better, but I drive the car a lot when the weather is nice and its fine.
Mattax: Yes, that 273 intake looks like a 4 bbl version of the factory intake that came on this 318. Obviously, this 318 single plane was not intended as a high rpm screamer as it would only rev to 3500 rpm on the dyno-LOL. I've often wondered if they did them that way for hood clearance. My LD4B and Action Plus intakes are on the way. I'll be sure to baseline the Street Dominator that is currently on the motor before installing the other intakes so we'll have a three-way comparison. I'm very interested to compare torque production between the three of them.
It's interesting that nobody sells a small-runner low-profile single plane intake and claims its a torque improvement anymore.