So this winter we are pulling our cats engine and turning it from a 2v to a 4v. John has some closed chamber heads he’s picking up for us (for a steal I might add), and we plan on rebuilding the whole engine with these. Right now its a 1970 351C 2v with a offenhauser intake manifold, and a Carter AFB Competition series 4 barrel carb. It’s a very clean engine, albeit a slight misfire we believe might be a head gasket issue (when we pulled the plugs all were clean except 1 which was fouled.) But regardless, we are in the midst of preparing to pull it and rebuild the whole engine (needs bronzing too).
We are torn on what kind of intake manifold to get. We are going to be using a Holley DP 750cfm carb with a four-speed toploader. Not sure on the cam quite yet. We were pretty set on a Torker II but we’ve been looking through the Mustang Unlimited magazine we have-the cougar version, and saw the Blue Thunder dual plane intake as an attractive option too.
The Torker II is a low rise single. I would probably recommend it more for a drag or HOT street oriented car, that being said the Torker II is a compromise at best (single plane, low rise). I will say that it does pull pretty well up top, but so does the RPM without sacrificing much down low. I’d say that if you are looking at a cam in the 220-240 at .050 range either would be good. 218 to 220, low rise dual plane, much above 224 at .050 and i would go with either a high rise dual plane or the Torker II, over 240 at .050 you are looking at high rise single plane territory (Vic Jr, not Torker II), lower gears, and a much higher stall speed. Of course, you have a four speed so the whole convertor thing doesn’t apply. Just remember that the cam you select, your compression ratio, and your REAL intented use, will dictate what kind of intake you need. Back in the day I saw csome machines that sounded like they would tear some ass only to get dusted by much milder combos that were built as a package.
if it were me, I would go with the dual plane. I can’t see spending the extra dime on the Blue Thunder intake unless you are trying to look stock. What Offy do you currently have? They make some pretty good, albeit expensive pieces.
I’ll have to take a look under the hood today and see. We believe it’s a dual plane, as this car pulls you along like a banshee when you tap the gas. Don’t even have enough traction right now for it lol. It makes skid marks every time you go to accelerate, you have to feather it to keep from spinning. Whatever set-up the prior owner went with, the car does have a LOT of low end torque. We have no idea what cam set-up it has either. You can tell the whole engine was redone a while back, as the repainting job was done pretty poorly.
Doubt you can tell from the picture but it’s the most stripped down picture we have (were doing a tune up on it couldn’t reach all the plugs without taking the valve covers off.
I still stand by a good dual plane intake over the torker unless you have clearance issues. Then the Torker II would be okay. I’m just making the comment that there are a LOT of dual planes that do just as well up top and pull harder down low. I’m not saying it’s a terrible intake by any means. There are just better alternatives if you have the room.
You can get a little more torque, but if you’re building a performance engine with 4v heads then you’re pretty much done with fence riding and hand wringing over low speed power. The gains up top more than make up for the minor loss of torque at lower speeds, a difference usually in single digit numbers.
As an example, the Boss 351 exists as the most powerful factory production small block of the muscle car era. It was topped with a dual plane. The number one way to get a Boss engine to perform better is to fit a single plane on it, when it comes to bolt ons.
So, you pick your poison. But it’s just an intake. If it doesn’t work for you, you get another and fit that one to the engine.
Kind of funny that we are both making points in a different direction. Just recently saw a dyno shootout, albeit with a chevy engine, but the results might be of interest. 240 @ .050 cam I believe 10:1 comp, older 220 cc intake port aftermarket heads. The results: on that engine the high rise dual plane RPM made the broadest and most power on that particular engine over the Vic JR. within the parameters that the engine was built. The big surprise was that the lowly Performer on that particular combo was within 10 hp and had a great torque curve . Bottom line: I you can make the same, or are within a couple of horse power but have a broader torque curve, you WILL be faster. Within the power range that the engine was built, the single plane made less power. If it had been built to shift a 7000-7500 rpm with a torque peak some where between 4500-5000 rpms, then the single plane would have told a completely different story. And even better, if the engine had been in a 3500 lb car, on a strip for some real world time slip testing, there would probably be even more variances, and a bigger spread between each intake. total air flow is great, but velocity is just as important when it comes to the car actually moving.
Just think about how much better a lot of things have gotten thanks to modern engineering. Dual plane intakes being one of them. If it were a drag car, with a 320 degree roller, 11:1 compression, and ported 4v heads, 4.10:1s, a 3000 stall then I would go with a BIG single plane. A street car, full interior, mild build, near or close to stock compression or streetable compression with iron heads on today’s gas, dual plane all the way. Most people don’t seem to realize that even the low rise performer was actually designed not only as a four barrel intake to replace a 2 bbl, but also as a performance upgrade to most factory iron 4bbl intakes. The numbers don’t lie, they actually do make more power than factory pieces, factory 4bbl intakes included.
