I've got an Offy 360* that I picked up at the yards for $80, wondering if it would be a good intake for low RPM driving. From what I have heard, it doesn't sound like it, but I can't find any concrete info on it. The motor I have is built for low, low rpm power, (Crower says the cam red-lines at 4300) So I want the best low end intake to match.
I am using a Offy 2x4 360deg and it's not great down low. I'm using it in a light car with a bit of cam, which is likely a different scenario than you, however I can tell you it doesn't pull vry hard until about 2500 rpm.
Sorry I'm reporting a "seat-of-the-pants" feel and I can't be more quantitative. I have seen the Offy 360 described as a medium to high power band, although I'm not sure where I saw that.
To give the intake a bit of credit, I believe I could improve my low end response wiht a bit of igntion and carb tuning, but there is no question. It's a poor manifold, and when it coems down to it, for low rpm powwer, a dual-plane is really what you need.
Just for perspective, your intake was used on a lot of 390-428 race trucks prepared by Ford's race shop for off road racing and won time after time. Many championships were won and your part, if it is the original style, helped. Those trucks flew for their day and were tough as nails. And if you knew how to drive they came home, internally, fine.
This intake has been on the dyno, on such engines for hundreds of pulls and had excellent fuel distribution, exhaust gas temps and broad, dual plane power and a flatter torque curve. It has many favorable design features for mid and higher rpm use but with medium riser heads and CJ valves on a blueprinted engine with ported heads and the right cam, etc.
You might want a street towing, truck style mileage manifold with higher velocity low rise ports. Most vendors have one.
An old streetmaster 390 from Edelbrock might help you enjoy both worlds. Single plenum, low rise ports up high. Great torque and power. You have a lot of other choices for stump pulling, low end efficiency.
But if you were close by I'd buy your intake if it was clean. It is not a bad piece at all for it's intended use and era. You can make plenty of single 4 V power with that guy. We used to pick them up straight from Tay Offenhouser at the foundry/factory in L.A.. Never had one porosity/core shift or fit/machining problem either.
The manifold is in good condition (I just had it shaved to clean up some warp, had a few cracks welded and some heli-coils put in) The only thing it needs is paint, I painted it to match my motor and the paint didn't stick too well.
How are the stock 4-barrel intakes? I imagine they're pretty good down low with they big long runners and dual plane design. Those thing pop up on Craigslist all the time for $50 or less.
Sorry, I forgot to mention the motor is in a pickup! Definately not a fast truck, anything over 70 feels like riding a toboggan, just hold on and hope you stay in your lane! From what your saying the Offy would be better match for a hot rod, makes sense to me.
That was one of the worst intakes I tested when I did all the dyno testing for my book. It was down 40 lb-ft of torque at peak as compared to the Performer RPM on my 428CJ dyno mule (410 HP), and down 25 lb-ft on average from 2500-5300 RPM. Don't use it; there are much better choices out there...
There's the early 58-65 Iron Bird (call it the Z-code iron)
Then the 66-69 S-code iron
Then the mid-70s T-code truck iron
Any one of those 3 are pretty good for low end and you can get them for 40 cents a pound or less, try that with ground beef or potato chips!!!
The S-iron is perhaps the very best low end but they are all pretty good.
The alum Performer is slightly better than the Z, S, or T iron but I dont think it's $200 better unless U have one already.
Maybe that Offy 360 really wakes up behind a 500hp engine but note Jay's comment, it was a real dog on the dyno.
Well the Z would be any iron intake from 58 thru 65 eg c4se or c3ae or c5ae etc. They also have tall ports about 2-1/8 tall
The S would be I think any iron from 66 thru 69 casting number eg c6ae etc or even c9ze the rare one. Their ports are about 1-3/4 tall but the carb pad is about 1" higher than the Z.
The T intake are all trucks mid 70s so part number would be d4te or something like that.
Since the years dont overlap it is pretty easy to separate them.
The Z will have a port mismatch at the floor if you use mid-66 or later lo perf heads eg c6ae-u c7ae-a c8ae-h or d2te-aa. The mismatch is not a big deal but the S intake might be better if your heads are any of those.