Inliners International Forums General Discussion Engines Offy vs. Clifford

Yesterday, a fellow L6 Camaro friend came over. He's got a 250, unmodified engine, with Clifford intake and headers, a Holley 4BBL, and electronic ignition. It's got 150K miles and still runs great. Coincidently, I visited the machine shop yesterday morning and the guy really likes the Clifford equipment.

Friend's intake...


My intake during assembly. For the time being, leaving the original exhaust manifold in place.


I've already purchased Langdon headers for this winter's build.. I like how the Clifford intake puts the carb in the preferred orientation with the throttle on the side. The carb is up and out of the way versus my make-shift cable (not shown). Plus with the Offy, I've got the base plate and a 1" riser with three gaskets to leak versus one gasket on the Clifford.

But I've already got this equipment. Do you see a big reason to abandon the Offy intake or the Langdon headers?

Thanks,
Mark

Unless you have a higher stall torque converter, low rear axle gears, 3:73's & lower.
I would not use the Clifford unless you are wanting to make more top end power & that is your goal.

For a daily driver, it's hard to beat the Offy, it just gives the carb a better signal to meter fuel better, better mileage, better throttle response & so on.

Eventually the Clifford headers will leak, typical header gasket leaks, they might crack.

Cast iron manifolds will usually last a lifetime, not have gasket leaks, will also be quieter than tube headers, (if that is a concern?)

If I were you, I would stick with what you already have, minus your carb adaptor plate.

Twisted6, AKA Larry, can make a carb adaptor plate for your Offy intake & use just one gasket also.

MBHD

Offy and Langdon all the way. The price difference alone is worth it but you also have more low end with the Offy intake over Clifford. As Hank said, the Langdon CI headers will also last longer. I hit mine with VHT ceramic coating (a whole $10 at Autozone) and they still look new.

With the carb turned, though, I found I need a return spring on mine.

You can see it here:



Tip: if you paint your intake manifold and want to get the raised lettering to stand out use a file to file away the paint.

Double-tip: Clear coat it when you're done or you'll be like me repainting the darn thing once a year...

Next time I have to remember to buy the stupid clear coat!

I really don't see why it matters. I used the clifford on my 292 and had NO issues with Anything. Weather it be low end or high end. That engine pulled and would tow perfectly. So, If I was in your place I'd keep the intake I have. There are advantages of having the clifford as you can mount the carb how you wish and also the water lines are super easy to hook up compared to the offy. For a daily driver either would be fine. Simple thing is this...the offy flows better for low end...but the clifford flows better all around. I'd get Tom Lowe's opinion on this as well as he has dyno proof. But since you have the offy...keep it. No sense is fixing something that's not broken.

A 292 actually could use a Clifford manifold more easily.
With having 4.120" of stroke , it already has stump pulling torque.
AFAIK, Tlowes engine dyno testing were not tested @ idle RPM & up.
Not a good reference IMO.

Also, AFAIK, Tlowes engine dyno testing were done @ wide open throttle, are you driving @ wide open throttle all the time?

My point is, you would need to have a running vehicle, swap manifolds & drive them on a daily basis to actually see the differences, what RPM's they start pulling good, throttle response off idle, pulling top gear @ low RPM etc.

If you are just looking to see what manifold makes more power & not by much mind you, Tlowes engine dyno tests should shed some light, but like I said, it does not give you a real world testing on a vehicle that drives on the street or at a track for that matter.

The two manifolds here are different designs, one is a higher RPM manifold & the other is almost like a stock one but can adapt different carbs to your liking.

MBHD

If you have the Offy on your engine, keep it. If you desire more power, then the Clifford is what you need. It will produce more power up at the top of the RPM range. The two different intakes were very close at lower RPMs on the dyno. Duececoupe has done testing on a car and also found very little difference on a stock engine.

Thanks MBHD, GBauer, TJ's Chevy, TLowe!

Whew! I'm not making a mistake. I'll stick with the Offy intake that's installed and the Langdon headers in the box. I bought the water plate from Tom Langdon when I bought the header.

I've sent PM to Twisted6 about the carb plates. I sure would like to eliminate my cable with brass water fittings and electrical tape. :-)

I'll post a few more questions from my visit to the machine shop.

Thanks,
Mark

When you do run the water many will recommend coming off the front of the engine, specifically the elbow going into the thermostat and somewhere around the pump.

I chose to do mine this way:





I know it looks like it's touching the headers but there's about 1" of clearance. no problems.

I tried plastic T's but they wouldn't hold up. The hoses are different diameters so I needed something I could clamp down hard on. The brass T's from Lowes did the trick nicely and I kinda like the way they look in the engine bay. Kinda throw-back-ish with the brass on the straight 6. If I had an LS in there they wouldn't fit in at all but with the 6 they somehow do.