Offenhauser manifold question.
Thread Starter
Safety Car
Joined: Feb 2003
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From: St. Joseph Mo
Offenhauser manifold question.
Maybe should have posted this http://forums.corvetteforum.com/show...139&forum_id=4 here.
Le Mans Master
Joined: Oct 2002
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From: Las Vegas - Just stop perpetuating myths please.
I liked that idea too but would be more useful on a DD than a weekend cruiser/racer.
I think the concept is more for economy & street manners than performance. Only thing D. Vizard has to say 'bout that dual-port manifold is they need more refinement. I see them at the swapmeets once in awhile but i just don't have a economy application for one.
Another app might allow a large cfm mech sec carb to function on a smaller displacement eng.
But if u do try one let us know how it works for u.
cardo0
BTW i'm not surprized the C1&C2 forum dosen't have much to say 'bout non-matching numbers parts.
Not that i don't envy C2 owners. 
I just have more fun modding my C3 the way i like it. 
Another app might allow a large cfm mech sec carb to function on a smaller displacement eng.
But if u do try one let us know how it works for u.
cardo0BTW i'm not surprized the C1&C2 forum dosen't have much to say 'bout non-matching numbers parts.
Not that i don't envy C2 owners. I just have more fun modding my C3 the way i like it.
Thread Starter
Safety Car
Joined: Feb 2003
Posts: 4,068
Likes: 27
From: St. Joseph Mo
Presently have a 3883948 '68 passenger intake manifold with an Edlebrock Qjet clone on my 427. I love the driveability but would like a little more economy. That's why I thought of the dual port manifold. Since I have tiny primarys anyway why not have them feed small runners.
Whadday mean? Economy & street manners IS performance!
Whadday mean? Economy & street manners IS performance!
Last edited by 67L36Driver; Apr 2, 2006 at 07:02 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
BB should be a good test for that dual port.
Ok, read that post again and i see u do drive it daily. 
Now that i think 'bout it a BB with larger ports and greater flow rate should amplify any good improvements (or bad effects too). Since a 427" will breath 22% more air than a 350" at same rpm u should get a better signal from the added flow through the same pri's on that Qjet (well any carb for that matter) - until the sec's open (65% on a Qjet?). So i expect carb metering will improve. And with the the sec's closed u should get quite alot of resistance to reversion flow (when the intk vlv slams shut) - kind'a act like a reversion dam (same idea as they make for the exh headers), but with >50% of the area. I expect that divider will take up less flow area (proportionaly) on a larger runner size like the BB's.
Bad effects i expect when the that intake charge slow as it empties into the intk runner and fuel drops out to flow down the runner floor to the shut vlv. So some stuttering may exist at wierd times. But heck i'm just guessing here. So if u find one cheap - why try it?
Please post your results if you deceide to put one on. cardo0
Now that i think 'bout it a BB with larger ports and greater flow rate should amplify any good improvements (or bad effects too). Since a 427" will breath 22% more air than a 350" at same rpm u should get a better signal from the added flow through the same pri's on that Qjet (well any carb for that matter) - until the sec's open (65% on a Qjet?). So i expect carb metering will improve. And with the the sec's closed u should get quite alot of resistance to reversion flow (when the intk vlv slams shut) - kind'a act like a reversion dam (same idea as they make for the exh headers), but with >50% of the area. I expect that divider will take up less flow area (proportionaly) on a larger runner size like the BB's.
Bad effects i expect when the that intake charge slow as it empties into the intk runner and fuel drops out to flow down the runner floor to the shut vlv. So some stuttering may exist at wierd times. But heck i'm just guessing here. So if u find one cheap - why try it?
Please post your results if you deceide to put one on.
cardo0
