mr gtx
Active Member
HP manifolds were a gimmick and more for looks than for performance
Max wedge vs HP manifolds vs Headers Test!!
- Thread starter 69monaco
- Start date
70bigblockdodge
Old Man with a Hat
That's exactly what they were. Marketing 101. They look racy, they are only on HP models so they must work. Snake oil.
Spend 1/2 hr-45 min with a die grinder and some good iron cutting bits and you can make your logs work just as well.
mr gtx
Active Member
let me dig it out and show a photo. i want a lot of money, there very rare and give a great horsepower increase over the log manifolds. lol
mr gtx
Active Member
just kidding. no problem i will keep it. think it a c-body
Care to consider the older Max Wedge cast iron exhaust manifolds of the 413s and 426s? Or the Ford 390HP or 427 cast iron exhaust manifolds compared to their stock log manifolds?
What comes out the end of the manifold is not a homogenous flow, but has pressure spikes, positive and negative. The key might well be how these positive spikes interface with the negative spikes of when the exhaust valve is open during the "overlap" phase of each cylinder's valve timing?
In my orientation of things, the HP manifolds are an improvement over the log-style manifolds. How much might be open for discussion, though. Size does matter. Otherwise, we wouldn't have had them for all of these years. Marketing didn't have anything to do with the Max Wedge-like pre-cursor to the HP manifolds, as they were used on drag race cars first. AND there is something of an un-optimized engine dyno test of headers, HPs, and their pre-cursor cast iron manifolds at Nick's Garage. Neither of the manifold pairs, to me, worked as well as they might of in a better-optimized situation.
Granted, some hot rod parts were designed by sight rather than actual flow bench (which didn't exist back then as they did in the 1980s and later) flow numbers and related dynamics.
Just some thoughts,
CBODY67
What comes out the end of the manifold is not a homogenous flow, but has pressure spikes, positive and negative. The key might well be how these positive spikes interface with the negative spikes of when the exhaust valve is open during the "overlap" phase of each cylinder's valve timing?
In my orientation of things, the HP manifolds are an improvement over the log-style manifolds. How much might be open for discussion, though. Size does matter. Otherwise, we wouldn't have had them for all of these years. Marketing didn't have anything to do with the Max Wedge-like pre-cursor to the HP manifolds, as they were used on drag race cars first. AND there is something of an un-optimized engine dyno test of headers, HPs, and their pre-cursor cast iron manifolds at Nick's Garage. Neither of the manifold pairs, to me, worked as well as they might of in a better-optimized situation.
Granted, some hot rod parts were designed by sight rather than actual flow bench (which didn't exist back then as they did in the 1980s and later) flow numbers and related dynamics.
Just some thoughts,
CBODY67
Now, one thing not mentioned is flow dynamics and how it can relate to the ultimate capacity of the manifold vs engine sizing. Size matters, relatively so. As I recall, the "dump diameter" increased in the earlier 1970s from what it had been in 1966, on the normal log exhaust manfolds. With the total flow being affected by valve timing events, including valve lift. Key thing is to not overload the exhaust manifold for best results.
Perhaps it might be time for a chart of exhast manifold sizing (cross-section, runner lengths, plus "dump diameter") by casting number and application?
Just some additional thoughts,
CBODY67
Perhaps it might be time for a chart of exhast manifold sizing (cross-section, runner lengths, plus "dump diameter") by casting number and application?
Just some additional thoughts,
CBODY67
Very interesting idea. Would be interested in seeing that.
70 B Body pass / right side dump location/exhaust pipe flange was moved to clear the torsion bar better. Might have had a slight effect on flow, but probably minimal IDK.
mr gtx
Active Member
you can see what they had to do with max headers to make them flow not even close looking to the HP manifold.
mr gtx
Active Member
if i had a choice on stock manifolds i would go with the 1963 300 J exhaust more down under than sticking up. like to see what they flow. is there any testing on those ?
Pretty cool looking. Are 63 and 64 max wedge manifolds the same?
What are the ports for? To heat up max wedge long Ram intake manifolds?
Headers 22.8 HP > Magnum manifolds
Headers 20.6 TQ > Magnum manifolds
Pretty much what Doug Thorley said.
No test of logs
mr gtx
Active Member
sorry you took it the wrong way just trying to lighten it up a little.i was rough with some of my posts but was trying to get a discussion going so we all could learn something, and with other members posting there thoughts and facts.
mr gtx
Active Member
wonder why nick didn't go to 5800 rpms with the manifolds like he did with the headers.wonder if the power dropped why off after 5300rpms
That’s pretty much expected. No one is arguing against headers flowing better and allowing more breathing at higher RPM
I'll have to watch later. Traveling.
What was the main point?
What was the main point?
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