Log Manifolds vs EMI etc

[raritan]

I see very few log manifolds on SBC. What are the disadvantages and advantages, if any?

[MOP]

They are a little restrictive, center riser types are better, after market being the best for both performance and the better sound.

Phil

[Cuda]

Just about everything I've read says that the exhaust is the bottle neck on making power in a boat. MOP explained the rest above.

[smoothie]

You may want to call the experts,like CMI,Stellings,GIL and a few others,most likely they will all tell you that unless you have a flame thrower of a motor,500+ hp you will only gain 5%,10% at the most hp with headers so going with different manifolds I dont think you will notice any gain,may want to look at which one will last in the long run without any leaks or reversion and good looks.IMHO! :stan:

[Cuda]

You may want to call the experts,like CMI,Stellings,GIL and a few others,most likely they will all tell you that unless you have a flame thrower of a motor,500+ hp you will only gain 5%,10% at the most hp with headers so going with different manifolds I dont think you will notice any gain,may want to look at which one will last in the long run without any leaks or reversion and good looks.IMHO! :stan:


That may be true if you have center riser manifolds and not a monster motor, but I'm sure you will find a difference between log style and good center risers even on a mild engine.

[smoothie]

That may be true if you have center riser manifolds and not a monster motor, but I'm sure you will find a difference between log style and good center risers even on a mild engine.

see attached,are we talking about this type of log style manifold?

[raritan]

see attached,are we talking about this type of log style manifold?
Yes, I would like to reduce weight in the 65 ski sporter but really dont need any increase in HP. I already have more power then the boat can handle. Log manifolds arent as expensive.

[smoothie]

Yes, I would like to reduce weight in the 65 ski sporter but really dont need any increase in HP. I already have more power then the boat can handle. Log manifolds arent as expensive.

Then go for it,I've looked high and low for the best manifold and havent found anything yet to change my mine over my logs,in fact the way the logs are designed with the the slope down from the heads and then the 12" risers and finally the water exiting out at the exhaust tips,you pretty much dont have to worry about reverson or springing a leak,plus I like the looks,keep an eye on e-bay,I see em sometimes go for a good price.IMHO :stan:

[Dennis Moore]

I can set you up with some great aluminum manifolds for weight savings and increase your performance over the logs.

When I was writing my book I included some drawings of manifolds with, what I considered to be, some important features that every manifold should have. The folks at GLM had been considering getting into the replacement exhaust manifold business for some time and contacted me about my manifold ideas. They consulted with me and utilized most of these ideas in the design of their replacement manifolds.

They are cast at a high tech foundry overseas using the modern "lost foam casting technique" and are of excellent quality. This new casting technique provides excellent casting thickness uniformity (no core shift) with no porosity problems. The process also allowed us to divide the cylinders exhaust pulses with separate runners for the outer cylinders. Because of the low rejection rate of the modern casting process the price is very reasonable (don't have to pay for all of the bad ones to be melted down and recast).

We sell the small block and big block Mercruiser manifolds in cast iron or aluminum. The cast iron manifolds are dipped in hot galvanizing before painting. The aluminum manifolds are available with black powder coating or are available raw (to be polished by your polisher).

Dennis Moore
626-357-3573
www.mooreperformance.org

[smoothie]

I can set you up with some great aluminum manifolds for weight savings and increase your performance over the logs.

When I was writing my book I included some drawings of manifolds with, what I considered to be, some important features that every manifold should have. The folks at GLM had been considering getting into the replacement exhaust manifold business for some time and contacted me about my manifold ideas. They consulted with me and utilized most of these ideas in the design of their replacement manifolds.

They are cast at a high tech foundry overseas using the modern "lost foam casting technique" and are of excellent quality. This new casting technique provides excellent casting thickness uniformity (no core shift) with no porosity problems. The process also allowed us to divide the cylinders exhaust pulses with separate runners for the outer cylinders. Because of the low rejection rate of the modern casting process the price is very reasonable (don't have to pay for all of the bad ones to be melted down and recast).

We sell the small block and big block Mercruiser manifolds in cast iron or aluminum. The cast iron manifolds are dipped in hot galvanizing before painting. The aluminum manifolds are available with black powder coating or are available raw (to be polished by your polisher).

Dennis Moore
626-357-3573
www.mooreperformance.org

Hello Dennis,
First of all I want to thank you for your performance book on BBC,its been good reading material on these cold winter nights and could you post some performance no's on your manifolds vs logs,also I have logs now so if I use your manifolds do you sell different risers to get them hooked up to my lower exhaust tips.Thanks! Rick

[Rootsy]

Maddog you read my mind...

Root - Show Me The Numbers!