Some times when I am laying on the couch looking up, the truth comes to
me..... I read all the stuff on my web page about this and wonder why it
took so long to come to me, but there it is...And Thats The Truth !!!
GMC Exhaust systems.
MANIFOLDS
You got-em, smoke-em. (military slogan from a despicable drug habit) If you
have good exhaust manifolds, resurface them, remount with copper gaskets,
and put them on with an impact wrench. Retorque them some time, if you
think of it. They worked for 30 years maybe they will work a while longer.
If you want them to last longer on our crappy gas, put in an A/F gauge and
get your carburetor fixed until the exhaust does not run lean and hot.
When the manifolds crack, go to headers.
HEADERS
When you cannot find manifolds, put on Thorly iron headers. Don't coat
them, it cost two times as much, burns off any way, and probably does not
do much for reducing the radiated heat, and cannot be proven to do much for
horse power unless you have a dyno (which we don't, and the gain is so
little who cares). Put them on with copper gaskets and an impact wrench.
Keep your old mufflers if they are ok, you will only gain 10 horse power if
you replace them with a high flow muffler and a three inch exhaust anyway,
and that is not enough to spit at. Never end a sentence with a preposition
and add some fans to draw the heat out of the engine compartment when you
stop.
MUFFLERS
When your old mufflers burn out, replace them with straight pipes and cut
in a single three inch turbo muffler in the rear (or use two up front
doesn't really matter). Keep your 2.5 inch exhaust pipe until it burns
out, you will only gain about 10 horse power if you replace it and that
will come too soon anyway. It is a little louder with a single muffler but
there is little back pressure.
EXHAUST PIPE
When the 2.5 inch exhaust pipe burns out, replace it with a three inch pipe
from the 2.5 inch Y straight pipes to the three inch muffler in the rear.
You will help the headers do their job and you will pick up a few horses.
FINIS
When you have all of the above, you have headers that won't crack, one less
muffler to worry about, a full flowing system and you may have picked up 10
to 20 horse power. Not much here to stress over. Do what you have to,
this is not going to change your life.
gene
and who cares if you don't beleve me ;>)
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
me..... I read all the stuff on my web page about this and wonder why it
took so long to come to me, but there it is...And Thats The Truth !!!
GMC Exhaust systems.
MANIFOLDS
You got-em, smoke-em. (military slogan from a despicable drug habit) If you
have good exhaust manifolds, resurface them, remount with copper gaskets,
and put them on with an impact wrench. Retorque them some time, if you
think of it. They worked for 30 years maybe they will work a while longer.
If you want them to last longer on our crappy gas, put in an A/F gauge and
get your carburetor fixed until the exhaust does not run lean and hot.
When the manifolds crack, go to headers.
HEADERS
When you cannot find manifolds, put on Thorly iron headers. Don't coat
them, it cost two times as much, burns off any way, and probably does not
do much for reducing the radiated heat, and cannot be proven to do much for
horse power unless you have a dyno (which we don't, and the gain is so
little who cares). Put them on with copper gaskets and an impact wrench.
Keep your old mufflers if they are ok, you will only gain 10 horse power if
you replace them with a high flow muffler and a three inch exhaust anyway,
and that is not enough to spit at. Never end a sentence with a preposition
and add some fans to draw the heat out of the engine compartment when you
stop.
MUFFLERS
When your old mufflers burn out, replace them with straight pipes and cut
in a single three inch turbo muffler in the rear (or use two up front
doesn't really matter). Keep your 2.5 inch exhaust pipe until it burns
out, you will only gain about 10 horse power if you replace it and that
will come too soon anyway. It is a little louder with a single muffler but
there is little back pressure.
EXHAUST PIPE
When the 2.5 inch exhaust pipe burns out, replace it with a three inch pipe
from the 2.5 inch Y straight pipes to the three inch muffler in the rear.
You will help the headers do their job and you will pick up a few horses.
FINIS
When you have all of the above, you have headers that won't crack, one less
muffler to worry about, a full flowing system and you may have picked up 10
to 20 horse power. Not much here to stress over. Do what you have to,
this is not going to change your life.
gene
and who cares if you don't beleve me ;>)
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
