Question for the more experienced.
Thread Starter
6th Gear
Joined: Feb 2007
Posts: 6
Likes: 0
Question for the more experienced.
Hey guys, im new to this site, but you all seem to have more experience than me with Corvettes. I just got some new magnum roller tip rocker arms from Competition Cams' for my 79 vette. I ordered them from an Ecklers magazine, But when i got them in the mail, I opened the box, and there was the instructions sheet, and it said that I cant use the old pushrods with the new rocker arms. So i went back to the Ecklers magazine and looked for some pushrods, but they dont sell them, and it doesn't say anything about needing new ones... so do you guys think I really NEED new pushrods, or are they just trying to get me to spend more money?
One other quick question. How much hp do I get from taking off the mufflers?
Please help
Thanks.
One other quick question. How much hp do I get from taking off the mufflers?
Please help
Thanks.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
It is a good idea for new pushrods but not always needed. The pushrod tip wear to the old rocker arms and when you have new rockers you have old pushrod tips. This will sometimes put an uneven wear pattern on the rockers and wear them out quickly. Go to one of the catolog speed shops and get the pushrods. They will be cheaper and be able to help you out better.
As far as the mufflers it depends on wha ttype are on the car. Sometimes you can lose HP by pulling off the mufflers. If you have the stock mufflers they are robbing some HP. Get a good set of performance mufflers and you will have a decent sounding car with HP to boot.
As far as the mufflers it depends on wha ttype are on the car. Sometimes you can lose HP by pulling off the mufflers. If you have the stock mufflers they are robbing some HP. Get a good set of performance mufflers and you will have a decent sounding car with HP to boot.
Instructor
Joined: Dec 2006
Posts: 190
Likes: 0
From: Henderson Ky
It is a good idea for new pushrods but not always needed. The pushrod tip wear to the old rocker arms and when you have new rockers you have old pushrod tips. This will sometimes put an uneven wear pattern on the rockers and wear them out quickly. Go to one of the catolog speed shops and get the pushrods. They will be cheaper and be able to help you out better.
As far as the mufflers it depends on wha ttype are on the car. Sometimes you can lose HP by pulling off the mufflers. If you have the stock mufflers they are robbing some HP. Get a good set of performance mufflers and you will have a decent sounding car with HP to boot.
As far as the mufflers it depends on wha ttype are on the car. Sometimes you can lose HP by pulling off the mufflers. If you have the stock mufflers they are robbing some HP. Get a good set of performance mufflers and you will have a decent sounding car with HP to boot.
what he said, will it run with the old push rods? yep. but why take a chance on wearing out your new rocker arms over some inexpensive push rods?
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
A roller tipped rocker needs proper length
pushrods to place roller on center of valve
the warning is about length.
quick test to see why;
take 1 old rocker off
dye the top of the valve stem (where rocker mates)
put new roller tip on
use orig pushrod, adjust
use starter to cycle motor (do not run !!!)
remove rollertip rocker
look at top of valve stem
is the wear (absence of dye) centered?
You might need pushrod guides also.
Please research proper rollertip rocker use.
It is hard to explain but the rocker must be paralell
to deck.
[ O ]
|| ||
_________
pushrods to place roller on center of valve
the warning is about length.
quick test to see why;
take 1 old rocker off
dye the top of the valve stem (where rocker mates)
put new roller tip on
use orig pushrod, adjust
use starter to cycle motor (do not run !!!)
remove rollertip rocker
look at top of valve stem
is the wear (absence of dye) centered?
You might need pushrod guides also.
Please research proper rollertip rocker use.
It is hard to explain but the rocker must be paralell
to deck.
[ O ]
|| ||
_________
Pro
Joined: Mar 2001
Posts: 633
Likes: 1
From: Hamilton, ON, Canada
As mentioned above, power gain depends on specifics of your situation-what type of engine, what type of exhaust pipes, what type of old mufflers, what type of new mufflers. The basic issue is: how much of a restriction is your current exhaust system providing to the flow of exhaust gases. If you're looking for a ballpark figure, as I recall from some old magazine articles, going from OEM style mufflers to free flow mufflers where the pipes don't provide too much of a restriction can release somewhere between 5 & 15 HP.
