Corvette manifolds on a 350 crate - Impala Tech
Performance Our High Performance Area

 
LinkBack Thread Tools
post #1 of 10 (permalink) Old 02-01-2011, 09:58 AM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
Corvette manifolds on a 350 crate

Hey guys, I'm looking to replace my current manifolds that were mounted on a 305 that I just swapped for a 350 in my 62. I was planning on installing headers but after talking to a few people it sounds like a bad idea due to them warping and leaking over time. It was suggested to me to run corvette manifolds which would perform like headers minus the headaches of leaking and warp. If I go this route...what do I ask for when looking to buy a set? Also what mufflers would work well with corvette manifolds?
RMendez is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 02-01-2011, 11:00 AM
Moderator
 
Join Date: Jan 2006
Posts: 12,383
 
First headers are not as bad as you think. I have been using them since Jerry Stahl first got the bright idea. Biggest cause of problem with headers is the bolts work loose. Once loose you get warping and exhaust leaks. So you either always are retightening them, or you fasten them in place permanently with a Stage Eight header bolt (or a similar product).

Corvette manifolds are 2-1/2 inch Ram's Horns (as compared to the 2 or 2-1/4 inch Ram's Horn manifold used on the production car. Even though the Ram's horn is a better breating manifold than a log manifold as used on more modern cars). It will not work as well as even a set of shorty block hugger headers do at seperating the exhaust pulses to prevent reversion of the exhaust gasses. That means you are leaving 15 to 25 "free" horsepower on he table from using a long tube header and a free flowing exhaust system.

If you are interested in cast irn manifolds because they are quiter than thin tube headers, that is a different argument. In that case I would recommend you look as Sanderson's cast iron block hugger "headers".

Big Dave
Big Dave is offline  
post #3 of 10 (permalink) Old 02-01-2011, 11:24 AM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
Quote:
Originally Posted by Big Dave View Post
First headers are not as bad as you think. I have been using them since Jerry Stahl first got the bright idea. Biggest cause of problem with headers is the bolts work loose. Once loose you get warping and exhaust leaks. So you either always are retightening them, or you fasten them in place permanently with a Stage Eight header bolt (or a similar product).

Corvette manifolds are 2-1/2 inch Ram's Horns (as compared to the 2 or 2-1/4 inch Ram's Horn manifold used on the production car. Even though the Ram's horn is a better breating manifold than a log manifold as used on more modern cars). It will not work as well as even a set of shorty block hugger headers do at seperating the exhaust pulses to prevent reversion of the exhaust gasses. That means you are leaving 15 to 25 "free" horsepower on he table from using a long tube header and a free flowing exhaust system.

If you are interested in cast irn manifolds because they are quiter than thin tube headers, that is a different argument. In that case I would recommend you look as Sanderson's cast iron block hugger "headers".

Big Dave
So if I understand you correctly, as long as I'm constantly checking the header bolts to make sure they are tight I should be ok...or if I use the stage 8 bolts as you suggested I shouldn't really have any issues? I'm not looking to spend a lot of cash, but I did notice that Hedman Headers have a "street" version from summit racing that go for about $180.
http://www.summitracing.com/parts/HED-68230/
RMendez is offline  
 
post #4 of 10 (permalink) Old 02-01-2011, 12:52 PM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
RMendez is offline  
post #5 of 10 (permalink) Old 02-01-2011, 02:51 PM
Moderator
 
Join Date: Jan 2006
Posts: 12,383
 
Header bolts work loose because of the constant heating to 1400 degress and then cooling down to ambient temperature. The constant expanding and contracting causes the bolts to back out of the threaded hole. So if you check them monthly or tie them down so they can not rotate, your headers will stay put.

With headers you get what you pay for. They are welded by the same robot so the difference in price reflects how closely they are designed to fit your car. It is the fit you are buying, as all are made out of the same material with the difference in length of the tubes equalling about at most $40. It is all of those bends that are required to fit a long tube header to your chasis that you are paying for. So expect to pay $3500 for a set of custom made equal length long tube tunable headers for a race car with an unusual motor or placed were the factory didn't put it, and about $150 for a set of universal shorty block huggers that you will have to figure out how to mount your alternator to.

Big Dave
Big Dave is offline  
post #6 of 10 (permalink) Old 02-01-2011, 03:29 PM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
Thanks for all the info....just need to decide on what I want to do.
RMendez is offline  
post #7 of 10 (permalink) Old 02-01-2011, 03:56 PM
Moderator
 
Join Date: Jul 2009
Location: Canada
Posts: 1,391
 
No problem to use headers on a street car. They will outperform manifolds by a large margin. Whatever headers you buy, have them ceramic coated. They will last forever, and keep underhood temps down.

Two doors, four doors, wagons, and ragtops.
jayoldschool is offline  
post #8 of 10 (permalink) Old 02-01-2011, 04:30 PM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
Quote:
Originally Posted by jayoldschool View Post
No problem to use headers on a street car. They will outperform manifolds by a large margin. Whatever headers you buy, have them ceramic coated. They will last forever, and keep underhood temps down.
I'm reconsidering the headers idea...I just may pull the trigger on a set and apply what you guys have said below.

Any good suggestions on mufflers??
RMendez is offline  
post #9 of 10 (permalink) Old 02-01-2011, 05:27 PM
Moderator
 
Join Date: Jul 2009
Location: Canada
Posts: 1,391
 
Mufflers are really personal preference. Some love Flowmasters. I think they sound like crap. I like the smooth rumble of a turbo-style muffler. Others think that is too quiet. I've tried everything from Cadillac silence, to muffler delete straight pipes. Everything has its place. Pick a sound you like and don't let someone else decide for you.
jayoldschool is offline  
post #10 of 10 (permalink) Old 02-01-2011, 06:25 PM Thread Starter
Member
 
Join Date: Sep 2010
Location: Temecula, CA
Posts: 69
 
Quote:
Originally Posted by jayoldschool View Post
Mufflers are really personal preference. Some love Flowmasters. I think they sound like crap. I like the smooth rumble of a turbo-style muffler. Others think that is too quiet. I've tried everything from Cadillac silence, to muffler delete straight pipes. Everything has its place. Pick a sound you like and don't let someone else decide for you.
Sound advise! Thanks!
RMendez is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome