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Author Topic:   manifold questions
neil rucker
Dirt Forum Champ
Total posts: 799
posted March 15, 2003 09:00 PM  
in need of cast iron exhuast manifolds for pure stock racer. BREZENSKI stuff is ilegal and out of my budget price wise. my question is what do i need to look for? vette manifolds are non existant around here. what are my other options? how do they compare? how well do they work? do i need to run pipes off of these? what size/shape? how long? crossover or not? any help would be greatly apreciated. thanks. neil

teamstertom
Dirt Maniac

Total posts: 149
posted March 15, 2003 09:07 PM  
Cast center dumps,if legal at your track,are always on ebay. Read the add to make certain what the dia. of the exhaust is. With a little time,a die grinder,good dust mask.....a fine race part can be created.

neil rucker
Dirt Forum Champ
Total posts: 799
posted March 16, 2003 09:03 PM  
need more info. thanks, neil

rico 08
Dirt Forum Champ
Total posts: 1139
posted March 16, 2003 09:17 PM  
The stock corvette style can still be bought new from gm i beleive they are about 110.00 per side.

teamstertom
Dirt Maniac

Total posts: 149
posted March 17, 2003 08:26 PM  
Go over to ebay motors,go to parts,go to exhaust,enter chevrolet and exhaust manifold will come up of all kind. The opening sizes of the rear exhaust do differ in size, Some of the higher performance manifolds have larger exit sizes. What I meant by using a die grinder was to open up and clean up around the ports. I have read that some racers are using exhaust manifolds from 88-89 Chevy pick ups. I am unclear about these,so I can not comment on these.

Slam_Shifter
Dirt Full Roller

Total posts: 53
posted March 19, 2003 09:27 PM  
I beleive 70's chevy pick up trucks also came with center dump manifolds. I have a set of them and a set of vettes. The ones from the truck are smaller I.D. on the outlet side and the ports are also a touch smaller. But they should be fairly easy to find in the bone yard and with a little massage work and creativity could be made into a pretty decent cast iron piece. I believe mine came off of a 1972 fullsize with the chevy 307 and a manual tranny in it.
Just something you could check into. But there are probably easier options the guys on here would know about. Also you can still buy new ram horns from chevy as the post above stated.

Slam_Shifter

atlapp
Dirt Roller

Total posts: 8
posted April 05, 2003 06:24 AM  
neil we recently discovered that larger dumps don't always mean more flow. we tested 4 different sets on our motor on a dyno machine and the smallest appearing set actually flowed better, by the way they came off a late 76 model pickup.also check out a company dirtpromufflers.com

flanndad#17
Dirt Full Roller

Total posts: 59
posted April 06, 2003 08:26 PM  
What center dumps are you people talking about?
I'm setting up a GM Metric and had to use angle center dumps, because to straight center dumps would have went straight into the crossmember. But the angle's are going to take a good muffler man to clear the starter, oil filter, and clutch linkage?
Which one's does everbody use?
And do you have to do anything special?

powerglides
Dirt Freak

Total posts: 374
posted April 07, 2003 06:29 AM  
I use "97" Chevy pickup on a metric chassis they have 21/4" outlets. They flow great.

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