• Spank
  • Utter Madman
  • Offline
  • From: Escondido, CA
  • Registered: 2009-06-10
  • Posts: 3,074

Topic: BSO / Olds 307 manifolds

I'm looking to help address what seems to be an exhaust clearance problem. The stock exhaust manifolds have a crossover tube beneath the engine and the passenger side collects it and then shoots it out rearwards. This won't work with the firewall clearance. Is there an alternative Oldsmobile pattern exhaust manifold that has it coming down instead of pointing rearward and without the crossover pipe? The alternative is to cut the rear facing flange off short and weld it up (yea, welding cast iron) and using the crossover portion as the exhaust exit.

Any budget-friendly suggestions?

Spank's Website

2 Reply by Parkwod60 (edited by Parkwod60 2012-06-11 02:21 PM)

  • From: Van Nuys, CA
  • Registered: 2011-02-11
  • Posts: 2,609

Re: BSO / Olds 307 manifolds

Now, I am a little rusty on my Olds specifics, but if I'm not mistaken the 307 is basically the same as all the other Olds motors, I mean there is no big block small block, they are all the same.

You have these here, right:  http://www.ebay.com/itm/Exhaust-Manifol … mp;vxp=mtr

How about these?: http://www.ebay.com/itm/1974-442-CUTLAS … mp;vxp=mtr

These any better?:  http://www.ebay.com/itm/NINETY-EIGHT-CU … mp;vxp=mtr
http://www.ebay.com/itm/80-81-83-84-NIN … mp;vxp=mtr

Olds motors were in all the GM big wagons from the mid80s-1990, but I think they all had that stupid manifold. Small Block Chevy "block hugger" headers in mild steel start at less than $60 on ebay though, they should be close to the right size, and are easy to weld. Cut the flange, put the bolt holes where you need them to be and weld it all back together.  The 3-1 I made for my straight six lasted all weekend at Sears point and I am an admittedly bad welder.

Olds header
http://img.auctiva.com/imgdata/4/8/2/3/4/5/webimg/509229645_tp.jpg

Chevy header
http://mysite.ncnetwork.net/partsexpress1/000_8845.jpg

Constructor/Owner/Driver - Billy Beer Ford Futura

Parkwod60's Website

  • From: Yorba Linda, CA
  • Registered: 2010-12-19
  • Posts: 251

Re: BSO / Olds 307 manifolds

Can you turn them around, swap them left for right, and run the exhaust out the front?
(or throw some 180°'s on them to get the smoke going the correct direction again..?)

  • From: Elburn, IL
  • Registered: 2010-12-16
  • Posts: 2,404

Re: BSO / Olds 307 manifolds

jiggermyster wrote:

Can you turn them around, swap them left for right, and run the exhaust out the front?
(or throw some 180°'s on them to get the smoke going the correct direction again..?)

I like the way this guy is thinking!  Very LeMony!

A&D: 2011 Autobahn, 2012 Gingerman, 2012 Road America, 2012 Autobahn II
Building a car for the second half of 2013 under the auspices of:
Sir Jackie Stewart's Coin Purse Racing
http://www.facebook.com/#!/SirJackieSte … urseRacing
  • Spank
  • Utter Madman
  • Offline
  • From: Escondido, CA
  • Registered: 2009-06-10
  • Posts: 3,074

Re: BSO / Olds 307 manifolds

That option was explored and can't happen.

I like the idea of converting sbc headers into something that will fit the olds pattern. I'll see what I can find.

Spank's Website

  • From: Van Nuys, CA
  • Registered: 2011-02-11
  • Posts: 2,609

Re: BSO / Olds 307 manifolds

I was skeptical myself about making my own individual header flanges for each port, but I just used 1/4" steel plate with a 1 3/8" hole drilled in it. Make sure they don't hit the frame or cross-member when the engine torques over. Dump it into a flex pipe and you're done.

Don't know if you saw the pictures I posted of mine, but I didn't have a bender, I just cut and welded about 4 pieces for each cylinder. Lasted 1 race so far, no issues.

Constructor/Owner/Driver - Billy Beer Ford Futura

Parkwod60's Website