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Technical Driver's side exhaust manifold SBC in Shoebox Pic's please?

Discussion in 'The Hokey Ass Message Board' started by CJ101, Aug 22, 2021.

  1. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    Hello. It's been discussed a bunch on here over the decades. I have to have read all the threads! There seems to be no clear solution to a driver's side exhaust manifold on an SBC swap into a Ford Shoebox. I have a 51 Ford Deluxe. Right or wrong I used the Jamco mounts. I've coupled my little 305 to a T5 and its all in. I had to raise the tunnel a couple of inches, make a simple custom transmission mount and put a small notch in my fire wall to clear the distributor. Now I'm onto exhaust. I think the reason there is no clear solution is that depending on what mount kit (or custom) you use, what transmission and what frame you have, made on what day in what year the engine is forward or backward by an inch or so each way. Mine looks like there is no way a Ram Horn will work, as the steering box is lined up on center-ish. I tried a rear dump off an 88 Chevy 1500 and it is too thick (sticks out too far from block and interferes with steering shaft) I like the idea of using the passenger manifold backwards on the driver's side (currently mocked in in pic below). My question is do you wrap the exhaust under the cross member? Is this now the lowest part on the car? My car is not dropped but maybe someday I'd like to. Or do you wrap the exhaust around the front of the engine like the flatty and squeeze it by on the passenger side? I would really appreciate feedback from anyone that has done this. Especially pics! Thanks

    upload_2021-8-22_11-45-28.png
     
  2. Have you looked at 55-56 Chevy log manifolds ? If it clears it should be fine on a 305.
     
    jimmy six and dan c like this.
  3. Would a 265 manifold give you more options. How about a R/H truck rams horn; the one that angles forward.
    Oops; Steve types faster than I do.
     
  4. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    I have looked at log manifolds and have a couple book marked. My worry is one of the best things about the 305 is it's low rpm torque and from what I have read, keeping back pressure on the exhaust manifold is a good thing. I believe the log manifolds are high flow?
     

  5. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    I'm open to any option, its just really hard to gauge what will actually work until it arrives and you test fit. That gets expense with shipping up here in Ontario! I already now own a Chevy 1500 manifold. :) I just can't tell if the ram horns hug the block enough that they would clear the box. That's why I'd love pics of one others have done. I do keep an eye on Facebook marketplace. If I see a cheap ram horn that looks like it will work, I'll give it a try.
     
  6. buds56
    Joined: Dec 9, 2004
    Posts: 189

    buds56
    Member

    Here is a pic of a mid 80's Chevy truck manifold, I believe the Malibu had a similar one.
     

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  7. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    Actually the log manifolds I was searching were not OEM. If the below are actually mid 50's, they may work, allowing me to scooch a pipe by between cross member and steering box.

    upload_2021-8-22_13-22-1.png
     
  8. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    This is the left side exhaust that came with the motor. Originally its an 88 Camaro motor but this is not an 88 Camaro exhaust manifold. Anyway, after spending the afternoon thinking about this, I'm tempted to chop the flange as shown and weld it back on angled with some stainless mig wire. It would then clear my steering box. I'm just not sure what mates to that type of three bolt flange?
    upload_2021-8-22_14-14-9.png
     
  9. trollst
    Joined: Jan 27, 2012
    Posts: 2,068

    trollst
    ALLIANCE MEMBER

    Some years chev pickups came as you're gonna cut this one, they dump at the rear, dime a dozen in the scrap yards.
     
  10. X-cpe
    Joined: Mar 9, 2018
    Posts: 1,250

    X-cpe

    Had an OT Chevy P.U. with a cracked exhaust manifold and didn't want to spend $50.00 at the junkyard. Beveled back the edges and bolted it to an old head. Tacked the top, and when I tacked the bottom it popped the top tack. Nothing to loose. Cranked the Mig up to fry and gave it one pass all the way around. (.030 steel wire) Still holding 10 years later when I sold the truck. Tried it on a buddies Ford manifold and all it would do was spit, fart and pop. You can use the removed section to try out the type of wire that will work best.

    Google '3 bolt exhaust flange', large selection.
     
  11. Those are 55-56. They have smaller passages so they arent high flow. Most 305 heads arent much better than the 265 so its kind of a match. Their a problem solver more than anything else,but I have seen them on 350"s.
     
  12. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,950

    Blues4U
    Member
    from So Cal

    I don't know about the good low end torque from a 305, but the idea of back pressure on exhaust system being good comes from a flawed understanding of engine tuning and exhaust flow. I'm no exhaust flow expert myself, but this urban myth has been busted for decades, yet it persists. No back pressure is good, ever. Velocity is what is important, getting the speed of gas flow tuned to the RPM you want the engine to make power is what is important. This may be what you're thinking of, but back pressure is not velocity. Back pressure is bad, always. High velocity at the right RPM is good. And I don't think any stockish cast iron exhaust manifold flows well enough to kill velocity at low rpm.
     
    ottoman and dirty old man like this.
  13. I usually just burn a flange out of 1/4" plate, drill the three bolt holes, and make round hole to fit whatever size pipe you are using and weld the tube in. The only thing I do different now-a-days is to coat the gasket with red silicone.
     
  14. This pic is of a passenger side G-body exhaust manifold off a 305. Wondering if this might open up some options for pipe routing. To be clear, I have not done the swap so have no experience. This manifold, when mounted on the drivers side, may interfere with your alternator, power steering, or air con due to how far forward it dumps ... it also may not. Flange uses two bolts but the factory installs a heat riser between the manifold and the pipe.

    Where in Ontario are you?

    [​IMG]
     
    Last edited: Aug 23, 2021
  15. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    Yes, that is basically the current right side manifold I have. I have mocked it up on the driver's side pointing frontwards. I don't have power steering, so there may be room to come off it and down across the front of my cross member, then up on the right side of the engine and maybe fit it between oil pan, current exhaust manifold and engine mounts. There is no room to try to wrap it backwards and stay on the left side of the engine, unless I drop below the cross member, which seems sketchy. I'm going to try and get a better feel for this tonight. I'm just on the outskirts of Ottawa.
     
  16. If you look at the G-body exhaust manifold compared to the one you have pictured earlier in the thread, the G-body manifold sits a lot higher on the engine so it may actually be possible to 'wrap it backwards'.
     
  17. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    Thanks for the input. In the spirit of closing the loop on this thread and maybe being some help to a future SBC into Shoebox swapper I'll summarize what I have done. I actually found google image pics of the G body exhaust manifold, log manifolds, ram horn exhaust manifolds and a late 80's Camaro exhaust manifold and printed them out to scale and test fit them. None of them were going to work or not easily anyway. So, I started looking at the manifold I had, which seems to be an early 80's Camaro manifold. It was basically up against the steering box and one of the bolts had an interference with the steering box. I read some other threads about people having no issues with running the exhaust real close to the steering box as long as it was not touching. So, I supported the engine with my lift and loosened the Jamco mounts and used a crow bar to push the engine to the rear of the car picking up about a quarter inch. Then I turned some Aluminum 1/4" spacers and set them between the engine mounts and block (pic below) and added a quarter inch shim under the trans mount. Now, I believe I have just enough room to get a custom curved downpipe in (other pics below)!

    upload_2021-8-28_16-18-17.png

    upload_2021-8-28_16-5-2.png
    upload_2021-8-28_16-19-21.png
     
    williebill, '51 Norm and irishsteve like this.
  18. '51 Norm
    Joined: Dec 6, 2010
    Posts: 748

    '51 Norm
    Member
    from colorado

    Did you raise both sides of the engine? Would you gain a little more space raising only the drivers side (tilt the engine)?
     
  19. This whole thread is another wives tale of the sbc dropping right in. :confused:
     
  20. That would kick the outlet flange closer to the steering box.
     
  21. '51 Norm
    Joined: Dec 6, 2010
    Posts: 748

    '51 Norm
    Member
    from colorado

    No such thing as a bolt in. I once put a Pontiac engine in a Pontiac, it was a nightmare.
     
  22. jimmy six
    Joined: Mar 21, 2006
    Posts: 10,007

    jimmy six
    ALLIANCE MEMBER

    Since some in our midst are calling 55-57 Chevrolet’s a “shoebox” this must all be moot.
     
  23. CJ101
    Joined: Apr 20, 2021
    Posts: 30

    CJ101
    Member

    I can definitely say from my experience that the SBC does not "drop right in" to a Ford Shoebox. But I regret nothing! It was a bucket list item to swap an engine and I'm having a blast. I guess like any hotrod project, you get used to every single little thing being an ordeal, not just the SBC swap but the fact that it was a 70 year old high mileage worn out car and everything needs fixing. The only easy thing that I got lucky with was the fact that the existing emergency brake system was in good working order and connected right up to my narrowed Ford 8.8 with zero mods. That was just last evening that I discovered that.
     
    jimmy six likes this.
  24. I knew you could do it cause I knew a guy who did it back in 1971.Its just a matter of finding problem solver parts,and there are more options today then there were 50 years ago.
     
  25. Ericnova72
    Joined: May 1, 2007
    Posts: 477

    Ericnova72
    Member

    If you have the room on the other side, did you consider offsetting the engine and trans in the chassis??

    Chevrolet did it OEM Factory with the Big Block in '67-69 Camaro/68-72 Nova chassis, for exhaust manifold clearance to the steering box.
     
  26. jimmy six
    Joined: Mar 21, 2006
    Posts: 10,007

    jimmy six
    ALLIANCE MEMBER

    Yep same for the 56 cables. I only had to drill the cable hole to 9/16” on the 11” drum backing plates from the F-150 11” drum brakes I used; too bad I didn’t figure that out until the 2nd side.
     

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