Technical 265 Exhaust Manifolds on Dual Quad 327

I've searched around but the details of my question don't align with the old "use 55-56 SBC manifolds for fitment solutions" threads.

These manifolds would absolutely make it easier for me to clear my steering box and run my exhaust. However, my 327 is fairly stock with the exception of dual quads and I'll likely run a mild cam.

I'd love to run headers but they'd have to be custom and I'd rather spend the money elsewhere, if possible.

Here's a pic of the space I'm working with:




As you can see, a 265 manifold would drop the exhaust right into the open space.

My concern is: while the manifolds have been proven to work well on stock 327s, I'm wondering if the manifolds erase any benefits gained with the carbs and intake. Is it taking the lame way out?

Here are the headers:



I planned on running the passenger side and modifying the driver's side, rebuilding them so they look similar but they drop into that same space. I've been told that there's not actually all that much advantage to headers like these (other than looks) compared to rams horns. I really like the look and they'd look neat modified but the simplicity of the 265 manifolds really has me thinking.

What do you fellas say?

 

Compare the size of the ports in the manifolds, to the size of the ports in the heads. What do you think?

 

Look at the headers on Dean Lowes rpu, you can buy these pretty reasonable and you can drop the exhaust thru the aprons. Will fit your 60s drag vibe.

 

It will definitely be a restriction. What about a right side rear dump ram horn manifold switched to the driver's side so it dumps forward, allowing you to make the exhaust snake around the steering box? That's what I did on my 40 Ford.

This is a crappy pic of it, but you get the idea.

 

Another option, is look for C1 rams horn manifolds, typically from '67 to '72 for trucks.
On the web, but would be as much as headers most likely. Used would be worth the search.

Like Dan said above...

 

How about an 80's G body manifold.

 

I'd port match the manifolds and run them. But I'm not a fan of headers. Really a lot of hassle if it's not a real race car.

.bjb

 

Use the 265 manifolds because they have that vintage look. If it turns out to be too restrictive, you can change them later.

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Sanderson makes a set that curve forward on Dr side

 

Dan, I'd love to get my hands on one to see how well it would clear my steering box.

I've been looking locally.

 

I may have one. Let me dig in my pile o treasure....

 

265's will be fine. Might even tolerate straight pipes better for street use. Jack E/NJ

 

What about this?
1970 Chevy C-10 with a 350. I love Chevrolet’s!

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If I have one, that’s what it will look like.

 

With all of the amazing fabrication you guys have done so far, custom headers should be a no brainer. If it was a ‘52 Chevy four door cruiser I’d say WTF use those crappy manifolds, no one will see them anyway. But your competition flavored coupe needs an era correct set of headers. Even the ram horns don’t make it.
Hell, PM me and I’ll even donate the flanges.....


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Dual quad 56 Chevrolet’s used them and I used them on a 53 Chevrolet conversion to a 283 with Rochester FI and a 30-30 cam... worked for me.

 

That's very similar (if not the same mfr) to what Brzezinski uses with their Chevy II manifolds. https://www.castheads.com/chevy-ii-exhaust-manifolds/

 

Some good advice....not sure if you want to go fast are look a little like a period build. My vote is for the factory stuff 55/57.....they ran good enough in the day !

 

The Chevy II or truck passenger side manifolds are an interesting option. If any of you have one kicking around, can you pull a measurement or two for me?

It's roughly 6" from the bottom of the bolt hole to the top of the box.

 

@Johnny Gee it needs to be front drop, not rear.

 

I realize your request however looking at your top and side view it's possible?

 

I'll take a couple of detailed/clearer pics.

 

You need to fab some cool headers for it. The car is begging for it.

 

I can go dig out my 67 Nova (Chevy II) exhaust manifolds to measure for you but I'll tell you this, they are getting hard to find and when you do find them they are real expensive.
Even though the truck versions are much easier to find, the problem with them is due to constant heat/cold cycling and water splashing they are commonly found to be cracked.

 

Those engineers at GM had no idea what they were doing, obviously

 

^^^^^ I was going to mention that but worded differently. Just 7.75 cubic inches per cly more.

 

Three year old HAMB classified advertisement.
Pretty crazy money huh!

Note, look close at these photos, the quickest way to identify Chevy II manifolds are the thin end mounting flanges, they are the only ones like this.

Here is a very nice like new pair of 1964-67 chevy II nova exhaust manifolds, cleaned, media blasted, magnafluxed and have 1200 exhaust paint. I don't think you will find a nicer pair.
$475.0 plus shipping.

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I went out and looked and have the straight down dump left side off my 71 but it must have been the right side that got broken. I knew one had been broken but couldn't remember which one.

I'm just going to say that back before the mid 60's far more guys ran manifolds on their hot rods than headers.

 

I'm certainly not saying anything like that. But, there is a reason why they were run on 265s and the same GM designers planned larger manifolds as they increased CI.

If anything, it's more obvious that I have no idea. Hahaha.