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Race Car Fabrication There is a lot of cool fabriaction going on the race car industry, show us what you got.


Race Car Fabrication There is a lot of cool fabriaction going on the race car industry, show us what you got.

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Old 12-16-2015, 01:40 PM
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Graham08 Graham08 is offline
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6=8? Chevy 250 Inline 6 Headers

A good friend of mine is in the process of putting together a "vintage" car by hanging a '38 Chevy body on an older dirt late model chassis. He scored a hopped up 250 Chevy inline 6 for cheap that's going to power it. I got the call to build a set of pipes for it, starting with some stubs off the flange to allow the car to get built. Once it's near completion, the whole car is coming over to my shop to finish the header job.

The challenge with this combination is the clearance for the middle four pipes to the intake. This is a Clifford intake that takes a Holley four barrel...unfortunately it comes straight off the head, meaning the pipes have to make an immediate turn down, like this:



I made another press tool like I showed in my sprint car thread to form the ends of the pipes to be rectangular. It was a bit of a compromise between the center and end ports, which are two different sizes meaning I got to grind and fit the flanges to the pipes. I had to cheat the first transition piece into the head, and cheat the intersection between it and the first bend to get a reasonable air gap between the pipe and the manifold.

Here's the view from the top side:



I'm using 1-5/8" x 2" CLR bends for this project.

Here is one of the end pipes. They are much more straighforward because there is all kinds of room to work with. I did purchase a set of 1-5/8" tacking clamps which I'm sure will pay off later on when I'm finishing the full headers.



I got all four of the center pipes to line up pretty close:



I see some header wrap in the future to try to keep from heat soaking the intake too badly.

Phase 1 wrapped up:



I may have to reroute the pipe for #1 cylinder because it interferes with the alternator...but he also has a different alternator bracket that may move it out of the way. Fortunately, I only tacked everything in the event changes are necessary.

Stay tuned for the next episode: "The buzzin' half dozen!"

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Old 12-16-2015, 05:03 PM
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Yes, I know is too late, but I would have gone 1.5" tube out and down about +/-12 inches then up to 1.625".
Not so much to be cool but to gain space.
It looks like you got it covered though

E
Who is waiting for more good work as usual!!
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Old 12-16-2015, 08:26 PM
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Yeah, I thought about that, but one of the co-conspirators on this project thought 1-5/8" was the way to go...and he's got a lot of experience racing one of these things, so I respect his opinion. I also looked at tighter radius bends (a 1-5/8" CLR is available at twice the cost) but it wouldn't gain that much space where the interference is. So far it's coming out nice, just a lot of work. I want to hear it run, I understand they sound pretty evil at full tilt!
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Old 12-16-2015, 10:40 PM
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30 years ago there was a Ford 4.9L six that I played with, Dual 390 Holleys and 6-into-2 header sparked by a Mallory Dual Point, I think the Camshaft was Isky.
There is just something about an "inline" engine 4, 6, 8 that when running between the Peak Torque and Peak Horse Power will raise the hair on the back your neck...


Then again there aint nothing like the sound of a Big Block in the morning

E
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Old 12-17-2015, 12:43 AM
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JaysinSpaceman JaysinSpaceman is offline
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I had a 63 Chevy pickup with a 292 I-6 and it definitely rates as one of my favorite engines, big block torque, not a whole lot of HP though. It and the 250 I-6 in a 70 Chevy pickup I had were the two smoothest engines I have ever had. You could set a glass of water on the valve cover of the 250 and it would hardly make ripples in it. I have always wanted to build a light weight hot rod around a I-6, I have even toyed with the Idea of using a Jag Overhead Cam I-6 in a hot rod just because they were beautiful engines.

Nice start on the header. I think you have enough space between the header and intake that it wont heat-soak too bad. You might try stainless heat shields just for something different, it'd look cool if done right on an exposed engine.

Thanx for posting the progress.
Jaysin
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Old 12-17-2015, 08:22 AM
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I had an F-150 with a 300 six in it for my first vehicle. I liked that truck a lot, but there was no budget for hot rodding it at the time. Just good basic transportation...I think the only option was the FM radio.

I like the inlines. I currently own a Chevy Trailblazer with GM's 4.2L inline six. I don't have anything bad to say about it.

How would you do heat shielding? Attach to the intake manifold? It's definitely an option. I'm not sure how exposed this is going to be. There may or may not be hood sides on it. I'll be sure to post pictures...I should have taken one or two last weekend when I dropped of the beginning of the pipes.

Last edited by Graham08; 12-17-2015 at 08:24 AM.
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Old 12-17-2015, 12:23 PM
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I use 10-24 (Coupling Nuts) welded to the header tube.
You can cut the nuts off to the length you need.
I then use thin aluminum sheet (1/16 or less) and I form it to the required shape.
I try to put the sheet spaced away from the heat source a minimum of 1/2" or about the full length of the nut.
For the fastener; I prefer studs (All Thread) so the assembly is, the stud in the nut, then a washer, then the shield, then a washer, then a nut. You can get mechanical lock nuts if vibration becomes a problem. I have also used Stainless Bellview(sp?) washers. I also will try to loacte the mounting points near the edge of the Shield and I fold the sheet back over itself (under 4 lookz) to give a double thickness at the mounting point, particular when I'm using sub 18-Ga.

Locate the attachment points with maintenance in mind. & where there isn't room for the above I have simply formed tabs that rest against the e-tube and attach with a Hose clamp holding the shield off the tube as much as possible, takes a little more forming and I do try to use more to the 1/16-thk material in this case.

Aluminum sheeting like this will not do much in a 'long' hot soak (Idling) situation but is dramatically effective in running conditions.
If you know that you are going to have issues you can shape the heat shields to catch the cooling fan wash.

Note: You do this, you have to keep it clean, pack it full of mud and it will not work!

There was one Turbo/Dn-pipe that had no place to go but, real close to the Fiberglass Firewall and we could not, after a week, find a better place so I built this same structure out of 5 sheets of metal.
the outer/visible one being Polished Stainless then 4 sheets of 18 Ga Alm, black anodized, SS Acorn nuts, and all that nifty stuff. It looked good and more importantly it worked! The paint stayed on the glass firewall!

E
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Old 12-17-2015, 01:22 PM
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You're my hero. Is your boy helping you out with these?
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Old 12-17-2015, 01:40 PM
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Quote:
Originally Posted by entropy View Post
I use 10-24 (Coupling Nuts) welded to the header tube. <snip>
Thanks for the advice! I wasn't sure if attaching to the header was OK because it would heat the shield faster through conduction. We may head down this path at some point. George (the guy who used to race a 292 powered car) thinks the gap should be OK based on his experience. We shall see...



Quote:
Originally Posted by TheBandit View Post
You're my hero. Is your boy helping you out with these?
You are way too kind. We're not quite to metalworking yet (he turned four yesterday), but we're deep into Legos. He got a bunch for his birthday, so we have been spending quality time building stuff.
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Old 12-18-2015, 12:54 AM
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We are brick builders in our house too. Right now we're doing one of their advent calendars where he opens a mini set or figure each day leading to Christmas. The last year has been incredible watching him advance from hardly being able to follow the instructions to now building complex contraptions of his own. I want to get some of the motorized and programmable stuff so we can completely geek out. Do you guys watch EvanTube? Lego Movie fans?
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Old 12-18-2015, 07:27 AM
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Cool! We have DVR'd a few of the Lego movies, and Grady is pretty into them. We just got him into the smaller Legos this summer...after coming home from the store with his first set, he spent about three hours straight building stuff. He's getting pretty good at following the directions to build them as pictured, but also does well at coming up with his own creations. I'm happy he is really into them...so much better than TV and video games!

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Old 05-25-2016, 10:01 AM
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I got back to this project over the past couple weeks.

Here's the "victim":



It's pretty cool...a '38 Chevy steel body mated with an older dirt late model chassis. The body was really rough, but it looks pretty good in this form. Dave's intention is to have a tribute to days gone by without specifically replicating any one car. Plan is to run it at vintage nights at some of our local tracks.

Pipe #1 was the real challenge, getting it to fit around the power steering pump and the alternator. It also caused #2 and #3 to get interesting because it limited the amount of space available to get them all pretty close to equal length.



#2:



And #3:



On the table for final welding:



This was right before I cut the tacks holding #2 and #3 into the flange so I could weld all the seams all the way around. I did my normal treatment of the flanges, welding the pipe on the inside and brazing with silicon bronze on the outside.

Got the rear set tacked together last night:



After taking a step back...the rear set needs the turn-out added yet. I have to pull these off and finish welding everything. The primaries all came out between 35" and 36", so I was happy with that.



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Old 05-25-2016, 01:56 PM
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Awesome as usual. What kind of design work went into selecting primary dia/length and collector dia/length?
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Old 05-25-2016, 03:35 PM
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Thanks!

There wasn't a ton of science behind this because it's ultimately not going to get run that hard. George suggested 1-5/8" primaries, 36" long, and 2-1/2" collectors. Unfortunately, the only budget-friendly collectors I could find in a 3-1 (Hooker) were for 1-1/2" primaries, so I had to step down from my transition pieces in the flange.

Given a larger budget, I would have gotten collectors from Cone Engineering because they have a number of options for 3-1's.

I was somewhat concerned about getting the primary lengths close just to make sure it runs well. If I did this the easy way, they would have easily been 6+ inches different in length, and I wasn't comfortable putting my name on that.
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Old 06-06-2016, 09:29 AM
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Forgot to wrap this one up...it's been a whirlwind couple of weeks!

Side pipes and turn outs. Should be able to hear it good!



That's also a good shot of the left nerf bar. Nerf bars were one of those, "While you're at it..." kind of deals. They came out nice, though.

A closeup of the hanger setup to keep them from cracking. The engine is rigidly mounted, so it made the exhaust hanger pretty simple, just split some of the same 2-1/2" tube the side pipes are made out of and used some 3/4" tube and hose clamps:



Yeah, I like my lift alright!



Tried out my "new" drill for my notcher on this project. This was my Grandpa's...my aunt gave it to me a couple weeks ago. I did a little checking, and the company that made it was bought out by Black & Decker in the early '50's. It only turns like 350 RPM, so about the perfect speed for this application.



I left a 3/4" version sitting at a garage sale a few years ago. I probably could have owned it for $5 or $10, but I knew I would only end up injuring myself with it...

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