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  #16 (permalink)  
Old 09-10-2013, 01:31 PM
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Had this same scenario on a car I built, and I did what Ogre initially mentioned. I used a parting wheel to separate the collector just below the factory weld. Then I cut enough off one side to allow the collector to til inward, and welded it back on. Tack it in place while they're bolted to the engine, and it will hold it so you can remove them to do the finish weld.
As for headers leaking, I stopped using all the useless header gaskets that are "high performance". I went back to using factory metal laminated stock type gaskets, and all my leaks have ended. Used to change the gaskets about every 6 months to a year, and now I never change them.

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  #17 (permalink)  
Old 09-10-2013, 03:03 PM
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Quote:
Originally Posted by ogre View Post
ramjet350 w/ mefi4 controller, gm crate motor. maybe i need better gaskets.
napa has the same part number for all sbc manifold/headers
going to put a new ss exhaust sytem on the truk next spring,
still thinking the ramhorns will work better
those engines are notorious for incorrect fuel curve
and a over rich idle. I be the timing curve especially at idle is WAY OFF what the engine really wants. Retarded timing equals over heated exhaut and gasket issues every time.
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Old 09-10-2013, 03:06 PM
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Originally Posted by cal1320 View Post
Ogre, I always file the flanges of any header before I install it. Even cheap headers will seal and not have gasket blow out problems if you do this.
i do the same thing black paint to see low spots adn a big bodymans
metal file across the flange., then a DA with 80 paper.
paint file some more. gaskets last forever.
The header bolts always need retightening on a new install. then they
take a set and stay tight.
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  #19 (permalink)  
Old 09-10-2013, 04:50 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
those engines are notorious for incorrect fuel curve
and a over rich idle. I be the timing curve especially at idle is WAY OFF what the engine really wants. Retarded timing equals over heated exhaut and gasket issues every time.
Was just going to mention this.

Here is a stock Ramjet 350 on the MEFI and then a Ramjet 350 with with an 0411 PCM with an optimized calibration.

212rwhp/265rwtq


311rwhp/334rwtq


Avoid the 2" outlet Ramshorns, go with the 2 1/2" aftermarket units as "real" 2 1/2" Vette units can be pricey.

I'd still do a decent header over any rams horn though. IMO

peace
Hog
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  #20 (permalink)  
Old 09-10-2013, 05:40 PM
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The MEFI controller was actually for boat engines.Idle & cruise are always way rich.The 0411 is a big improvement.
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  #21 (permalink)  
Old 09-10-2013, 07:18 PM
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mefi = marine efi controller and it gets 20 mpg at 80 mph. i'll leave it rich
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  #22 (permalink)  
Old 09-13-2013, 10:17 AM
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Originally Posted by ogre View Post
mefi = marine efi controller and it gets 20 mpg at 80 mph. i'll leave it rich
Are you running the O2 sensor that some Ramjet s come with? That helps with the closed loop fueling lots. The power tuning can use some work though.

peace
hog
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  #23 (permalink)  
Old 10-09-2013, 10:11 AM
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This is just a suggestion,,and I understand your dilema,,but If it were me,I would measure how much of the header needed to fit,,and simply C-notch the frame,,it looks like you're only looking at a 1/2 an inch or 3/4 at both the upper and lower portion of the frame and then,,cut some support pieces and weld them to the frame,,you're removing so little metal that there is no way you're compremising the integrity of the frame.This way,,you could use the headers you have without touching them.Then,,you can work on the sealing problem without wondering if you cut the headers wrong,,Just an opinion,,like I said,,that's what I would do,I've actually had to do this several times doing engine swaps in s-10's,,Jeeps,,and other vehicles,,I've always had a thing about putting the headers inside the frame.
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  #24 (permalink)  
Old 10-09-2013, 02:00 PM
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Quote:
Originally Posted by 1971BB427 View Post
Had this same scenario on a car I built, and I did what Ogre initially mentioned. I used a parting wheel to separate the collector just below the factory weld. Then I cut enough off one side to allow the collector to til inward, and welded it back on. Tack it in place while they're bolted to the engine, and it will hold it so you can remove them to do the finish weld.
As for headers leaking, I stopped using all the useless header gaskets that are "high performance". I went back to using factory metal laminated stock type gaskets, and all my leaks have ended. Used to change the gaskets about every 6 months to a year, and now I never change them.
X2 on the factory metal laminated stock type gaskets.
But the flange MUST be straight. I've had flanges that I've had to fill low spots with weld, then grind and belt sand to get 'straight' - thin flanges.
Once flat, mostly and gasket seal up ok - providing tune is right as F' bird says.
My tick still goes with the metal gaskets though

Surely you can just heat and bend those pipes a bit...


Duke
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Old 10-10-2013, 04:19 PM
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header clearance

I'd either move mtr over or cut out clearance on the frame sidewall, then weld up a new sidewall with 1/8th thick sheet metal to fit the cut out.
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Old 10-10-2013, 04:37 PM
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I want to 'plug' a great gasket. REMFLEX. i used an alum. 4 bbl intake on my 250 chev truck, along with steel hedman headers. they leaked loud. seems the header flange was 1/8 in thick, and the intake was 3/16 thick. too much gap. remflex is made of a flexible graphite material, which expands with heat. the noise went away! lol. a bit pricey, at 50 bucks, but a real lifesaver. --steve
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  #27 (permalink)  
Old 10-10-2013, 07:46 PM
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Milling machine ?

We have angle milled the flanges on cast iron manifolds to give a wee bit more tilt. "You would have to cut slower on headers
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  #28 (permalink)  
Old 10-11-2013, 08:33 PM
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I'd do rams horns, or even better extrude hone rams horns. Maybe a set of sanderson headers would work... aren't they the ones with the high-flow cast iron headers that fit like a manifold?
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  #29 (permalink)  
Old 10-13-2013, 12:46 PM
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There are a lot of good ideas on this subject. I would agree with F-bird though on modifying the right hand side of your subframe splice. Which has been done nicely by the looks of the pictures.
I have ran into the same issue on that vintage of 50's chevy pick up. I split a piece of 5 inch outside diameter 3/16 wall thickness tubing about 3/8 ths of a pie section of it. Then notched the frame to fit the splice tubing into place. I gave myself enough clearance for the flange and torque flex movement of the engine and header under load. There was never a problem with with any weakness or cracking at the splice. Wish I had pictures of the work but it was many years ago.
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