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Old 05-27-2006, 12:06 AM   #1
my 85 gmc
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header question?

My question is I have a set Flowtech headers, which I've had for the past two years and I'am considering putting these on my 1985 305 but i'am concerned about quality? Also if I use these header which gaskets should I use and which port size round or square?

Rgds Rob
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Old 05-27-2006, 12:45 AM   #2
Chevrolet4x4s
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Re: header question?

Quality to my knowledge is pretty good ask Summit or your local parts store about the gaskets or mabe someone on here has more knowledge on this subject than me.If you do put them on would you please post the gas mileage increase as I am thinking about putting headers on my truck.
thanks
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Last edited by Chevrolet4x4s; 05-27-2006 at 12:45 AM.
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Old 05-27-2006, 10:22 PM   #3
my 85 gmc
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Re: header question?

Another question along with the quality of the Flowtech headers are there any tips or tricks to installing headers you guys can pass along? Also which plug wires do you suggest I've had good luck with Taylor wires in the past.

Rgds Rob
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Old 05-28-2006, 12:09 PM   #4
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Re: header question?

Most header installs can be painful, but there are things that can be done to simplify the install on a mid eighties truck. The driver's side goes in from the bottom and the passenger goes in from the top, if I remember right. Of ocurse it depends on which age of a motor you may have as to where the oil dopstick is on the motor (left side or right side). The gaskets that I use are the "FELPRO" composite material and I coat them on both sides with "COPPER COAT" gasket sealer and let it dry. As I bolt the headers in I put TEFLON TAPE on the header bolts (for two reasons) to keep the header bolts from backing out and to make the threads stay clean. I haven't head a header leak or a bolt back out in years on three or four different vehicles (I have headers on all of my vehicles and my son's truck also). The front bolt on the driver's side is not the regular header bolt, since there is a bracket there for the power steering and the A/C unit on my trucks. I took the bracket and trimmed it down to clean it up and got rid of the part that goes to the top of the A/C unit. I used the factory bolt and added spacers as necessary to get everything to line up to the power steering unit.

The taylor wires or a good set of MSD wires work real well with headers.
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Old 05-28-2006, 05:22 PM   #5
my 85 gmc
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Re: header question?

Thanks for the install advice "piecesparts" it is useful advice but I'am still leary of the quality of these Flowtech headers but they are new and still in the box. Which gaskets should you use square or round ports? Thanks Rob
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Old 05-28-2006, 05:54 PM   #6
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Re: header question?

I am not sure what the Flowtech headers have for ports, but the round gaskets work for about everything that I have installed. I usually hang my headers with a long bolt on the front hole, and another long bolt on the very back hole. That will align the header, then I drop in the exhaust gasket, s ince they are slotted on the very end holes. I then start the rest of the bolts inside the header flanges. There will most probably be some that are going to be close to the header tubes and will be required to be installed FIRST and then snugged up FIRST, just so they will be able to be put in t eh flange and tightened without binding. I also have made a couple of header wrenches for my stuff, one with a bent open end to allow for more access to the bolts and another with the box end shaved down to allow for tight clearances. It is amazing what a grinder and an acetylene torch can do.
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Old 05-28-2006, 11:15 PM   #7
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Re: header question?

As far as quality, the flange thickness on Flowtech's is 5/16". Alot of header brands come with this thickness size. Your higher quality headers, like Thorley's Tri-Y headers, use a 3/8" flange. They say it keeps the flange from warping. But some Hedman headers use a 1/4" flange and others use a 5/16", so your Flowtech's seem to be in the middle ground as far as headers go.
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