Help, wrong year for you guys but need help

[Sharps-Nut]

I started changing out the cab and all sheet metal on my badly rusted out 1974 highboy. I am putting a nice nearly rust free 1978 cab and bed on it. The 74 highboy has the tank behind the seat, the 78 is in the bed side. If I take the truck to work I could have the filler neck hole plasma cut thru. Will this ruin the paint as its original and presentable. Is there a better way of doing this. I have tried to do the job right with complete wiring harness change so there is no butt connectors and I don't want to muff up this whole tank hole thing. I would like to post some pics of the before during and after. This site is an almost daily read for me, truly great site with tons of tech stuff. Thanks for the help. Sharps-Nut

[SmokeyBear]

Use a hole saw or a drill and a jigsaw. A plasma cutter will bubble the paint about half an inch outside of the cut line.

[qman]

Put tape over where you'll cut. this will minimize chipping paint.

[ford71]

a rotozip will work well for thin body parts.

[bluef250]

Might consider putting tank in back and installing fuel fill in the bed and avoid both issues of having tank behind the seat and cutting the exterior sheet metal on bed. Once installed a bed treatment would cover body work.

http://www.fordification.com/fuel-tank02.htm

[stockr]

how about using the drill bits that they use to make the holes for the door knobs...im sure there is got to be one for metal... and GMAN is right about the tape...what ever you decide to do...put a couple of layers of tape just to be on the safe side...

[hardtailjohn]

First thing to remember is that you're not going to be cutting a prefectly round hole.. the tube goes through at an angle other than 90 degrees, so the hole isn't going to be perfectly round when it fits right. When I have to cut a hole like that in an airplane, I drill a few smaller holes, like 3/4" around the inside perimeter of the hole to be, then use a sheet metal nibbler...about $10 at Radio Shack (NOT shears..they distort the metal).... to do the cut, then take a file and knock down the sharp edge and finish with a bit of sandpaper. You should have a nice looking job, and it wont take long, and best of all, wont destroy the paint. Hole saws are known to jump and rarely cut a good hole... the plasma will burn the paint, and a jigsaw will make a huge mess, not to mention distorting the heck out of the metal! Past experience has shown me why I don't do those things anymore...
JH

[Sharps-Nut]

Thank you for all of the help. I prefit the tank last night and marked the floor for hold down clamps. Tonight I am going to make a temp using the old cab for a pattern. I am armed with some good advice now and know the plasma is a no go. Holes and end nippers sound like its within my skill level and within my tool arsonal. Any opinion of spray on bed liner for a floor covering thru out the cab to keep it rest free and easy to hose out? Thanks for all the help. Steve