[rich weyand]

Why replace the side tanks? You are much more likely to get rear-ended than t-boned. One third of all serious auto accidents are rear-enders. Replacing the side saddle tanks with a gas tank that is between the frame rails but behind the rear axle will not appreciably improve safety and may make it worse. Modern cars are so low in the front, the rear-ender is going to go right under the bumper and split the tank, especially on a 4WD K truck that rides so much higher.

Also, it is easier to avoid a T-bone than a rear-ender. The rear-ender is completely up to the guy behind you. Nothing you can do about it.

If you put the new tank between the frame rails AND in front of the rear axle, that's different. That is the current standard.

But don't forget, GM made almost 10 million C/K trucks with saddle tanks. The biggest numbers of deaths to date from post-collision fuel-fed fires I have seen is about 200. That is, deaths caused by the fire where the person was not already dead from the impact. Just figuring 100,000 miles per truck, that is about a TRILLION miles traveled, over forty years, netting about 200 deaths from side-saddle tank fires, or about 5 per year across the entire United States. And the rate in trucks without saddle tanks is not zero, but about half the rate with saddle tanks.

You are about 12 times more likely to get struck and killed by lightning in the United States as you are to die in a C/K saddle tank fire.

Now, if you (or your son) are one of the five people to be killed in a saddle tank fire in a given year, that really sucks. No question. But it's a very small number of deaths in a country where 32,000+ people die in auto accidents every year. One-third of those are alcohol-related. Texting while driving is also a growing problem. And in the Indiana papers, lots of vehicle collision deaths are people killed when they are thrown from the vehicle for not wearing seat belts, where other people in the same vehicle wearing seat belts walked away without any injury at all.

So, if you want your son to be safe from death by auto accident, don't worry about the C/K saddle tanks, and don't replace them with a tank behind the rear axle. Instead, concentrate on these:

1) Have your son be home before the bars close. A large number of DUI crashes occur within the first hour after the bars close. That's when the cops here are all out on patrol for DUIs, because that's when the accidents happen.

2) Make sure he wears his seat belt. A ticket for no seat belt should result in suspension of his driving privileges by you for a couple months. Make sure he knows that. Same for all of his passengers.

3) Make sure he isn't drinking and driving. Make him a deal that if he has ever drunk at a party or something, even underage, you don't approve BUT he compounds the error TEN-FOLD by driving. No matter the time of day or night, he should be able to call you and you will come and drive him home. But if he gets a DUI, that's it. No driving privileges for a year, or you will take the truck away, or something else draconian.

4) And no texting while driving. You can fix most AT&T smartphones (and maybe all smartphones now) so they will not send or receive voice or text when their internal GPS determines that they are moving at vehicle speeds (i.e. not walking). This app is password locked, so once you set it he can't turn it off. It's called "Drive Mode".

Finally, one lesson to pass on to your son he won't hear in Driver's Ed. The most dangerous maneuvers in a vehicle involve turning the steering wheel to the left:
1) making a left turn across oncoming traffic.
2) making a left turn into a cross through street, crossing the right-bound traffic.
3) pulling into the left lane to pass on a two-lane road.
These have the highest closing speeds. Remember: Two wrongs don't make a right, but three rights make a left. I avoid left turns when I can.

Having said all that, the one serious accident my son had was making a left onto a through cross street (do they ever listen?), and getting T-boned at 50 MPH in the left front fender. Everything left of center and north of the firewall was gone. Would have been well in front of the saddle tank, but still makes you pause.

How about a fuel cell? That kills the possibility of a fuel-fed fire no matter where you put it. You can get them with the 0-90 ohm sender unit included, so no wiring or gauge changes. Just bolt it down in the center of the bed behind the cab, well inside of the frame rails and ahead of the rear axle.