Looking for your opinion So I'm a mechanic i replace my head gasket on my 1996 ford ranger 2.3 gasket the head bolts the hole 9 yards

I torqued the head 51 to 90 ft pounds and the sequence was 51 to 60 to 80 90 so I don't know if i should re torque head bolts or leave it? I'm afraid if i torque them again one will break what do you think paul?

Doing it that way you did is just inviting another head gasket failure.

Undo the bolts, in the correct sequence, and if the bolts are reusable then re-torque them in the correct sequence and stages. The staging evens out the load applied to the head during tightening. Most modern alloy heads/blocks use stretch-bolts which Can't be re-used. Check for yourself, I live in a country where the Ford Ranger is rarely seen so have never yet worked on one. If they're not stretch bolts then as long as they are clean and degreased, then use them, and observe whether Ford specify that torquing is to be done with the bolts oiled or dry; different manufacturers on different engines will specify oiled or dry (as an example, all current Volkswagen Audi Group engines specify dry bolts, all current Subaru models specify oiled).

Personally, given the expense of another HGF, I'd go further and actually remove the head again to check that it has not already been distorted by your mistake. There's definitely a fairly high chance that when you apply an engineering straight-edge and feeler gauges to the head that you will find a slight distortion. If it's only a couple of thousandths of an inch across the longest diagonal measurements then you might decide it's worth chancing it, hoping that the re-torquing will twist the head flatter again and any minor remaining distortion will be taken up by the compliance of the gasket, but if you are going to risk that then also fit another new gasket as yours will already have been crushed flat removing its ability to compensate for very slight distortion.

Again, if it was me, and I found any distortion at all, I'd re-skim the head flat if I'd already invested the time and effort to remove and measure the head, and possibly have paid for a new set of head bolts. If it's been skimmed a few times already then you may also need to add a shim to the gasket to avoid raising the compression ratio and to totally remove the chance of valves hitting pistons if yours is an interference motor like on most modern engine designs.

I think you need to check this with someone who knows the answer for sure rather than random people on the internet who may give you the wrong or right info. I also think that if you are a mechanic then you would really know this.