Will a 400 small block fit in my 95 S-10 pick-up?

Yes. The smallblock into S10 swap is pretty popular, and a 400 isn't any larger on the outside than a 350. I'd strongly consider upgrading the rear axle and transmission too.

A small block 400 is physically the same size as a 350. Several companies make headers and engine mounts to make this swap almost a bolt in. A V-8 S10 is fairly common because it is a pretty simple project with fun results. Back it up with a good, strong tranny and a rear end that can take the abuse, and hours of fun and enjoyment will be had. Check out Summit Racing or Jeg's for some parts and pieces to help out. There might be one kit with all the parts you need in it.

Yes it'll fit and be a blast for you. The 4.3 engine is basically a 350 engine with the front two cylenders cutoff. The bellhousing patterns are the same. The best things to do are run electric cooling fans get a bigger radiator and a set of shorty headers. All of these can be purchased through Jegs or Summit, and possibly Advanced Adaptors. If your going to put fuel injection back on it Edlebrock, and Holley make stand alone fuel injection systems that will work well. Or get the system from a junkyard and buy a wiring harness from Howellinjection.com and put it together yourself. At any rate have fun with it and let us know how it works out.

A 400 small block will fit in a golf cart if you are determined and smart enough.

Yes,all the small blocks are the same size.Pretty easy job.

Physically -- Yes.

But there will be a great deal of modification necessary.

I think if you go to POWERBLOCK.COM, there was an episode featuring this very conversion.

Good Luck

OF COURSE IT WILL BUT YOU WILL HAVE TO DO SO MODERATE TO HEAVY MODIFICATIONS TO IT BUT THERE ARE TONS OF PEOPLE WHO MAKE A SWAP KIT FOR IT ASSUMING YOU HAVE A 4.3 V6 IN IT NOW BUT IT SHOULD BE NOT TO MUCH OF A PROBLEM DEPENDING ON HOW DEEP YOUR WALLET IS

yes it will you will have to move motor mounts and maybe cut firewall