How much would it cost to rebuild a 454 on a 1985 28' Regal? Would it be smarter to just put a new engine in it? And, if that's so, how much would that be? I can't/won't be doing any of the work myself and it has to be a turnkey job with some kind of a warranty.

I would think you would be talking about in the 4-6k range to have yours rebuild Jim and a crate reman 454 would probably be about the same. Nice thing about a crate you can choose where it is coming from then also what kind of warranty you are comfortable with (i.e. a Jasper or a Chevy reman). Rebuilding yours would be a local warranty most likely. Of course you may want to upgrade to a HO 454 while your at it.

Based on my experience, I would not go with the HO. They make great power at the top end, but there will be a flat spot between 2nd and 3rd gear until you get up on the cam.

My stock cam gives more power at lower rpm than the HO and gives better mileage. (Not nearly as much at the top end though)

GMs warranty is limited to parts, limited labor and only if installed by licensed tech. Technically the 454HO is only approved for pre 1979 non emission applications, it may not cover the coach installation. Check carefully.

Then there is quality…not. The front seal was installed crooked, leaked when brand new. Also one valve spring was broken. I had to do a valve job at 15,000 miles… 3 intake valves burned.

My 454HO was unreliable. I would go with a reputable builder and their warranty.

Jim, this is a marine engine but probably set for torque, they will be a bit pricier since they may have gaskets to prevent saltwater corrosion. http://www.1800runsnew.com/new-base-engines/
It has been a while since I looked into this but at that time Jasper engines were not holding up in my area. Fwiw

Another option is a used engine with a nationwide warranty from LKQ. We have installed a number of different used engines with low miles in less than a day and with a one year warranty. There are a million 454's from every P-30 series truck available and you can get them for less than $1,000 delivered to your mechanic. It requires you to transfer your existing equipment and in newer ones you can get the computer and fuel injection. What you get is a tested completed engine that has a good history, good compression and all cleaned up. Check them out.

Hi Jim.
You know I just finished getting my 454 rebuilt.
Mine was bored, oversize pistons, RV cam, Heads rebuilt for $2000.
I had my engine rebuilt because of its low mileage and its a "roller" motor.
The engine builder also came to my house after I had it installed and primed (oil) the motor and set the the timing with his laptop. I was very pleased.

I've built many sprint car engines. I learned the hard (expensive) way how I'm happy to do it now. From my experience, I would suggest that you have the engine re & re by a shop you trust for good work and have them send it for rebuilding to a proper engine machine shop where all they do is rebuild engines. Tell them to rebuild, not re-furbish the engine. They will rebuild it as close to new as possible. Some garages will only replace what is worn. Tell the engine shop what it is for and they can probably suggest some improvements, based on their knowledge and experience. Best value for your money. A shop that also builds race car engines would be my first choice. Ask around at parts stores, the guys who will pull the engine, etc. Then talk to the various shops and get estimates. See what you'll get for your money. In general, a standard Chevy rebuild isn't a problem.