I am not familiar with the web site you listed so cannot help you there. However, I have personal exprience with Jasper Engines. I bought a remanufactured long block 350 from them and installed it in my truck in August, 1997. Still running and performing very well. Cost of the engine after returning the core was almost 1,800. Jasper was really easy to work with (I did it all by phone). You could contact Jasper for pricing, service, etc. as a second option. It's always good to have options and when a satisfied customer is willing to recommend a company, that's worth a lot, in my opinion.
Jasper does make good replacment engines. I'll give them that and they have their own sponsered cars so they run what they build.
Big isue with a lot of places is, you can get a moderatly decent engine, in some cases, but its not dialed in correctly it is just a running engine. I would not suggest that you purchase from a company called SRS engine remanufacturers. They suck and so do the Junk Yard engines they sell.
If the engine is dialed in properly then you get all the HP that can produce out of the Box no playing. Jasper does this. GMPP doesn't. You get a good crate motor from GMPP but you still need to spend some time with it in order to get the full potential of that engine. It is good out of the Box but it could be much better. Jim Pace sells some good Crate engines still not really dialed in well.
So be ready and willing to play with the cam and other stuff when you get a Crate motor so you will get the best performance and economy that engine can give up.
And ..... Go with a 350 not a 305. They look a lot alike so id you decorate it up just right the Smog Nazies will not know the difference. The new castings have the Dip Stick on the same side as the 305. Buck for Buck more will be produced with the little larger displacement engine. (5.0 vs. 5.7L) Better power will give better gas miliage up to a point.
I like the 305 but for a work engine only on a pickup. They take a lot and are pretty robust but don't produce very well as far as usable HP and Torque. I have a 305 in a 93 with 180,000.00 on the odometer and it is still going strong. It has no get up and go like the 5.7L SBC but it is fine for a work truck.
Shop around , don't get sucked by a good warranty. There's some good engine builders out there so ask questions and even try to get some feedback from other customers. 305 or 350, it's a pretty good sized investment. Check out my problems in the ignition upgrade forum. Finally got everything going allright but it was a pain in the ass. At the time I bought mine it was about 70% for, 30% against this certain company. Now it's visa versa. They had a 7/70 warranty too. Had to yank motor out twice, no labor reinburnsment like promised ( didn't read the fine print) Ran about $1900, around 500 was just flushed. Good luck in your decision and happy cruisen
I prefer to build/assemble my own engines, this way I know exactly what they are. I use a reputable shop for all the machine shop work. When building a high performance motor, if you buy a remanufactured or crate motor, I think you wind up buying parts that you won't be using but you paid for. There are a lot of suppliers that will sell you a tailored kit (pistons, crank, and rods) and you just need to assemble everything. You can buy heads already assembled (the sky is the limit here). No there is no warranty...but then again there's always the fine print in a lot of those warranties when you buy a remanufactured or crate motor. I use 350 4 bolt main blocks pulled from GM trucks. Just finished one recently for my sons beastly looking 3/4 ton pickup truck...the cost was around $1800. It has new forged pistons .030 over 10:1 comp ratio, reground forged crank, stock remanufactured GM forged rods and stock cast iron big valved heads with roller tipped rockers and a mild cam. We may upgrade to Edelbrock Performer heads later, but then again this is a truck that my son uses daily for work (roofing) and it was designed to haul heavy loads not race. Your not going to get a remanufactured/crate motor like that for $1800. This motor is capable of withstanding a nitrous system and/or TPI injection, if/when we decide to pull the motor and use it in another project later (GTA Trans AM in the garage). I realize not everyone has the knowledge or experience to build their own motor, but neither did I when I first started out. A lot of my knowledge was gained from reading, reading and more reading and then doing. For those who choose to buy remanufactured engines, I have heard that Jasper engines are a good choice for the money.