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Re: new engines for the GMCs [message #316482 is a reply to message #316311] Sun, 23 April 2017 09:29 Go to previous messageGo to previous message
Mike S   United States
Messages: 82
Registered: February 2017
Location: Vero Beach, FL
Karma:
Member
First, This isn't about mileage or even cost. Anything that goes round and round will wear out.
My GMC burns about 1 quart of oil every 500 miles, and I am OK with that vs. the cost of a rebuild.

Second, the last 455 casting was done sometime in the 70's. When I helped out at my buddies engine shop, about 50% of the engines that came in for a simple rebuild, took some kind of major component. That's why the top shops are quoting $7500 for a rebuild. It is not customer friendly to say $5000 and to then come back and say you need another $1500 because your block won't take a rebuild. The rarer the more money.

Third. The LS would be a perfect motor, if it would bolt up with just an adaptor(that are out there cheap), a custom oil pan and front mount(easily fabricated). You could sell those parts for around $500 and be OK making them. So a $500 kit, $2500 late model low mileage junk yard engine,$400 wire harness and $300 computer tune and your running.

I will make a kit to bolt up the LS to the 425 transmission. But It needs custom front mount, rear mount, oil pan, trans pan, and an adaptor between the differenial and the trans. I am looking at $1800 to $2000 for those parts. And to fit our coaches, you are going to have to add 3 inches to the height of the step near the transmission to make it work. And it is getting real close to the hatch. it may even need to be raised a little to clear the truck intake.

So what are the other choices?

To me there are 2 that make sense.

First the more expensive. World Product sells and engine called the LS hybrid. It is small block Chevy based bottom end, set up to take LS cylinder heads. Again, it is not cheap. The first quotes on the short block exceed $5500! With a fresh set of heads and all the other component, It will probably be near $10,000 for complete engine ready to drop in. But you will get easily 450 HP and 500 torque.

As always speed costs.

The other option is GM sells a motor they call HT383. Google it. It has almost the exact horsepower and torque of our stock 455s. The front mount and pan prototypes will be done soon. you will have to raise the hatch, and I will let everyone know how much soon. Jegs has the motor for $4500. It has a 2 year 50,000 mile warrantee. Add a Fitech fuel injection and you would have a great motor for our coaches. Keep in mind all your front accessories need to be changed. But GM does sell a kit with everything you need, brand new, for about $1000.

How much is brand new worth vs. 40 year old everything!

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