So if it cost you a few thousand to convert and you picked up a few more MPGs, then payback would only be five years or so. That also assumes that you don't use the new found power and putter along like the old motor would have performed.
If your present motor is trashed, them maybe the conversion is justified. I jush hope you can do all the labor yourself because paying someone to do it will be expensive.
Les Stallings
South of Nashville, TN
2002 Monaco Dynasty Jack 38, ISL 400, TAG
Toad: 2003 Saturn LW300
A complete Vortec big block is not an easy drop-in, because of the electronics, if that is what you are talking about. Nor is it feasible to "convert" your existing 454 to a Vortec (7400 or 8100) for the same reason, too many expensive new parts, both inside and outside the engine.
However, you can get the basic Vortec mechanicals (including the improved flow heads) by building on a GM Performance Products crate engine like the HT 502. The HT 502 will build to match the performance of the 8100 Vortec, with the right carb and intake manifold.
If your existing 454 has a sound short block, you could rebuild it with performance parts, as a carb engine or aftermarket TBI engine, for probably a lot less than a new crate engine. 290-320 HP around 4500 rpm, and 400-450 lb-ft through low to middle RPMs is a pretty common 454 build for towing and RV use.
I don't know. I think I'd change out the chassis, too. And the body, as well.
States I have spent the night in my current rig, bought three years ago.
Have RV'ed through 49 states and been in all 50, just short of my half-century.
I've got the HT 502 in mine and it rocks !! I am getting about 6-8 mpg. I'm sure it could do better if I could keep my foot out of it. The engine is a direct bolt-in, except for the lack of a mechanical fuel pump mounting boss. Low end torque is great in this motor - 500ft/lbs just off idle.
While you've got your motor out it's a good time to service/replace everything you can think of.
1990 Pace Arrow
502 GM Crate Motor
Gear Vendors
Stan's Headers, 3" mandrel bent exhaust and Magnaflows
vosks wrote: I've got the HT 502 in mine and it rocks !! I am getting about 6-8 mpg. I'm sure it could do better if I could keep my foot out of it. The engine is a direct bolt-in, except for the lack of a mechanical fuel pump mounting boss. Low end torque is great in this motor - 500ft/lbs just off idle.
While you've got your motor out it's a good time to service/replace everything you can think of.
You have several things to think about. First, yes it is worth it, primarily for mileage increase. The deal is that the 8.1 has FAST BURN heads. This means it can run higher compression and not detonate. There is an optimum point in the stroke for the fire to occur to deliver the most torque to the crank. Since the burn time is shorter, less burn is wasted during the less efficient part of the stroke. Fuel injection is only a small part of the efficiency equation.
I put in a 502 HT with multiport FI, but it has older design cast iron heads, so I'm not getting the full advantage of newer technology. My gas tank leaks when full, so I don't have an absolute on mileage, but I've guessing about 2 mpg increase just with FI.
As far as what is involved, I can give you some guidelines, but I installed a gen VI block, where as the 8.1 is a gen VII block, but they are very similar. You can use your old engine mounts, but they will need to be modified with a grinder. The exhuast manifolds are the same. One thing that is very different is all the accessories run on a serpentine belt, rather than the multiple belts on your 454. You need to make sure you get all the accessories with the 8.1. You also need to figure out how your brakes work. Most likely your old 454 had hydro-boost that ran off the power steering pump. I have no idea what the 8.1 uses. Obviously, you'll need all the electronics and harnesses, including the fuel pump. That gets a little trickier because the newer engines had the fuel pump in the tank. Your best bet is to just buy an after market electronic fuel pump. The ECM is counting on a transmission, so you will have to have a 4L80E. You may be able to find someone to reprogram the ECM to ignore the trans, but it will still need a speed sensor.
I hope LYLE sees this, he also has an '82 Revcon and is ~90% done converting to an 8.1 he bought from Workhorse. He can give much more detail about what is involved.
If you want another alternative, go for a 502 short block and install an after market FI. You can buy a 502 crate, but get the Vortec heads or Edelbrock heads. Just make sure you get Fast Burn heads. For FI, you can use a '95 GM ECM. The chip for that computer is well documented. All the info is available for free on the net. That is the ECM that I am running. It will run you around 300 bucks for all the tools to burn your own chips.
* This post was
edited 07/02/09 09:25pm by Daveinet *
Dave
FMCA F298817
'83 Revcon Prince 31' FWD
502 w/Howell/Edelbrock MPFI, Thorley's & Magnaflows,
Koni FSD, Class A built for gear heads ?????? Revconeers Forum
There is nothing compassionate about taking someone elses money and giving to the poor.
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