Originally posted by MikeN
If I would have stayed with the automatic already in the truck, I think I could have pulled it off for under $4000. Since I am also swapping in a NV-4500, its going to cost me a bunch more.
I'm doing all the work myself. I don't know what it would cost to have somebody else do it, but a good rule of thumb is about double what the parts cost.
I drive 200 miles per day, so I am hoping to recover some of my cost in lower fuel expense. My truck with the 350 gets about 16-17mpg, I'm hoping I can get 30 mpg with the 4bt. [/B]
Your mileage with the 350 seems strangely high, I have at best gotten 14 with most GM trucks I have had. Then again, I have not owned a 2wd truck with the exception of my wife's 99 mazda in over 12 years. If you're really getting that kind of mileage, you may want to consider leaving the truck alone and just maintain it. Most 4bt conversions I have done have been for off roaders or
Mileage will be better just by getting rid of the automatic. Using the stock automatic will require having it reworked for different rpm shift points anyways, hardly worth it for a 700r4. Even the turbo 400's are a questionable transmission for daily driving. Most p-30 panel vans were equipped with the manual transmission's for a reason.
Swapping in the NV-4500 will benefit you in the long run, especially if you buy a brand new one for reliability. You'll have an overdrive that will keep your highway rpm's down. You can easily refit the truck with a stock clutch pedal assembly.
Going by previous friends/customers with the 4bt's in their GM pickups, You should expect at least 25 mpg or better.
Doing all the work yourself is one of the best way to keep costs down as long as you research parts needed and don't find out half way through you can't get something to fit. That's when the budget goes out the door. Do it yourself conversions are also a good way to go insane when you have problems as you have no else to blame. I don't know your abilities so please don't take this wrong. It is really frustrating when you spend weeks with your truck in pieces and then find out you need outside help to finish something, which will usually require more money spent as they have to go through all your work and make sure it is right, or worse start over. If its a daily driver, can you be without for a month? I have had the most repetitive conversions take that long thanks to outside work such as driveshaft work, exhaust shops, or transmission shops reworking automatics to shift right, etc. This is not a deterence, just a point that planning and research is critical before you begin.
Snowman has a very, very, valid point. It is what I tell most friends and customers doing the conversion for mpg. The only times I usually agree to gm conversions or ford's is when the folks have a crew cab and can't afford a brand new dodge, or don't have faith in the newer 24 valves like me. Extended cabs are a waste of money as I can pick up a late model dodge ext cab for under $10,000 now.