The official 6bt conversion thread

[mljjones67]

Dustin that is awesome. I like the 35 mpg. So I guess for everyday driving you turn the injector pump down and save fuel then when towing crank it up and tow the heck out of it. Will that work???

[Redcap]

FE and 4BT weigh the same, 550 pounds. Alternator and PS pump probably weigh pretty close to exactly the same since they are exactly the same.

a 460 weighs quite a bit more than a 4BT and guys stuff them in 1/2 tons all the time. Stock springs should work great.

Wow!

Any idea on the weight of a 6.9L IDI?

[averagef250]

I think the 6.9/7.3 is around 1000-1100 isn't it? As far as turning the pump up and down goes, I don't think that's practical for most people. The adjustments on the pump aren't parts that are designed to be fiddled with all the time. Although much simpler, a diesel pump is still similiar to a carb or EFI in that the fuel deliver needs to be correct for the air moving through the engine. This 4BT is not "in tune" and I honestly wouldn't be driving it as gutless as it is. It's get on the freeway at 45 floored gutless.

My redneck dynomometer is a small hill on a country road close to my house. I've run many vehicles on it over the years. A 13 flat quarter rig will run about 95-100 at the top, a 400 horse big block in a 4x4 should run about 75 at the top and so on. My '71 did almost 60 at the top before governor and pump mods. This latest 4BT truck with the same exact running gear threw down a whopping 40 MPH!

[mljjones67]

Well thats ok the 4bt is still the way to go. I definitely want it above 40 mph

[mljjones67]

Check out the double turbo this guy is doing!!
http://www.4btswaps.com/forum/showthread.php?t=880

[xxxtina63]

Personally, I kind of like the idea of 30 mpg, just so long as it's not freaky slow. My spare car, an '87 chevy truck, which is in sorry shape, is much slower than my Neon, which is rated at about 135 hp. In fact, it's almost a challenge to get it up to 60 mph. I don't expect a 4BT to run like the Neon, but I don't require a hotrod either. Mostly I'm looking for a happy medium. A daily driver, at least in the summer, that can run at highway speeds and occasionally tow a descent, heavy load. Does this sound like I'm on the right track?

[averagef250]

That's what the 4BT does stock, but 30 MPG isn't realistic for a 5000 pound truck. It was WAY to slow for me. I won't drive a rig unless it can get on the freeway at freeway speed. The last non-ford truck I drove was a '79 K30 with a mild 350. Geez what a turd. Had it pinned in third every time getting on the freeway. I hated the truck and drove it that way. I remember towing one time I just threw it in 3rd and held it just below valve float. All that truck was good for was getting stuck.

[xxxtina63]

Yeah, the 1/2 ton 2wd TBI 305 chevy gets about 9-11 mpg. Miserable . With the hybrid cars getting 30 mpg, I want my next build up to last a good long time. They're worthless if you only get 9-13 mpg. Can't afford to drive them anymore. Guess I figure, despite the initial cost, I'll be ahead in the long run with around 30 mpg with a 4x4. No sense building up a truck you can't afford to drive . And, with that kind of mileage, it's light years ahead of anything the big 3 have to offer.

[mljjones67]

Check out the double turbo this guy is doing!!
http://www.4btswaps.com/forum/showthread.php?t=880

[averagef250]

I think most go with the 12 valve before they ever consider twin turbos on a 4BT. That's allot of work, testing, tuning and money that might be wasted.

I'd stuff a DT466 in something if I had one laying around. Is there a way to bolt the DT466 to a ford diesel bellhousing and 1 3/8" 10 spline clutch? That's probably a bad idea anyway. A pickup tranny can't handle that power or weight.

[nevrenufhp]

I'd stuff a DT466 in something if I had one laying around. Is there a way to bolt the DT466 to a ford diesel bellhousing and 1 3/8" 10 spline clutch? That's probably a bad idea anyway. A pickup tranny can't handle that power or weight.

Only possible if the Ford bell was an SAE#2 or 3. The 466 comes with a #2, and you can adapt down to a 3. If you were only drag racing it, a C6 might live a few passes.
1400 pounds is a lot of iron. A DT360 may be an alternate, it's about 200 pounds lighter, but is even more robust than a Cummins 6BT. While not as tall as a 466, nor as long, it's the same width. Would be kinda neat to blast past Maddog with his 1100hp Cummins F350 in an 1100+ hp DT360'd Bump!

[averagef250]

How do the 80's/90's Eaton medium truck 6 speeds shift? I've seen a few of them for sale locally and wondered if they'd be worth picking up for a future "too big for a pickup" diesel engine swap project.

I won't run a slushbox myself.

[nevrenufhp]

Eatons are good, Spicers break a lot, and stay away from any med. duty 5 speed.

[averagef250]

Good to know.

There's a nice body, bad 361 1970 F-600 short wheelbase little dumper a mile down the road from the house. Sat there for the last 15 years and the guy won't sell it. He's in his 90's so I know I'll outlast him. As soon as he goes I'm getting that sucker from his family! I'm thinking 5 ton rockwell toploaders under it, a DT466, 6 speed would be a lot of fun to put together.

[Mooosman]

I've seen a few 4BTs on eBay the last few days that have a Ford 4 speed behind them. It looks like an NP435 from the pictures. Any ideas on what these 4 speeds are?

I'm assuming that the trucks that have Ford trannys originally had 300 sixes in them, and then were converted? If this is the case, will normal 300 six clutch parts work?

Nick