DoubleRed89GMT400
Newbie
I am interested in finding out how difficult a 24V or 12V swap would go replacing it from a former 1989 350 EFI. Truck has the 4L80 transmission to my knowledge.
How would a 24V or 12V Cummins swap go for a 1989 Chevy 2500.
- Thread starter DoubleRed89GMT400
- Start date
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454cid
Sooper Pooper
You might want to look into the transmission compatibility. I believe the Cummins makes torque lower than what the transmission can handle, due to pump pressure not being great enough at that low rpm. It may only be an issue for the th400, but its better to check and be sure than too get half way into a build and have to change plans.
4btswaps would be a good place to explore.
Also....I think an 89 would be a th400, not a 4l80e.
4btswaps would be a good place to explore.
Also....I think an 89 would be a th400, not a 4l80e.
CumminsFever
I'm Awesome
I've done both 4bt and 6bt into the gmt400. I used various parts, including fabricating my own mounts. The best and easiest was when I used autoworld conversions parts.
I simply called autoworld and told them the year engine I had, and what truck it was going into. They sent motor mounts, a/c and alternator brackets. I used patc bellhousing adapter for 4l80e, us-shift trans controller, and it worked very well.
It isn't "plug-n-play" to do such a swap, but it isn't nearly as difficult as you'd think. Transmission MUST be built. I recommend jakes transmissions build for 1000ft lb torque. This assumes using 4l80e.
The most difficult thing is getting driveshafts set to correct lengths. Yes, transmission gets slid back about 2 inches.
I simply called autoworld and told them the year engine I had, and what truck it was going into. They sent motor mounts, a/c and alternator brackets. I used patc bellhousing adapter for 4l80e, us-shift trans controller, and it worked very well.
It isn't "plug-n-play" to do such a swap, but it isn't nearly as difficult as you'd think. Transmission MUST be built. I recommend jakes transmissions build for 1000ft lb torque. This assumes using 4l80e.
The most difficult thing is getting driveshafts set to correct lengths. Yes, transmission gets slid back about 2 inches.
Out of curiosity, how capable is the 4BT for towing? That's one of those swaps I always thought would be cool, but others told me they didn't think the 4BT was big enough.
CumminsFever
I'm Awesome
So, I've done a couple 4bt gmt400 swaps. My personal truck was a '92 k1500 reg cab. The truck dyno'd 496hp at the wheels. I towed above max truck capacity with it, and the good old 10 bolt rear axle held like a champ. I did flex the frame enough that the windshield cracked. So that's an issue on the 1500 trucks!
Another one I did was a '95 k2500 ext cab. Nv4500 double overdrive, set at 275 flywheel hp, it towed a 30ft lawn mowing trailer with ease, and empty truck got 29mpg when I took it on a trip.
All in all, I'd tow with a 4bt, just understand it is a 4cyl, it needs a little more rpm than the 6bt to make it's power. Slightly vibrational, but injection pump tweaks and fluid dampers work wonders on these things.
For a 1 ton truck, I would NEVER use a 4bt. Continuous wringing at max effort does cause shorter engine life.
Hope this helps give you a little insight on what a 4bt "can" do.
modernbeat
I'm Awesome
Is Auto World still around? Looks like their old site is gone.
someotherguy
Truly Awesome
'89 is definitely a TH400, not 4L80E (didn't come out until '91) .. so considering no overdrive, also look at what your rear axle ratio is - then use the simple online calculators to determine what your RPM's will look like at typical highway speeds...and then look at the redline of the Cummins engine you're considering. Just an FYI. You'll probably want an overdrive transmission and might be looking at a re-gear on the rear, depending.
Richard
Richard
CumminsFever
I'm Awesome
Well, it was about 10yr ago that I used autoworld. I haven't done a repower for someone else since then, so I haven't actually checked to see if they're still around. When I do my own, I make my own stuff.
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