1972 K10 --Help me decide 5.3/4l60E swap or 700R4

[suburban99]

Hey all, just picked up a 1972 K10 custom deluxe in decent shape. Currently 350/350 and runs great.
Recently rebuilt engine and tranny by PO..running 33"x 9.50 x15 tires and it has a lot of power so I suspect it has 4.10's

I am trying to decide whether to do a 5.3/4l60e swap or just replace the tranny with an 700r4 (or 2004r---have core). Trying to get the rpm's down a bit and mileage up. I did a 5.3/4L60e swap on my 62 C10 before I sold it and it was great..I can do the re-pin of the pcm...

Anyone care to share their 700r4 or 5.3/4l60 mileage numbers? Thanks

[Bigdav160]

200-4R is out unless you want to invest in a divorced transfer case.

The 5.3l/4L60e is popular but more work and expense in 4WD due to the vehicle speed sensor adaptation.

700R4 needs the engine moved forward, exhaust extended, radiator hoses shortened and a special output shaft to mate to the transfer case.

I don't have any mileage figures from my Suburban. Sorry

[jocko]

Concur 2004R best option.

[TwoFiftyShifter]

Keep it 350! How about an NV4500 swap for OD?

[72again4x4]

If it runs great, why not leave it and put a gear vendors OD unit on the output. This from a guy that pulled a 350 and put a 700r4 in my 72 K10.
Should a, could a, would a. Just my 2 cents.

[XwalkerX]

i have an L33 5.3/4L65e combo in my 2wd swb

blackbear performance tune
cold air intake
headers/x pipe/flowmasters
3.42 with eaton posi

I drive about 400-500 miles a week and avg 23 mpg

[72_K10_Vegas]

X2 with Bigdav160.

I have done all that he indicated to have the 700R4 installed (not on the road yet).

A guy should consider front driveline issues coming up with clearance to 700R4 pan. I did a 2.5" lift (actually 3 when it was compared to original) and that helped a little on clearance issues, but still will have to have a custom front drive shaft.

Not a huge deal, lots of competent shops out there, just one more thing....

[DeadheadNM]

Very nice truck. I went with a 700r4 in my k20 and have a th350 in my k1500 ( w 3.73 gears) both w 33" BFGs. I can't give you mileage though sorry. Unless you expect to do a lot of driving I'd suggest sticking w the th350 and change gears as needed to drop the rpms.

[Nitis]

I personally would explore the 700 r4 first

going with an LSX swap requires a new front crossmember and lift which it looks like you are already lifted

Either way your spending a lot of cheddar depending on how much work you can do yourself

[jeffahart]

The work is hard,
The pay is low,
But we're still here,
Still on the go!

The payloads high,
the gears are low,
Average speed is very slow!

My brains gone soft,
my liver hard,
your best MPG is parked in the yard!!!!


SBC....