Gen VI BBC oil filter adapter

[Bill Chase]

Engine is from k3500 chassis and has the sideways filter Mount. I need old style vertical filter Mount to fit the gmt400 c1500 chassis & getting conflicting info. Can anyone confirm 3853870 is all I need to run a standard 51061 filter on it?

[BillK]

That looks like the right one. The bypass is built into the block. Why not have your local dealer look up the part number for the truck you are working on just to be sure ?

[Bill Chase]

That looks like the right one. The bypass is built into the block. Why not have your local dealer look up the part number for the truck you are working on just to be sure ?

Removed from a 2000 GMC k3500 over 8600 gvwr truck, installing in a 97 c1500 chassis, gm never put a big block in the 96-2000 gmt400 c1500 chassis except for the earlier 90-94 454ss (c1500chassis gmt400) and it was a gen 3and4 BBC block. L29 was only used in c/k 2500, 3500 and commercial chassis in 96-2000. The dealers around here will only know what works with something gm actually released to the public. And trying to get them to look up stuff over 15 Years old is akin to root canal at a sadistic dentist's office.

[BillK]

Bill,
I have the engine out of a 2000 C30 sitting here. It has that fitting in it. I just looked it up on GM Parts Giant and that is the same part number So you should be good to go.

https://www.gmpartsgiant.com/parts/gm-f ... er=(e=L29)

Too bad your not close by. I probably have 5 of those fittings that I have scavenged off junk Mercruiser blocks.

By the way, take a look and see if yours has a bypass valve in the center right above where the fitting goes. If it does you want to take it out. It improves oil flow tremendously and is only needed with the remote oil cooler that is plumbed into the block along the oil pan rails.

[Bill Chase]

So run it without a filter bypass? This is just going to be a hop around backup vehicle, and I live in Michigan, I am ok not running a bypass as long as it doesn't require extended warm up times. I'm not changing anything with the tune. Swapping the ECU and wiring harness from the 2000 it's a direct swap into the 97. Interesting note is the k3500 hd trucks didn't have airbags in 2000, and as near as I can tell didn't have the downstream O2 sensors either. If they did someone tuned them out of this truck because it didn't have them when I got it, and it ran good, no check engine light and no wiring for them visible. It hasn't been hacked up so I can only assume the over 9200 gvwr heavy duty didn't require downstream O2?? 290 hp and over 400 tq at a lazy 4500 max rpm should make for a good little sport truck/hop around backup vehicle. think of it as the 454ss gm would've made had they did so in 1997. The truck began life as a base short bed c1500 4.3/4l60e w/10 bolt g80 Eaton locker and 3.42 gears. The donor is L29/4l80e, 4.10 gear 4wd. Have a buddy that rebuilds transmissions and owns his own shop, he needed the transfer case and a good 4wd 4l80e core, swapped him for a good 2wd 4l80e out of a 2000 express van. I put a set of springs in it from a 97 c1500 5.7 and it dropped the front almost perfect, looks like a 3-5" rear drop will level it out. Fun budget project, so far I only have 2 grand in the entire project. Super clean Arkansas truck that was purchased new by a rural school district for general maintenance worker use. Has air, cruise, power door locks and that's it. The donor vehicle was the same, but had a long bed. Makes swapping the entire wiring harness a breeze.

[BillK]

So run it without a filter bypass?

Bill,
There are two bypasses. The one on the flat surface is for the filter. That stays in place. The one in the center is only for use with the external cooler and is there in case the cooler clogs up. If you leave it in the oil has to go through a couple of passages and makes a u-turn before going into the engine. Taking the center bypass out just gives the oil a straight shot from the filter into the engine. I have seen some engines with the center bypass and others without. We always take them out on the Mercruiser engines unless they are using the remote filter setup that plumbs into the block.

I think there is a thread on here that goes into more detail.