Y pipe differences

[Firewood truck]

Hello everyone. I am gathering parts to get ready to do the engine swap in my beater. My truck- '88 K2500 6 lug, 5.7 TBI, SM465 trans. My donor engine is from a '98 K2500 8 lug, it was a factory crate replacement engine that has about 55K on it. I have snagged a GM performance intake so that I can retain the TBI. My plan is to just use the GMPP intake, swap over the TBI distributor and simply not plug in any sensors that the Vortec used that I don't need. The Vortec engine is just basically becoming a long block to be used in the TBI truck.

My big question is about the Y pipe on the TBI engine- does it physically bolt up to the Vortec exhaust manifolds? I've read a bunch of threads that skate around this question, but never see a hard answer about if it will or won't physically bolt up. I see the "dual" down pipe setups in the Walker exhaust catalog used on the K2500/3500, but then I see a single Y pipe on some K1500's that have a different p/n then those used on the TBI engines. I don't want to spend any $$ for the "correct" Y pipe if the one that I already have will work. Thanks for any info!

 

[Moofus02]

The over 8600 gvw trucks seem to have a bigger diameter head pipes on the y pipe. That said your y pipe should work fine.

 

[Moofus02]

I've put vortec head pipe on 95 k2500 tbi motor and vice versa to check fit

 

[Komet]

The Walker 40295 bolts up to vortec exhaust manifolds, so I'd give that a solid probably.

You'll want to swap over any TBI sensors that are different. Seems like the vortec temp gauge sender reads low in the TBI cluster.

 

[Firewood truck]

Thanks for the replies. I'm hoping to be able to use the Y pipe that's already there.

What about intake gaskets for the GMPP intake? I'm guessing stock Vortec gaskets? Also, I've never seen this mentioned- since my truck has the SM465 trans, I know that a 12" clutch and flywheel will bolt to the crank with no problems, has anyone tried the bigger 14" clutch to know if it fits inside of the SM465 bell housing?

 

[Moofus02]

Belive it or not I've always had much better luck with the smaller car clutch in the square body 4 speed 4x4 than the 11 out 12 inch clutch. Don't know why

 

[Schurkey]

What about intake gaskets for the GMPP intake? I'm guessing stock Vortec gaskets?

Does the GMPP manifold have the coolant passage under the plenum, from the thermostat area to the rear of the manifold?

 

[Erik the Awful]

The Vortec intake pattern has larger ports, so you'll need a Vortec gasket. The factory plastic gaskets are problematic at best. Get gaskets that aren't plastic. Hopefully someone else can post a link to a gasket they have experience with.