How to Put a Vortec Motor in a TBI Truck

[Schurkey]

IF the heads and the block is drilled for the coolant bypass...

...don't you have to run a TBI water pump, because the Vortec pump doesn't cover the bypass opening in the block?

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You'd either have to thread the opening in the block and cram a plug into it--flush--so there's no way it can interfere with the water pump mounting; or you'd have to leave the head un-drilled so there's no water in the block bypass passage to begin with.

This is the block that's in my truck now, with a TBI water pump and non-Vortec heads. I drilled the bypass hole and also the two bolt holes for the timing cover. (No photo of the timing cover holes after drilling and tapping, though.) You can see where the Vortec water pump doesn't cover the bypass opening.

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[Erik the Awful]

Good point. The heads on the motor in WCJr aren't drilled, and I'm running the Vortec water pump, but I went ahead and installed a plug in the bypass hole on the front of the block. Basically, I tapped threads, hacksawed a slot in some all-thread, RTV'd it, and screwed it into the block.

 

[rebelyell]

I won't bet on it, but suggest the tall-deck BBC truck 427T motor may require more torque; because 427T piston has 4 rings, not 3.

 

[rebelyell]

I have Vortec heads on an 880 TBI block in WCJr. I did not know about the bypass when I built the engine; it was my first SBC build, so it's not drilled. That's why I switched back to the Vortec water pump.


That sounds like the big block Caddy thermostat. If you run a normal thermostat in its place you get overheating.

Checking RockAuto... Yup. Same style, but apparently different size.

Vortec - https://www.rockauto.com/en/moreinfo.php?pk=3952968&cc=1353327&pt=2200&jsn=1056
Caddy - https://www.rockauto.com/en/moreinfo.php?pk=4483863&cc=1409374&pt=2200&jsn=1227

I learn something new every day!

Yup, both t'stats share same design/style. I don't recall working on a late Caddy. But when I look at the Vortec t'stat application list, I see it's also identical t'stat used in late (Panther chassis) Towncars and Crown Vics. I also have a couple final gen TCs w/ that 4.6L SOHC V8. I now recall how I had once thought the two t'stats (each w/ lower disk valve) looked a lot alike; well, I see now that's because they Are same. I never had cause to pull them in order to compare side-by-side; but they're clearly same.
I too learn something new!