Z28 springs on Vortec heads

[Slade88]

Hi everyone I bought a pair of vortecs

https://www.jegs.com/i/JEGS/555/514080/10002/-1

Linked here^

I’m pretty sure the springs on these heads are for a roller cam which I don’t have. I have a set of Z28 springs made by a company called engine tech, got them for 60 bucks on eBay. I am curious if I’d need any more hardware to use these springs on Vortec heads and whether I should use the secondary internal spring with the z28 springs to run a flat tappet?

I’ve also heard about a lack of coolant holes in the Vortec heads, or they flow coolant differently. My L05 engine has the third hole drilled at the water pump, does this mean I’m good to just drop the heads on and go?

I’ve already got a duel plane intake with a tbi carb adapter, will order the head bolts and gaskets and spark plugs soon so I’ll probably be doing this in a couple weeks, is there anything else I need to buy or know about a Vortec swap on an 88 TBI L05 350 engine thanks!

 

[L31MaxExpress]

The Vortec heads are not drilled for the water bypass port at the deck surface. Therefore, the hole in your block and water pump are blocked by the cylinder heads at the head gasket. I have not once plumbed a water bypass using vortec heads on an older block. If the heater circuit has continuous flow, a bypass already exists. In the case of a vehicle without a heater core, I drill the thermostat itself. An added external bypass is just another leak point as well as a way for hot coolant to be recirculated back to the inlet of the water pump and back to the engine without going through the radiator. On a factory Vortec the external water bypass is blocked off when the thermostat opens.

 

[Slade88]

The Vortec heads are not drilled for the water bypass port at the deck surface. Therefore, the hole in your block and water pump are blocked by the cylinder heads at the head gasket. I have not once plumbed a water bypass using vortec heads on an older block. If the heater circuit has continuous flow, a bypass already exists. In the case of a vehicle without a heater core, I drill the thermostat itself. An added external bypass is just another leak point as well as a way for hot coolant to be recirculated back to the inlet of the water pump and back to the engine without going through the radiator. On a factory Vortec the external water bypass is blocked off when the thermostat opens.

So if my truck has a heater core (which it does) I can forget about drilling anything? Thanks for the info man

 

[Slade88]

The Vortec heads are not drilled for the water bypass port at the deck surface. Therefore, the hole in your block and water pump are blocked by the cylinder heads at the head gasket. I have not once plumbed a water bypass using vortec heads on an older block. If the heater circuit has continuous flow, a bypass already exists. In the case of a vehicle without a heater core, I drill the thermostat itself. An added external bypass is just another leak point as well as a way for hot coolant to be recirculated back to the inlet of the water pump and back to the engine without going through the radiator. On a factory Vortec the external water bypass is blocked off when the thermostat opens.

This is the video I’m referring to

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[Erik the Awful]

So if my truck has a heater core (which it does) I can forget about drilling anything?

No. Either drill your heads for the coolant bypass, or run the Vortec water pump and the appropriate external plumbing for the bypass.

Here's the coolant bypass. You really only need it on the passenger head, but it's a smart idea to drill both heads in case you ever have them off again and swap them up.

You must be registered for see images attach

 

[Slade88]

While I’m at the machine shop do y’all think I should go ahead and get my heads ported? What should I get them ported to? Machine shops for 350s in general are hard to find in my city I’ll have to search a bit

 

[L31MaxExpress]

So if my truck has a heater core (which it does) I can forget about drilling anything? Thanks for the info man

Correct if it has a heater core that flows continuously, despite what others say, you do not need to add a bypass.

 

[L31MaxExpress]

No. Either drill your heads for the coolant bypass, or run the Vortec water pump and the appropriate external plumbing for the bypass.

Here's the coolant bypass. You really only need it on the passenger head, but it's a smart idea to drill both heads in case you ever have them off again and swap them up.

You must be registered for see images attach

Simply not needed if it has coolant flowing through the heater core. Complete and total waste of time on a GMT400 where the heater outlet flows continuously.

If you are that worried about it put a small hole in the thermostat.

The internal bypass never gave even cooling flow to both banks.

 

[Erik the Awful]

I got temperature spikes until I swapped to the Vortec water pump, and others have reported the same. YMMV.

 

[Schurkey]

If this were me--and it isn't--I would drill the heads. Simple, easy, factory-authentic. Worked acceptably well on millions of SBC engines prior to '96, and various crate engines post-'96.

That said, the heater core would work as long as there's no heater-control valve in place. Far as I know, that's not a concern on unmodified GMT400 vehicles; but some folks add heater control valves for their own reasons.

Never liked drilling thermostats, but if the other bypass options aren't used, that's a valid method of allowing controlled circulation when the thermostat is closed. It's the LAST option I would use. Drilling bigass holes in thermostats when there are other bypass methods is nuts.