454 vortec heads

[prairiehotrodder]

i just picked up a complete stock 1997 Gen 6 chevy 454 vortec engine. The roller cam was mucked up on a few lobes but the rest of the motor looks allright. Anyways i want to know about the heads. Are they any good ? Apparently they have a 100 cc chamber which makes them nice to swap on to an older flat top piston motor to gain some compression. Can this be done ? Are there coolant passage issues ? Can the valve train be changed to adjustable ? To eliminate the bolt-down rockers ? I'm sure i could spend a half a day searching for answers on the internet but i come here first.
Thanks

[F-BIRD'88]

There is a special head gasket that allows gen V heads on Mark iv block.. Yes the rockers and studs can be changed to convert to adjustable like a mark iv bbc.

[FC-Pilot]

Yes, the Gen VI heads will bolt onto Mark IV stuff. Also, ARP makes a rocker stud that bolts right in to convert to adjustable rockers. As to the flow and potential of the heads that I do not know. The Gen V heads were a little more of a sealing issue, but they fixed that for the Gen VI.

Paul

[Schurkey]

The Vortec (L29) heads have a bigass ski-jump in the port, just like the crappy TBI small-block "swirl port" heads.

About 5000--5200 rpm is their upper limit; I'm told porting does wonders. Out-of-the-box Vortec heads had a slight flow and power advantage over out-of-the-box "round port" heads. They were not the big improvement that the Vortec small-block heads were.

The chamber may or may not hit domed pistons. Depending on the piston, you may be grinding the chamber for clearance.

The L29 heads I've seen have valve rotators under the valve springs. You'll want 16 (two sets) of rotator eliminator shims. The shims may not fit perfectly on a few of the intake valve guides--the radius at the valve guide/spring pocket is not perfectly machined. A little clean-up with a grinder fixes this issue.

The heads have hardened seat inserts.

Flashlight in the intake port shows ski-jump for "swirl".


I used these heads on a Mark IV block in my boat. Conversion rocker studs, roller rockers, valve rotator eliminator shims. Mr. Gasket steel-shim head gaskets BARELY sealed a couple of water ports, which I found out when I disassembled the engine a couple of years later. Other Mark IV head gaskets probably worked fine--I didn't test any others. I had no leakage, but the boat doesn't have a pressurized cooling system. I got about 5200 rpm out of them--maybe 200 rpm more than the round port heads with leaky valves that these replaced.

[rustbucket79]

First thing you need to verify is the coolant holes in relation to the heads and block. No gasket will seal if it isn’t clamped on BOTH sides, regardless of what Fel Pro says.

[prairiehotrodder]

sounds like there isn't much performance advantage to these heads other than maybe gaining 1 point in CR on a JY flat top motor ?

[rustbucket79]

100 cc chamber on a stock 454 regular gasket undecked you’re in the 8.5 range, hardly worth the effort.

I did up a set of 366 truck heads with stock 454 valves, pocket ported on a fresh 454 with a mild cam on propane in a 1 ton 4x4, boy was that a disappointment, no discernible difference from the high mileage peanut port engine it replaced. I often considered reincarnating the Qjet but sold the truck before it happened.

[1980RS]

sounds like there isn't much performance advantage to these heads other than maybe gaining 1 point in CR on a JY flat top motor ?

Oh I don't if I would sat they don't have much advantage over let's say a peanut port head. People though I was nutz to put the 170cc Vortec's on my 406 SBC but I am glad I tried them, pushed the car into the high 10's with not a lot of work on them. Funny what works and what doesn't.

[77cruiser]

sounds like there isn't much performance advantage to these heads other than maybe gaining 1 point in CR on a JY flat top motor ?

Oh I don't if I would sat they don't have much advantage over let's say a peanut port head. People though I was nutz to put the 170cc Vortec's on my 406 SBC but I am glad I tried them, pushed the car into the high 10's with not a lot of work on them. Funny what works and what doesn't.

You didn't have the vortec's flowed did you?

[1980RS]

sounds like there isn't much performance advantage to these heads other than maybe gaining 1 point in CR on a JY flat top motor ?

Oh I don't if I would sat they don't have much advantage over let's say a peanut port head. People though I was nutz to put the 170cc Vortec's on my 406 SBC but I am glad I tried them, pushed the car into the high 10's with not a lot of work on them. Funny what works and what doesn't.

You didn't have the vortec's flowed did you?

Not yet, we have some thieves around here that think their time is worth gold and want mega bucks to flow a head these days. Next place I get I am going to get a flow bench and make some money off it like I did with my valve and seat grinder.