Gen 6 454 Questions

[00CrewCab]

Ok, so my 2000 K2500 454 has spun a main and or rod bearing. Don’t have the tools to do a rebuild. Found lots of Gen 5 454 motors for 600-1200 but can’t find any Gen 6 around me. So main question, can I used a G5 engine in place of my G6? What’s the difference between the two? I’ve heard cam’s are different. And a few other things. But what would I need to change on the G5 to work like my G6. This would be a temporary swap while I get the tools and parts to rebuild the G6. Thanks all.

 

[618 Syndicate]

@Dropped88

 

[454cid]

The gen5 is a tbi engine. I believe the intake manifold from the gen6 would physically swap, but you'd probably need a custom tune. The gen5 has a lower compression ratio, different heads, and possibly lacks the spot for the crank sensor in the timing cover for the gen5 multisport fuel injection. Seems like a lot of money and effort for something temporary.

 

[Supercharged111]

GenV is hands down the worst 454 ever made. That's why you're able to find them. I wouldn't touch one with a 10 foot pole. They're gutless and they overheat. Just hold out for a GenVI.

 

[Schurkey]

Gen V short-block, the heads, intake, and front cover/crank sensor/crank reluctor from your existing engine.

You'd need some gaskets 'n' sealer, a decent 3/8" torque wrench, an engine hoist and a fair bit of courage.

I put Gen 6 heads on a Mark IV block; the head gaskets I chose were not optimum. I don't think that'd be a problem with a Gen 5 block, though. Note that I've never actually done that swap.

 

[Supercharged111]

Gen V short-block, the heads, intake, and front cover/crank sensor/crank reluctor from your existing engine.

You'd need some gaskets 'n' sealer, a decent 3/8" torque wrench, an engine hoist and a fair bit of courage.

I put Gen 6 heads on a Mark IV block; the head gaskets I chose were not optimum. I don't think that'd be a problem with a Gen 5 block, though. Note that I've never actually done that swap.

I'm under the impression you need special head gaskets to put anything other than a GenV head on a GenV block. MarkIV and GenVI are indeed compatible. It's an absolute b@$t3rd of an engine. And you're still stuck with a flat tappet cam.

 

[00CrewCab]

The gen5 is a tbi engine. I believe the intake manifold from the gen6 would physically swap, but you'd probably need a custom tune. The gen5 has a lower compression ratio, different heads, and possibly lacks the spot for the crank sensor in the timing cover for the gen5 multisport fuel injection. Seems like a lot of money and effort for something temporary.

That’s what I was afraid of, I found a couple GenVI engines, but they all are have either bad crank/rod bearings or they want $2k or more. And at that price it’d be cheaper for me to buy the tools and parts I need for the job and do it myself.

 

[00CrewCab]

Gen V short-block, the heads, intake, and front cover/crank sensor/crank reluctor from your existing engine.

You'd need some gaskets 'n' sealer, a decent 3/8" torque wrench, an engine hoist and a fair bit of courage.

I put Gen 6 heads on a Mark IV block; the head gaskets I chose were not optimum. I don't think that'd be a problem with a Gen 5 block, though. Note that I've never actually done that swap.

So find a GenIV block and not an GenV? Would I swap in my oe GenVI cam and lifters since I’ve heard the GenIV flat tappet isn’t the best? If I could find just a good bottom end/short block GenVI I’d swap my heads on it, but most short blocks are all rusted junk.

 

[Supercharged111]

So find a GenIV block and not an GenV? Would I swap in my oe GenVI cam and lifters since I’ve heard the GenIV flat tappet isn’t the best? If I could find just a good bottom end/short block GenVI I’d swap my heads on it, but most short blocks are all rusted junk.

I believe you need special head gaskets to put a non GenV head on a GenV block. And the GenV block is not OE roller compatible.

 

[Schurkey]

There are (were?) special head gaskets--different part numbers L and R--to put Mk IV heads on a Gen 5 block.

Far as I know, (and I could be wrong) the Gen 6 heads drop onto a Gen 5 block as-is. I don't know if you'd need Gen 5 or Gen 6 head gaskets, or if there's even a difference between 5 and 6.

When the Gen 6 came out, folks were calling it "Gen Fix" because they finally fixed most of the screwups they introduced with the Gen 5.

I've been away from BBC for a long time. I'll have to dig into the Mark IV boat engine next spring (but that's what I said LAST fall.)