motor specs. 454 gen iv and v

[wb13798]

what is the difference between the gen iv abd genv engines??? one thing the gen v requires a electric fuel pump. can not mount a mechanical fuel pump.
will water pump and intake manifold interchange?? will ac brackets interchange??? not worried about the exhaust manifolds they is going to goo away headers to be installed.
one other piece of info the gen V was used for 86 to 96 truck engines.
how much pain will it be to put in my 84???

[JanP]

Don't know the difference, but my 1984 454 has a mech and elect fuel pump. The mech is on the curb side near front of eng.

Ernie and Jan

Cougars to end.

[smily]

Mine does not have a mechanical pump. It has a cap over the portal.

I dont see where there would be any problem with a mechanical pump though if it were there.

Smily

[FireFighter]

Even though the port is on the block I don't think the cam has the lobe to drive the pump, I could be wrong someone else chime in here.

[74Argosy24MH]

A mechanical pump is low pressure, the booster pumps on the pre FI are also low pressure. Fuel injection uses higher pressure than a mechanical pump will put out reliably so it was eliminated, including the cam lobe. If you look it probably doesn't have threads or even an opening, just part of the casting now.

The gen v block is and isn't the same as the previous blocks. Heads, manifolds won't work, cooling passages are different.

John

[59toaster]

Originally Posted by 74Argosy24MH

A mechanical pump is low pressure, the booster pumps on the pre FI are also low pressure. Fuel injection uses higher pressure than a mechanical pump will put out reliably so it was eliminated, including the cam lobe. If you look it probably doesn't have threads or even an opening, just part of the casting now.

The gen v block is and isn't the same as the previous blocks. Heads, manifolds won't work, cooling passages are different.

John

I thought the heads would bolt on? THey did change the heads I know but I thought they would still work. I thought the difference was where the intake bolted on. This is On the FI 454 motors after 89. They change the bolt pattern on the inner 4 intake bolts. Same deal they did with the 350's. The block changes were to the oiling system to fix the issue with the cam not getting enough oil at times and causing flat lobes.

[wb13798]

just found my service man and his thoughts are . since this is a gen V long block with tin. i need to add the intake and the gen iv intake will fit along with the water pump, alt and ac brackets. exhaust manifolds might not fit but i plan to replace with headers.
the fuel pump wont work unless you change the cam no lobe for the pump no push rod .
i have a elect pump back by the fuel tank .10 gph 9psi max. i think that is the spec for the pump.
what do i do with the return line???
i don't have this motor yet. it is a gm crate motor new not Refurb. i will have to replace the cam it is for a truck not rv not a big deal. summit and jegs has a good variety to choose from.

[wb13798]

i guess the only open question is the intake manifold. don't think that would be a big bucks item to replace as long as the carb works on a new manifold.

[swebster]

I think you can get an aluminum manifold from Summit or Jegs for about $200. Pretty sure a spreadbore will accept your QJet.

[wb13798]

just been advised old intake will fit. the biggest difference in the two motors heads will not interchange. and the fuel pump issue.

[74Argosy24MH]

The fuel pump is not really an issue, just use another low pressure one near the engine.

John

[mcneon]

The early 454 intake manifold will fit the Gen V 502, as will most any other 454 manifold. If I recall correctly, we had to remove the splash tray on the underside of mine, but there's a tray mounted in the 502 valley that keeps oil from splashing on the mainfold. (Purpose: to keep oil from cooking on the bottom of the intake manifold exhaust crossover.)

There's no machining for a mechanical fuel pump. I don't know if the cam has a lobe to drive a pump, but there's no good reason to find out. Plus, if you change to fuel injection, it's a moot point anyway.

All other accessories bolt right up, except you'll have to re-plumb your oil cooler; the original oil cooler adapter won't fit the 502. See this link: http://www.greenwoodchevy.com/engine1.htm for details. You also have to use the small gear-reduction GM starter.

If you stick with the factory 502 truck cam, you'll also need to change the distributor drive gear to a heat-treated one from GM. There's some incompatibility with the steel cam and the original gear. I'm not sure there's much advantage to changing to an "RV" cam. The standard 515 lb-ft @ 2800 RPM with the truck cam is about perfect for our application.

According to the GM Performance Parts catalog, heads are pretty much interchangeable, but there may be reasons you wouldn't want to do this. I highly recommend getting a copy of this book from your local GM dealer - tons of good info in there, and the source is unimpeachable.

Bob McKeown

[dinoburb]

Hi wb13798,

I have been reading this thread with interest. However, I can't tell which Gen V long block are you looking at installing? Mark IV and Gen V engines both are available in 454 configuration. 502 is not available in Mark IV block flavor. If the engine has not been actually purchased the 338HP/512lb.ft., 502 engine for towing should be your number one choice. Do not change the cam as max torque is at your probable cruise speed (about 2800rpm as stated above). External fuel pump will be required as will a proberly jetted and needled Q'jet. Q'jets ARE spreadbore carburetors and they are very well designed. JET Corp makes tailored carbs; just call and discuss your engine with them. They'll build a carb just for you. If money is no object (!!??) then look at the Holley 950 Commander fuel injection system. It's simple, reliable, and tuneable which is not a bad combination. MSD Distributor for steel cams is advised.

Hope this is of some help.

Take care,