454 identification

[skymangs]

I need help identifying this engine. I know it's a 454, came out of a C7500 truck, but I've never seen a 454 with coil packs. what PCM and harness do I use?

[kwmech]

What year? could be an 8.1--- am I seeing an SAE bellhousing? Above the bellhousing on the drivers side is a casting number. Also, look on the side of the block between the engine mount and the bell

[skymangs]

it isn't LS based so it's not an 8.1, 99 C7500

[skymangs]

the throtte body is on the side like an EFI 454, not on the front like an 8.1

[skymangs]

it is an 8.1, thanks! for $400, I think I got a steal!

[68Gold/white]

Those were the last of the big blocks that GM put in any trucks, pickups, or medium duty trucks. I don't remember exact years, BUT the first couple of years engine that looked like that were 454's. Then came the 8.1, which is 495 cubic inches, it's NOT a 502! THese engines had LS technology used in them. There's actually nothing much in common with the classic big blocks that Chevrolet made since 1965.
Would make a cool classic pickup engine!!!

[skymangs]

yes it would ! according to googie, the only gas engine that was available in a 99 C7500 was an 8.1!

[57taskforce]

Originally Posted by skymangs

it isn't LS based so it's not an 8.1, 99 C7500

8.1’s are not LS based. They have far more in common with the 454 they replaced than any LS engine. They are good ole fashioned big blocks. And bad ass big blocks at that, much more desirable than a 454 in my opinion. The 8.1 is 496 cubes

This engine in question is likely the industrial version of the L29 454 which was found in the 3/4-1ton trucks from 96 to the changeover to the next body style, the L21 454 which is what I bet a dollar this one is was found in motor homes and the other big trucks. They had coils over the plugs like the later 8.1. The 8.1 didn’t come out until the 2001 model year just in time for the new 01+ Silverado HD, end of story.

One dead giveaway other than the year is the intakes. They look completely different that is a 454 intake.

[skymangs]

well I guess google lied! at $400 I still got a smoking deal!

[skymangs]

lf it is a 454, then a regular big bock roller RV cam should work

[Boog]

Have you ran the numbers on it and seen it run? It has seen some miles by the look of it. A compression test is a good idea.

[skymangs]

will run numbers tonight

[AussieinNC]

Here is a link to an interesting commentary on the 8.1 Vortec engine...

http://www.duramaxhub.com/gas/gm-8.1-vortec-l18.html

enjoy...

[TwoFiftyShifter]

Teenage girlfriends family had an 03 2500 Burb. 4x4, 8.1L.
For hauling horses. Very sweet ride.

[57taskforce]

I had a loaded 2001 K2500 suburban with an 8.1. Loved it. Torque for miles and miles. They make around 375 ftlbs at idle. I traded it off when I got my Camaro. Don’t regret the trade.

Originally Posted by AussieinNC

Here is a link to an interesting commentary on the 8.1 Vortec engine...

http://www.duramaxhub.com/gas/gm-8.1-vortec-l18.html

enjoy...

The only thing I see wrong here, is the 8.1 was Definitely offered behind the Allison. The trucks got the Allison and the Suburban and avalanche for the 4L85E. No SUVs ever got the ally. I also had an 06 K3500 with the 8.1/Allison combo. I thought you could get the ZF6 with the 8.1 too but I may be wrong.

[davischevy]

We ran an 8.1 engine to well over 300,000 miles.

We still have one in a K2500. It is our mechanic's shop truck. The Allison bit the dirt a while back. The only Allison we ever had fail.

The 8.1 is impressive in both it's power and lack of fuel mileage.

['63GENIII]

Originally Posted by skymangs

lf it is a 454, then a regular big bock roller RV cam should work

They're roller motors to begin with. Both the L29 and L21 have the same small cam and I've heard the same heads. The ones with the fast burn thing in the cylinder and the ski jump in the intake port. Coil per cylinder is good and I think that you can run the newer 0411 PCM instead of the black box that came before. Black box is a little limited for tuning. Ive heard that you will find H2O easily when trying to port the ski jump out and was advised to not mess with the sharp "fast burn" thing in the cylinder either. I have never heard it ping even though it drinks the cheap stuff whether towing or not.

Both are 4 bolt blocks with the L21 having some forged goodies inside.

Mine had supposedly had 80k on it when I got it and it looked like it had been pulled out of the bottom of a tar pit. The machinist said that it showed little wear, honed it, polished the crank, gave me the std. bearing, rings and gaskets and she has been running great since.

They're not super popular or common but a few members here including myself have had pretty good luck with the L29 and the 8.1. Cant remember if Ive seen anyone with the L21 though.

I still have to get it tuned for the injectors and cam but even on the "safe" break in tune, it pulls like a freight train. Doesn't wind up much but pretty sure that's the tune limiting it at this point.

8.1 would be real cool but 400 for an injected BB that has pretty good potential power and drivability isn't to be scoffed at either! I really like mine.

[LockDoc]

-
I have 3 8.1's, One is out of a motor home and has a Allison 6 speed behind it, 34,000 miles on it, one is out of a 2003 Chevy 2500 with an Allison 5 speed behind it, 134,000 miles on it, and my 2003 Suburban I drive has one with a 4l80e behind it, 191,000 miles on it. All I know is I don't have any problems pulling the trailer loaded, with the Suburban, no strain, no grunt, just go....

454 exhaust manifolds, bell housing and flex plate will bolt to them. As far as I know there is only one company making Carb intakes for them (Dart) and the 8.1 has provisions for using a distributor also.

If you want any info on 8.1 496 engines look up threads and posts by member "DirtyLarry".

LockDoc

[57taskforce]

My suburban had 271,000 on it when I got rid of it. I still
Made long trips in it frequently. My father in law has my old K3500, 230,000+ on it now with no issues. He drives it 150+ miles a day to work and back.
The L29 in my 98 K2500 still runs great at 207,000. None of them run very well at 4500 plus, they run out of air very quick. As said above The L29 and L21 both have really small cams that are degreed retarded from the factory for emissions reasons. A cam swap and proper cam timing wakes them up quite well, as does good injectors. (the Oe injectors are junk)

[skymangs]

all good to know, what injectors would you recommend?

['63GENIII]

Ive heard that a lot of folks run the Mercruiser Mag takeout cams and that they can be had relatively cheap. IIRC, there are no spring changes needed for this and this is relevant because the stock springs are pretty light. You can open the valves by hand.

There is also the non adjustable valve train to deal with when bigger cams / different springs are used. Not sure if a roller for a Gen IV - V block would fit as there is a cam thrust plate OEM and the cam does have the stepped nose. Original cam used the "dog bone" roller lifter guides with a sheet metal "spider plate to hold them down. The Morels that came with the Straub kit have the lifter pairs "tied" so that the dog bones and spider plate aren't used.

In my case I went to the an adjustable valve train, Chris Straub cam and 36# injectors. Like I mentioned before, I still need to get it a live tune to get back what's left on the table. Ideally, I'd get the later model PCM which is easier to log data and in the end tune.

For reference the stock injectors are 19# and along with the tiny cam are a pretty anemic combo. I don't think that they're suited for racing but I do think that a fair amount of reliable power can be coaxed out of these engines.

[57taskforce]

Originally Posted by '63GENIII

Ive heard that a lot of folks run the Mercruiser Mag takeout cams and that they can be had relatively cheap. IIRC, there are no spring changes needed for this and this is relevant because the stock springs are pretty light. You can open the valves by hand.

There is also the non adjustable valve train to deal with when bigger cams / different springs are used. Not sure if a roller for a Gen IV - V block would fit as there is a cam thrust plate OEM and the cam does have the stepped nose. Original cam used the "dog bone" roller lifter guides with a sheet metal "spider plate to hold them down. The Morels that came with the Straub kit have the lifter pairs "tied" so that the dog bones and spider plate aren't used.

In my case I went to the an adjustable valve train, Chris Straub cam and 36# injectors. Like I mentioned before, I still need to get it a live tune to get back what's left on the table. Ideally, I'd get the later model PCM which is easier to log data and in the end tune.

For reference the stock injectors are 19# and along with the tiny cam are a pretty anemic combo. I don't think that they're suited for racing but I do think that a fair amount of reliable power can be coaxed out of these engines.

I agree. There was a guy on full size Chevy (before I found out about this place) about 10-12 years ago who was able to get 550hp/tq+ with a cam swap, head and intake work, roller rockers, and injectors if I remember right. One of the other weaker parts of the L21/29 is in stock from the intake doesn’t flow the best especially for power above about 4500 rpms.

[skymangs]

so bigger cam and injectors. I think I'll change springs and go aftermarket cam. how about if I went with a 4bbl intake and and like a holly sniper?

['63GENIII]

Originally Posted by skymangs

so bigger cam and injectors. I think I'll change springs and go aftermarket cam. how about if I went with a 4bbl intake and and like a holly sniper?

There's been a few that have done that as well. Like 57Taskforce said, the intake makes great bottom end but not so much (from what I've heard) up top. The heads aren't really set up for it either with the intake ski jump.

I've often thought about switching over to an AM port inj intake to retain the FI but I kinda ran outta steam toward the end of the build so I didn't take it much farther. Plus I've already got too many non running "one day" projects and I'd like to stay married if I could. 😆

Information is a little difficult to find but it IS out there with a little digging.

[skymangs]

so how about something like this? wait, you said the stock intake makes great bottom end torque? I want this for towing, so...