dmc454

I think your idea is a cool one.I have been looking into this for 2 1/2 years now.Just not in a position to act now.The things I considered are GM used these and are still using them for boats & the stresses they are under are tremendous.WOT for a long time putting the crank under a hell of alot of abuse.If they can live in a boat ,they can live in car.If you can find them look for the HP3 heads for the 525 HO MAG engine.They were CNC ported .Dont know flow# .Just never seen any info from anyone that flowed these.Look for a 525 HO MAG cam.You can get the cam from a large boat dealer.I have seen these items on EBAY before.The boat motor package made 525HP dont know torque# but im shure its close to HP.I am going with upgraded valve train and pistons.Im going to use a megasquirt system to fire the thing.I know that everyone would say stick with the older big blocks but I like to be different and challenge myself to make things work. Good luck to you and I would like to see your work when its done.When I can get to my project its going into a 1969 Chevy Kingswood wagon.

Vicious95Z28

iTrader: (1)

I'm pretty sure that the H.O Marine 8100 has a forged crank. Typical production 8100's did not.

TieRod

The early ones did but GM found the iron crank to be sufficient.

andrew, I'm not sure what happen. When I stepped out of the truck oil was on the ground burning. By the time the fire was extinguished. There wasn't much left. Good thing is the turbo and engine came out fine.

3rdgentug

iTrader: (23)

tierod that was a sweet truck
sry bro

hannes_slanec

I would also prefer to build up a new engine before I rebuild an old engine with 60´design and technic.

GM spend 100 000 of dollars and hours as well to create that hi tech engine with cam trigger, EFI ect,ect...

Many things of the old BBC fits exept of the heads and intake and unfortunatly are the only company who is building alu-heads for that engine (www.raylarengine.com) unreasonable expensive. But building an old BBC with EFI and all that hi end stuff would cost you a fortune.

Thats my opinion.

Hannes

lsxyj

iTrader: (1)

i love my 8.1 in my hd would love to put one in my c10 a vortec 454 will have to do for now

hannes_slanec

I still love the Vortec 8100 with its advanced EFI system but I have bought also an Mark IV BBC not because I estimate them as a better choice but I really cannot afford to modify the
496.
Fu---ing Raylar ask for 3000 for alu heads, 800 for a forged crank and 1300 for forged pistons and rods.

Only that few parts are already 5000$ and I have bought a rebuilt, sleeved, blueprinted and +-1gramm computerbalanced 540cid stroker with all forged internals 3200$.

I is only a short block but alu heads for that engine are cheap to get.

I keep my 496 and will see if there are parts available in the future.


You have the Vortec 7400 you say?
I have get offered a EFI of that engine and would like to build it on the 540cid, will the
intake ports fit to mark IV heads.

Deos it also have a cam and crank sensor and do you think I could complete it with a crank trigger and 8 single coils like the Vortec8100 is using it?


Thanks Hannes

Awake455

For the record, the 8.1 is still being made, only not in pickups. Look at the medium duty trucks and boats, they can still be found in decent numbers there.

The last vortec 7400, the one used in 2000 medium duty trucks, was a coil-near-plug engine with drive-by-wire. It had the exact same intake...P/Ns and everything... as the L29 454 that was in the 96-99(?) pickups. A cable operated throttle body swapped right over in place of the electronic unit. It had a funky distributor looking thing that went where the actual distributor went...identified as a cam position sensor. A crank sensor was on the front of the engine in the timing cover. The pigtail leading from it can be seen leading up to the front right corner of the intake.



Note the front coil was removed in this pic as it was cracked during shipping. This was without a doubt the last and most technologically advanced 454 that GM ever made.

1BadAction

iTrader: (10)

there is a good number of these 8.1s running around in very high HP boats and not to mention, the medium duty trucks. theres ALOT of potential here, but until more people start using them, cost will be an issue.

hannes_slanec

I see, than it is not that one:

http://cgi.ebay.com/ebaymotors/ws/eB...MEWA:IT&ih=009

Better I look for a newer one, right.
I love the coil near plug systems and want to use them with my 540cid engine.

If somebody can recommend me a junkyard where I could find something like that please tell me.


Thanks Hannes

Awake455

Hmmm.... all on 87 octane---9.1:1 compression
2008 Vortec 8100 medium duty truck engine (L18)
325 hp @ 4000 rpm
450 lb-ft @ 2800 rpm

Vortec 8100 marine engine
392 hp @ 4600 rpm
503 lb-ft @ 3200 rpm
Mercruiser's 496 MAG MPI carries 375 hp

Vortec HP 8100 marine engine
419 hp @ 5000 rpm
503 lb-ft @ 4000 rpm
Mercruiser's 496 MAG HO MPI carries 425 hp

Vortec 8100 HP3 marine engine
525 hp @ 5200 rpm
560 lb-ft @ 4000 rpm


Methinks there is a lot of power to be had in the OE aluminum intake/ iron heads used on the 8.1L.

hannes_slanec

Funny I did not see the picture of your engine before, but now when I saw it I know
T H A T I S T H E E F I S E T U P I W A N T

Did not really understand what you meant with the last posting.
If you meant that I could go with the new Vortec 8100 engine, forget it.

I love that engine and have a shortblock but the heads are totally different and the plenum will absolute not match the the mark IV heads elsewise I would have never bought the mark IV block.

I have got a offer (write about the same topic at that moment in hotrodders bulletin forum) for a Vortec 7400 plenum and think about only to use the plenum and the rest of the EFI could come from the Vortec 8100, a ECM I have already.

What do you think?

Hannes

65chevelle''ss''

Brand new member here... First post!

I joined here because I saw this thread on the 8.1. Lots of good information here guys! I became interested in the 8.1 a few years back not unlike alot of you. The plan is to put it in my Pro-touring '65 Chevelle . Here is basically what I have so far:

HEADS

-Exhaust ported and bowls cleaned up
-Went from stock 1.74 exhaust valves to Manley 1.88 stainless
-2.19 intake

BLOCK

-Decked
-Line bored (.030)
-Balanced
-Eagle rods
-Stock 4 3/8'' crank
-BHJ balancer
-JE pistons (9:1)
-Comp Cams hydraulic roller w/560's lift

For the engine management I've got the FAST setup. I plan on running a custom Hogans intake however I have not bought this yet. Here's a few pics

hannes_slanec

That is how it is supposed to be! I have contact with a guy to that topic and we are just about to find out how to modify the block to use Mark IV aftermarket heads like GM did it at
its Coolside II project.
It is possible with some small modifications, if you are interested tell me and I send you pics.

Thanks Hannes

65chevelle''ss''

Heck ya, send the pics my way Hannes!!! I'm interested in any info for the 8.1 Thanks!

hannes_slanec

I will send you the pics and the text of the guy who compared the parts to find any possible
interchangeability.
Also a lot of old BBC parts fit to the gen VII Vortec engine as you know probably. If you dont have old bbc parts in your garage to compare tell me and you get a list what parts I know.

Do you have the EFI? I not you can use older heads (with modifications and use a tall deck intake or a usual with spacers)

I know how you feel, I made the same voyage as you and subscribed in 10 different Forums to find people to help me on that engine. But actually most of the time nobody came in my threads to help me.


Hannes.

65chevelle''ss''

Yes, I have all the stock EFI stuff and I do intend on staying with the EFI. I won't be running the stock intake manifold as I said before, I'm going with a Hogans instead. I already have the FAST engine management system and most all other parts to put this thing together and run it

That would be cool if you could put a list together for me Hannes of all the BBC interchanges that you know of. It could be very helpful! Thanks for all your help. Should be a fun project!!
T

bbeck

hey tierod, when did they stop using the forged cranks in these motors? Does anyone know an easy way to tell if the motor would have a forged crank? I will probably be going to look at a couple of these motors this next week. Both of them are 2001, I believe. So Hannes, older gen BBC heads can be used on these motors? Would you post a link to this info or post the info on here so we can all see it? I would like to see approx 500 whp.

dietzster

I'm also intrested in a list of bbc interchanges. What mods are needed to put older style 454 heads on an 8.1 block. This is the first forum that said it can be done. If you have other great 8.1 links I'm intrested in those too. I'm thinking about putting an 8.1 in my 98 k3500, but I want to keep the vortec factory 454 fuel injection by putting on factory 454 heads so it looks stock. Any body seen this done yet?

hannes_slanec

Not the forum says it fits, its me as I put light-years of time in that research.

I see no problem to swap the plenum although the plugs of the harness should plug right in the Vortec 496 plenum.

If you go along with the Vortec 454 plenum consider to buy intake spacers to compensate the space between the heads as the Vortec 496 is a 10.200" tall deck engine. That is the reason of the displacement, the bore is still a 454 diameter.

Will send facts to the heads later, but I tell you modifications are need to be done albeit
it will pay as alu heads dont need to be bought from Raylar Engines (3000$).

Hannes