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I Need Some 8.1 Spec.'s

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Old 10-29-2004, 11:27 AM
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This is part of the reason (besides fuel economy) that I sold my 2002 HD with the 8.1. I loved it and miss it dearly. But there was literally minimal aftermarket support for it which is odd that no one jumped on the new BBC. Part of the reason is the success of the D-Max and that the majority of HD trucks come either 6.0L or the upgrade D-Max. I know we ordered 5 D-Max's to 1 8.1. The only strong market for it was in marine or power generation circles. Also factor in that the BBC may be going the way of the previous gen SBC in a few years due to ever stringent emissions requirements and the General's development of a competitive V-10.

A plethora of heads and cam options and even a few stroker kits would've turned this thing into an absolute gorilla. The thing had a low compression ratio so S/C'ing is a huge possibility or couple 496 cubes with big bumps in compression and you'd have huge gains.

Problem was....Cost! Then we won't even get into MPG's.
Old 10-29-2004, 11:48 AM
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I would love to have a stroker kit for the 8.1. But that might be wishfull thinking unless I search around marine parts long enough.

With this thing, I'm not worried about mileage. Just seeing what kind of power I can pull from it and the times my car could run.
Old 10-29-2004, 12:01 PM
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If the 8.1 uses traditional SBC mounts, could you use the 4.3 V-6 mounts to put the 8.1 into a 1500-series truck?
Old 10-29-2004, 01:10 PM
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Originally Posted by CMNTMXR57

A plethora of heads and cam options and even a few stroker kits would've turned this thing into an absolute gorilla. The thing had a low compression ratio so S/C'ing is a huge possibility or couple 496 cubes with big bumps in compression and you'd have huge gains.
Mercruiser uses the 496 in several engine packages. the most common is the 496 HO which is 375hp I believe. many folks have tried supercharging them in boats. the problem is breaking pistons. the top ring land is too close to the top of the piston. anything over 6psi and they begin to break pistons. there is a ton of aftermarket stuff for the engine in the marine world and I would assume the parts would be interchangeable but not necessarily street legal.
Old 10-29-2004, 01:37 PM
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Raylar is working on strokers, that what mine will be but 8.1's definately have a piston problem that what happen to my truck. It did make it 2 years on 200HP shot of N2O.
Old 10-30-2004, 09:19 PM
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Lots of mods out there for the 8.1, rayalr makes some good aluminum heads that really give it some kick, theres lots of other small things you can do, but I recommend if you supercharge it you go with a kenne bell over the whipple.
Old 10-31-2004, 03:12 AM
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The main thing I want is a cure for the pistons falling apart.
Old 11-03-2004, 11:29 PM
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Default 8100 currently in my 1967 short bed pickup

I installed a warranty pull motor in my 67 SWB pickup back in July with a DIY fuel injection called Megasquirt. I didnt get the ECM, harness or fuel rail/injector assembly so it was much cheaper and I have the know how.

i used the megasquirt system, www.megasquirt.info
very cheap and i didnt think it was hard to learn. you buil the computer yourself and the harness. uses all GM sensors, very handy


i installed the 8100 with no problems at all
every bolt in the motor is metric, M10x1.5 for most everything, bellhousing, motor mounts, etc, m8x1.0 for the exhaust an so on.

stock big block hedders bolted up to the motor, as well as stock motor mounts for my 1967 pickup. I mated it with a 1968 Turbo 400 transmission and the stock 8100 flex plate bolted up to it fine! i even used a starter for a 1980 small block chevy, $35.00 at autozone!!

everything is the same demensions inside the engine. my inital install the motor was stock, and this past two weeks i pulled the engine and Installed a ZZ502 camshaft (224/234@50, 544x527 lift)from gmpartsdirect.com, $160 shipped and converted to adjustable valve train with some arp studs and harland sharp rockers.

yes the firing order is different on a 8100, and yes the zz502 uses the classic firing order, no problems, my 8100 just runs on 1-8-4-3-6-5-7-2 now with no problems.

i'm using a wasted spark ignitino system instead of coil near plug, usinga 1990 lincoln towncar EDIS-8 ignition moule, and GM DIS coil packs. the EDIS-8 moule uses a 36 tooth wheel and a VR crank sensor. I moutned the 36 tooth wheel to the backside of my harmonic ballancer, and made a bracket that attached to the timing cover bolts. all timing and fuel are controled with a laptop running free software and everything is one in real time, no reprogramming..its on the fly.

check out my website for some pictures.

email or reply with questions. trying to get word out on megasquirt. next project is a 6.0L in my 1962 Impala SS, or possilby a LS1
Old 11-04-2004, 07:49 AM
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So, basically, externally, it's the same as a traditional BBC? And I'd be able to use older BBC swap headers in my 3rd gen as well? I thought the flanges were different too.

I have a friend that's using a Megasquirt on his Probe and he seems to be happy with it. Except for getting his A/F ratio worked out. But I think that's been fixed now.

I thought the crank would be different too since the firing order was changed? Guess not lol.

Consider your website bookmarked lol. I'll get in touch with you when I get started buying my parts.

Thanks for the details!
Old 11-04-2004, 05:49 PM
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The header flange are the same but it's a tall deck block 10.200'' same as a 572cid crate engine. This will make the head abit wider.


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