|10-16-2014 10:03 AM|
So full of fail, the tall deck 366 and tall deck 427 were available in medium duty trucks until 1998.
It was replacfed by the medium duty L21 Vortec 454 with 8 coild packs, electronic throttle control and dual 80 pin 512 kb PCM. Its a Vortec 454 with a 24x reluctor. Electronically it thinks its a Vette LS1.
The L21 was available from 1998-2000 for teh most part, it was the 1st GM engine to get 8 coils and ETC. Not to be confused with the 1996-2000 Vortec 454 rpo L29 which came in 3/4 ton and 1 ton GMT 400 style trucks. It uses the 4 x reluctor ,"black box" PCM's, and Vortec style flat crab distributer/cam position sensor combo.
The L21 cam in heavier medium duty motorhomes and cab and chassis etc.
1998–2001 Chevrolet Kodiak/GMC TopKick/Isuzu H-Series 4500 5500
1998–1999 Chevrolet Suburban 2500/GMC Suburban 2500 (option)
1998–2000 Chevrolet Express 3/4 or 1 ton
1998–2001 P12 HD Motorhome Chassis. The Workhorse W-20 is a clone of the P12 Chassis
L21/29 share roller cams, intakes, injectors the L21 got sodium filled exhaust valves and other changes for CNG/LPG sustained WOT usage.
The GEN 7 8.1 came next in line for 2001.
|10-14-2014 11:02 AM|
|vinniekq2||welcome to the forum roller. not worth bringing up old threads like this,,,, start your own? what do you have for wheels?|
|10-14-2014 09:02 AM|
|Roller||Holy thread resurrection Batman......so full of fail I had to.|
|08-13-2012 08:20 PM|
|rogernorton84||ok bro iv got the same engine in a camaro one bad mother this is what to do about the square intake 'buy a square type of spacers one set of square port gasket and one set of large oval small tube of black gasket maker now put the oval on then a small layer of gasket then the spacers and finally the square gasket tightendown the intake run intill engine get warm retighten the bolts from center out ward remember u can put square on oval but not oval on square dont let anyone put down your 366 because iv won a camaro and a mustang and mine just has a points dis and a cam Qjet that spins threw 4th with 22 slicks good luck|
|01-22-2012 06:07 AM|
|peetyweet||thanks pontiac.....I spent countless hours & about $500 to get this motor ready to run & then when I found out that the adjustable distributor was $400 I decided to go in a different direction. I still have the block & may use it in a different application later down the line.|
|01-21-2012 07:01 PM|
|61pontiac2dr||I built up a 366 tall deck and ran great . You will have to change cam and water pump.To use square port intake ,either buy square port heads or oval port intake to go with your heads. I also had a machine shop machine the collar off an hei dist, and made a adjustable collar.Everything else is the same as 396 or 427.,except pistons they have 3 compression rings and compression is I think 8.5.|
|12-31-2011 01:04 PM|
|peetyweet||hold back.....you have a ton of knowledge & I appreciate you blessing me w/ it.....but I am 100% positive that this is a 6.0 366 & it doesnt have the coil packs. Wish you were in the Atlanta area so you could help me out in person b/c it sounds like you have ton of knowledge that could help me on this & other projects.|
|12-31-2011 11:02 AM|
If you're not trolling, then you're at least confusing 2 different engine families.
In the late '60s, GM introduced a tall-deck 366 truck block engine for MDTs. It may well have had domed pistons.
In '99 GM introduced the 6.0L LQ4, based on the then-new LS1. But it was never TBI, and it never had domed pistons. It did have 8 coils.
The 6.0L is 364 cubic inches, not 366. In the automotive world, is is extremely critical to get every number exactly precise, or you create the problems seen in this thread.
ALL 364s have 8 coils. 4 on each valve cover. This is sometimes called having a pair of coil packs.
There are NO exceptions to what I've typed about the modern 6.0L, I'm very clear on every detail of it.
Trying to swap the modern 6.0L into your '93 dually would make for powerful results, but is a very costly proposal, with lots of hassles. If you can't afford a $800 454, which you say is your local asking price, then you sure can't afford to do this swap and get it running. I know, I've done several of my own, including buying used detail items and fabricating my own wiring harnesses.
The old 366 would be easier and cheaper than the modern 364, though the 364 would fit better.
Go figure out what you have. If it is a modern 364, sell it and buy a 350 or a 454. If it's an old 366, it's scrap metal at best.
|12-31-2011 10:18 AM|
Matt....this isn't the Ls1 motor w/ the coil packs....I only refer to it as an LS1 motor b/c that's how summit labels it when trying to find parts for it.
Holdback....I've done extensive research & I'm 99.999% positive that this is a 366. I ran the vin w/ a local chevy parts department & thats what it brings up....Its a 6.0 liter 366 ci motor. I tried running the #'s on the block but couldn't pull any info on it.....the 2nd & last # are blurry....its 13237298...but the 3 could be an 8 & the 8 could be a 3. Tried running diff combo's but still nuthing. And I'm 100% positive it has dome pistons. Tried taking pics but they came out too dark. As a matter of fact, Chevy still makes a 366 cubic inch engine (w/ coil packs) w/ 360 hp. They come in some of the new 2011 2500 HD trucks w/ allisson transmissions.
|12-31-2011 08:59 AM|
I'm 99% sure the 366 was long gone by '98, and I'm not convinced you know exactly what you got your hands on.
It doesn't take more than a 350 to make full use of the capabilities of a dually pickup, you'll just be going a little slower when towing a maximum load.
Doing a 350 install will be far cheaper and far easier, and will give more real torque, and better gas mileage, than that 366.
|12-31-2011 08:55 AM|
talk about changing horses in the middle of the stream--ls1?
you need to do MORE homework before you spend another nickle
|12-31-2011 08:41 AM|
|peetyweet||More good info hold back.....let me add a few things to the equation to see if makes a difference. The 366 that I have is a LS1 motor out of a 98 c-60 & was a throttle body engine. It has decent stock heads (not great) & dome pistons that provide 9:4:1 compression. Btw, this isn't my 1st choice of engines to drop in my truck....as a matter of fact its not my 2nd or 3rd choice either but again, I got it on trade for next to nothing & I'm trying to make it work as inexpensive as I can. I've had the intake for sale on craigslist for at least a month & no interest. I live in GA & I'm familiar w/ pick & pull so Imma prob check them out to see if they have a 454. But, I'm probably still gonna try to make this engine work for the time being.|
|12-31-2011 08:19 AM|
As for a 454, go to Pick-N-Pull, or your local equivalent. I've found them from Norcross, Georgia to southern California, so they're pretty much everywhere.
You use their hoist, you do the labor yourself, you remove what you need from the car (or pickup)
Any 75-'89 454 from a 3/4-ton or 1-ton pickup would be a great choice, but before pulling it, pop the valve covers and intake manifold to check for any issues. Once it's out, pop the pan and check thoroughly before going any farther. You'd be mad if you got it home then found a spun bearing, right?
Plan on investing $50 in a full set of new gaskets, and replacing every gasket in the engine.
The 366 really doesn't work. The large oval ports are just too large for 46 cubes per cylinder to create any port velocity. Peanut-port heads would help, except then you'd have maybe 7:1 compression at best, and noone makes peanut-port spacers to put these heads on tall-deck blocks.
You'd be seriously better off with virtually any 350 than with that 366. They're long gone for good reason. Plus the 366 heads never had hardened exhaust seats, AFAIK, so you're gonna have costly problems there, now or very soon.
|12-31-2011 07:57 AM|
|peetyweet||Hold back.....some good info but where can I find a 454 for $200?? Everywhere I look people are asking $800 or better. And I'm using the 366 b/c I was able to trade for it & after doing a fair amount of research, I found that this 366 comes stock w/ 300 hp & 360 lbs of torque. I figure w/ a decent intake, headers, & 750 carb, I could easily increase those #'s to 350 hp & 400 lbs of torque....which is more than enought for the work that it will be doing.|
|12-31-2011 07:47 AM|
i kinda agree with some of whyholdbacks' post
a 454 would be a lot better choice unless you want build this 366 because its different
but if you have done ANY home work at all, you know that already
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