GM 366 Tall Block Information

[Noface]

I've got a line on one of these motors. Late model, but not sure exactly what year.

I intened to put this motor in a '78 3/4 ton 4x4 chassis with a TH400 and NP205 behind it.

I know it's *almost* like a regular BBC, but what I need to know are main differences, like what parts are common, and what parts are specific to this beast.

Also, do you think this might be a good engine for a good 4x4 play truck, and perhaps towing a 5k lb Travel Trailer?

Thanks!

[DarylB]

Save yourself some time (and weight) Go with a 350 small block. You'll have more power/torque and 200lbs less weight on the front axle, in addition to being a cheaper alternative for what you're going to do. If you must have a big block, a 454 would be a more practical option.

The main difference in the tall-deck bigblocks is they have 4 sets of rings and a taller piston (Tall deck 366/427). The intake on those motors are very tall. You might even run into hood clearnence issues as these engines were run in the C50-60 series trucks which had very tall engine bays and raised hoods.

[Quack_Addict]

Tall deck engines pretty much equal NO interchangeable parts with standard SBC's and BBC's.

As already mentioned, go with a 350 or big block. My `84 K20 has a moderately built 355 (350 + .030") that will bounce my girlfriend's head off the back window when I give the skinny pedal a little 'love' (I still catch hell for that... and it happened over 2 years ago!).

Pass on the 366 tall deck. A good DEPENDABLE SBC gasser can be bought or built pretty cheap that will fit the bill for both playing and hauling. If you want to build one up on your own, I can give you the specs from my engine for reference.

You've already got a TH400/NP205 - that's an excellent (and highly desirable) transmission and transfer case combo for your intentions.

[Noface]

Thanks for the thoughts guys.

I've got a tired 350 4-bolt that I was gonna trade for the 366, but after evaluating your reply's, and a few others from guys I know, I think I'll let my buddy keep the 366.

I didn't know to much about them, but thought it'd be cool to have something a little unique. Not many guys running around can say they got a dump truck motor in their 4x4... LOL. Now I understand more why there aren't more of em running around.

Thanks a bunch!

Quack, if you want to ping me w/the setup you used on your 350, that would be cool.

The tranny and transfer case are already done and ready to go, so now I gotta get to work on the motor.

Jody S.

[mhagie]

Around here the favorite combo for towing with the older gassers is a blueprinted 383 smallblock,400's make good power but overheat.
The farmers towing livestock trailers say thats the next best thing to a diesel,a modified big block makes a bunch of power but won't pass a gas station without stopping.
Merle

[Quack_Addict]

My intentions when I built the engine were good HP and torque with a broad power band for playing in the mud and medium towing / hauling - with good street manners

[rjschoolcraft]

Quack,

That sounds a lot like the 350 I built for my 67 C10 and plan to build for my 72 K10.

I used 3927186 (a.k.a. 186) double hump heads (with bolt holes in the ends, the revised, later model casting) These have 64 cc chambers (IIRC). I also use a Holley 600 on an Edelbrock performer intake. That engine is very powerful, but when towing, it can't pass up a gas station. I used to tow the trailer in my signature with it...I got between 3 and 5 mpg. Running solo, the truck will make 14 mpg, but as soon as you put a load behind it and get into the secondarys...

The Holley was jetted too rich as well. IIRC, it came with 62's and I wound up with 57's after running with the vacuum gage hooked up for months. I towed out to the Grand Canyon with it once. In New Mexico, I had to go to 54's (smaller jets) because it was loading up at altitude. Switched back to the 57's on the way back in Nebraska.

I have two practically identical engines. The one in the 67 is four-bolt main, forged crank, 186 heads, etc. The one on the shelf for the 72 is the same, but has nodular iron main caps. Both came out of early 1970 C55 trucks from a local fisheries run by a friend of my dad's.

That engine, as I said, is strong, but I prefer my 6.5 for towing now, even when it was stock. The 350 did better at highway speed compared to the stock 6.5, but the 6.5 did better at elevation (turbo power!). With the mods that I had in place before this rebuild project, the 350 couldn't touch my 6.5 when towing.

By the way, we've got one of those 366's in a 1969 C55 dump truck. It runs pretty well.

[ 04-29-2005, 07:48 AM: Message edited by: ronniejoe ]