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tall deck big block info 366, 427

bftank

bftank

1/2 ton status
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this is meant to be an informative thread on an obscure engine. i am by no means an expert, and as you can see by my post count am a bit of a newb so be gentle. had a couple members ask me about them in different posts so i thought i'd start this and see how it went. currently i am running a 366 big block chevy in my 1989 gmc suburban. i have adapted the tbi to work with this motor. it is backed by a 700r4 and np241. best in town mileage has been 11mpg with 3.73 gears and 31x10.5 tires. prior to the suburban i had this in a 74 chevy 1/2 ton backed by sm465, np205 3.73 gears and 36 in swampers. in this configuration it had a 750 edelbrock on it, don't know what it got for mileage. having adapted it to 2 different truck and transmissions has given me some experience. the internet has helped me to glean some specs about these "throw away motors." maybe i/we can answer some swap ? so i end this post asking what questions are out there about these motors? and i will post some pros and cons in a later post. thank you in advance for all input. bftank

c60 366 eng.jpg
 
The 366 is not really worth putting any money into but the 427 TD on the other hand can make some BIG cubes with. There are several differences between these beast and the standard deck BBC. First off the deck is .400" taller which requires a different distributor, takes a different intake OR the use of spacers along with a standard intake, the internal parts that are different and not interchangable are the pushrods, connecting rods, and pistons.
 
were the tall decks 4 bolt as well?
would headers, power accessories, etc need different brackets due to the .400 taller block?
 
Are they internally balanced, or would you be able to use the flywheel off of one on a 454?
 
I believe internal, only 454 were external on BBC
 
I like reading about people doing stuff a little different and not "accepted". So what did prompt you to decide to use a 366?

We had an old boom truck with a freshly rebuilt 366 by the previous owner. We tried selling just the cab & chassis but no one was interested. I always wondered if the motor would have been worthing swapping if only because it was rebuilt and free to me.
 
yeah there cool motors I've parted out a few of the C-60's and kept the motors but I've never done anything with them . So I'm super interested in this thread
 
i used the motor in the truck because it was cheap and a bb. at the time i didn't know any more about them. the 366 and the 427 get there torque from a forged 3.76 stroke crank(mortec.com). with the 366's thick walls (3.935bore) they are a good motor for super charging or turbo charging being able to handle high boost pressure. the 427 has the much more common 4.25 bore shared with the 454. 366 can be stroked but would require custom pistons due to uncommon bore. both have reg. 454 crank and cam journals, and connecting rods measuring 6.135(regular bb rods according to the Scat catalog). both use a reverse rotation cam and have hex shaped oil pump drive. these can be swapped out to regular cam and drive as well as oilpump. this allows you to run a stock 454 or small block distributor with the slot drive oil pump. from what i have researched the heads can be swapped w/o adapter for other 454 style heads, and intake is where the difference is made up in the deck height. you can use a standard bb intake but it would require spacersbetween head and intake, supposedly you can get these from summit. on my truck a 454 water pump fit with no problems as well as power steering pump. the alternator didn't want to match up well with the 454 water pump and holes in the had so we "engineered" a bracket to make it fit. i used cheapo flowtech 454 headers that fit good no clearance problems. mine used a 454 flywheel and has a harmonic balancer, no problems. 76 zimmer, i remember reading somewhere that they were 4 bolt mains but couldn't say for sure. compared to my rv cammed fresh 350 the 366 was a torque monster. if you want to have crazy hp and tq and monster cubes go with the 427 like 4x4 high said, but if you want a good reliable lowend beast for cheap or free get a 366.:D
 
i have a tall deck 366....i was told the crank and rods are factory nitrated, and in a regular 454 block make a 427....say it would be nice in front of my sm465&np205, i recon' if it will pull a huge grain truck w/a standard trans, those 44''s should be no sweat, i wonder what kinda gears in a bobtruck rearend?
 
bftank said:
i used the motor in the truck because it was cheap and a bb. at the time i didn't know any more about them. the 366 and the 427 get there torque from a forged 3.76 stroke crank(mortec.com). with the 366's thick walls (3.935bore) they are a good motor for super charging or turbo charging being able to handle high boost pressure. the 427 has the much more common 4.25 bore shared with the 454. 366 can be stroked but would require custom pistons due to uncommon bore. both have reg. 454 crank and cam journals, and connecting rods measuring 6.135(regular bb rods according to the Scat catalog). both use a reverse rotation cam and have hex shaped oil pump drive. these can be swapped out to regular cam and drive as well as oilpump. this allows you to run a stock 454 or small block distributor with the slot drive oil pump. from what i have researched the heads can be swapped w/o adapter for other 454 style heads, and intake is where the difference is made up in the deck height. you can use a standard bb intake but it would require spacersbetween head and intake, supposedly you can get these from summit. on my truck a 454 water pump fit with no problems as well as power steering pump. the alternator didn't want to match up well with the 454 water pump and holes in the had so we "engineered" a bracket to make it fit. i used cheapo flowtech 454 headers that fit good no clearance problems. mine used a 454 flywheel and has a harmonic balancer, no problems. 76 zimmer, i remember reading somewhere that they were 4 bolt mains but couldn't say for sure. compared to my rv cammed fresh 350 the 366 was a torque monster. if you want to have crazy hp and tq and monster cubes go with the 427 like 4x4 high said, but if you want a good reliable lowend beast for cheap or free get a 366.:D
Click to expand...

ALL BBC EXCEPT for the 454 are internally balanced EVEN the tall deck engines.
 
Buddy got a TD 427 for free a few years back out of an old city bus a friend of his' boss was using as a mobile tool crib. Bolted into his K5 with nothing but the usual BBC swap parts needed to swap a typical 454 in. After he got the fuel supply issues sorted out (truck was a TBI 89 and engine had a big Quadrajet) he did nothing but smile.

Of course, he was also waiting for the 10 bolts and the TH700R4 to blow up...:crazy:

Haven't been in touch in a while so dunno whatever happened to it.
 
the 366 that i have initially had a 4 hole square bore intake on it. it has since been carved into a rough dual plane style intake. when i first got the motor it had 4 restriction tubes in the 4 holes of the squarebore intake. after i pulled those out it was a lot less finicky with the timing and the 750 edelbrock, and way more fun to drive. with the restrictors in there was approx. 1/4 inch between the bottom of the intake and the bottom of the tubes, and ran like a dog. changing out the edelbrock for the tbi took away some torque, i think that's due to the 450 cfm of the tbi and small injectors. i might fiddle w/a spacer, bigger injectors and better regulator this summer see if it gets better power.
 
i've thought about it. heard the wiring was different from the 5.7 tbi. that and i don't want to put too much into it yet. it still runs better than the 5.7 did and after suspension, tires and drivetrain swapping i'm hoping to put in a 4bt cummins:D
 
I am very interested, I live in a rural area with millions of these trucks around, Ive never really thought about them before. My only question is about the regular chevy distributor. When switching to a regular rotation cam, how would that work with the .400" taller deck? wouldnt the distributor be too short?
 
you have to use a Tall deck specific distributor

MSD and mallory make them (and of course stock LOL)
 
actually i ordered my petronix distributor for a 454, it fit fine, good contact. and when i swapped it into the "89 suburban i used the ecm referenced small block distributor off of the 5.7l. the motor still has the stock intake, i the the extra height is only between top of cylinders and the crank not the valley between the heads. otherwise you wouldn't be able to use standard bb intakes w/only spacers between the head and the cylinders.
 
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