350 to 366 swap in a 75 C 30, How much of a PIA?

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
943
Reaction score
1,326
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
What year is the C50? 1967 should be the last year of the 420. We have a '67 C50 with the 420 and a '68 C50 with a 5 speed.
Do not know what year it is, didn't look. Will be back by there in a few days will check all that out.
That C50 may be running the SM420, it too has the provision for the PTO. If it has a bulge on the passenger side it's a 420.
Never heard of a 420, trans anyway, sure it would run a different pto than a 465? As all this has come around I remembered another early 60's bob tail, and it's still there, good chance it will become the tender trailer. One Ive been speaking about may just stay in the fence row a while. Depending on what he wants for it, it may be his or my fence row.
 

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
943
Reaction score
1,326
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
Wrong.

No problem buying distributor or an aftermarket intake for the peanut port tall deck engine. The new intake will work with most aftermarket heads out of the box
There are kits that are spacers that allow a standard deck intake to be used, (spacers/gaskets).
This Dart intake requires a slight bit of machining for stock heads.
You can get an aftermarket intake that is cast with a "low hole" for the stock standard height distributor or a longer one that drops right in the tall deck location.
This application done with a Dart AirGap intake.

https://www.summitracing.com/parts/CRT-M4530 is the fuel pump used.

You must be registered for see images attach
Ok, been an interesting tread.
If i may, in this picture we are looking at a tall deck big block in the engine compartment of a square body correct? How much of a pain was it to get in there? More than matching up motor mounts? Have to move any sheet metal? Is there any room left to work on the darn thing after it's in there? Etc...etc..?
On a different note, You running 2 altenators? or what am I seeing?
 

Grumpy

Full Access Member
Joined
Jul 22, 2021
Posts
169
Reaction score
396
Location
Saskatchewan
First Name
Daryl
Truck Year
1985
Truck Model
C10
Engine Size
350
The 366 is horrible as an engine! No power and the innate ability to never drive past a gas station for any reason. The cylinder bores were never meant to be machined more than +0.060" and the thought of stroking one is diving into money wasted.
While the Mark IV Series includes the 366, 396, 402, 427 and 454, the truck blocks are all taller decks, their heads are all the squeamish little round ports and the crankshafts will require extensive machining to balance if they are used in a regular deck block. What is realistically transferrable? Bolts, oil pan, rocker covers, water pump and pulleys.

Your C30 would be better off with a mild 383 build. Cheaper to build up, easier to maintain and parts are readily available in most cases.
If you want a big block, a decent 454 with a few basic upgrades will keep you happy.
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
305
Reaction score
691
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
Ok, been an interesting tread.
If i may, in this picture we are looking at a tall deck big block in the engine compartment of a square body correct? How much of a pain was it to get in there? More than matching up motor mounts? Have to move any sheet metal? Is there any room left to work on the darn thing after it's in there? Etc...etc..?
On a different note, You running 2 alternators? or what am I seeing?
This tall deck is indeed in a 1986 square 4x4. No clearance problems.
I did have to make some brackets for the dual alternators.
Only air cleaner I found that would clear under the hood.
No sheet metal work or the like to install. Truck has 4.56 rears and 35" tires.

Many of the local "milk haulers" have used GM trucks with this engine for years.
One fellow has a 15 truck fleet of quad axle straights. They have plenty of power as a tanker of milk is not fluff.
He said he bought a couple with the 427 but they seemed to have an overheating condition inherent to them.
This engine was from a US Air Force Blue Bird bus.
 

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
943
Reaction score
1,326
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
This tall deck is indeed in a 1986 square 4x4. No clearance problems.
I did have to make some brackets for the dual alternators.
Only air cleaner I found that would clear under the hood.
No sheet metal work or the like to install. Truck has 4.56 rears and 35" tires.

Many of the local "milk haulers" have used GM trucks with this engine for years.
One fellow has a 15 truck fleet of quad axle straights. They have plenty of power as a tanker of milk is not fluff.
He said he bought a couple with the 427 but they seemed to have an overheating condition inherent to them.
This engine was from a US Air Force Blue Bird bus.
Thank You. What engine is it?
 

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
943
Reaction score
1,326
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
366


You must be registered for see images attach
How's it work in the truck? Would you reccomend it for a heavy ass c 30 work truck? Never in a hurry but will pull a 15,000 pound backhoe?
Appreciate it!
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
305
Reaction score
691
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
How's it work in the truck? Would you reccomend it for a heavy ass c 30 work truck? Never in a hurry but will pull a 15,000 pound backhoe?
Appreciate it!
Works fine.
It will pass anything but a gas station but, for a local work truck it does a great job.
Parts are available from GM.
Have not had any problem finding any parts as this engine was in a lot of school buses also.

You must be registered for see images attach
 

CalSgt

Full Access Member
Joined
Oct 3, 2021
Posts
386
Reaction score
499
Location
CA
First Name
Casey
Truck Year
1980
Truck Model
Chevy K-10 Custom Deluxe
Engine Size
350
Can you not stroke and bore the hell out of a tall block? 540 anyone? 496 crank and garbage can pistons?
Thats what I was thinking, i know some of the GM performance crate motors are tall deck BB's including that new ZZ632. I have a 427 tall deck out of a C-60 dump truck I'm tempted to do something with...
 

Latest posts

Forum statistics

Threads
36,195
Posts
764,802
Members
25,352
Latest member
El82Blazer
Top