292 to 427T industrial swap, in C30. Many questions on fitment.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

AyWoSch Motors

The Parts Guy
Joined
Nov 6, 2020
Posts
4,690
Reaction score
13,695
Location
New Mexico
First Name
Ayden
Truck Year
1986
Truck Model
K1500 Sierra
Engine Size
350ci V8
@Dooley

Youve done this before, right?
I know you weren't a huge fan of it, but im kinda set on wanting to.
Got any info, or big things that were a pain? Got any pics?
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,464
Reaction score
5,631
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
Not only is the BBC clamshell mount different, it actually is supposed to mount in different holes. The SBC mount will work, usually.

The big problem I see is that you didn't get a flywheel with that motor. 427T is internally balanced and will need a specific flywheel different from a 454.
 

AyWoSch Motors

The Parts Guy
Joined
Nov 6, 2020
Posts
4,690
Reaction score
13,695
Location
New Mexico
First Name
Ayden
Truck Year
1986
Truck Model
K1500 Sierra
Engine Size
350ci V8
Not only is the BBC clamshell mount different, it actually is supposed to mount in different holes. The SBC mount will work, usually.

The big problem I see is that you didn't get a flywheel with that motor. 427T is internally balanced and will need a specific flywheel different from a 454.
I did get a flywheel with that engine actually, but im running it with an automatic, so it has a flexplate right now.
 

AyWoSch Motors

The Parts Guy
Joined
Nov 6, 2020
Posts
4,690
Reaction score
13,695
Location
New Mexico
First Name
Ayden
Truck Year
1986
Truck Model
K1500 Sierra
Engine Size
350ci V8
Well its in, sorta. Trans lined up, my new mount lined up, lined up and went on the trans, and is lined up on the mounts. Everything seems to clear all the way around it. Only issue is, its seems the pan is hitting the crossmember a little tiny bit. Gonna pull it again, and see if i can "massage" it a little bit.
You must be registered for see images attach
You must be registered for see images attach
 

Bextreme04

Full Access Member
Joined
May 13, 2019
Posts
4,464
Reaction score
5,631
Location
Oregon
First Name
Eric
Truck Year
1980
Truck Model
K25
Engine Size
350-4bbl
I did get a flywheel with that engine actually, but im running it with an automatic, so it has a flexplate right now.
Hopefully the right flexplate. The same thing holds true on that. A standard 454 flexplate WILL NOT work. I suggest you just go get a normal truck pan for that. Standard Mark IV 454 pan for a square will bolt right up and obviously clear everything just fine
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,639
Reaction score
28,945
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Internal balance big blocks use the same flexplate as a garden variety pre-'86 small block (except the 400). Bolt pattern for torque converter can be different, but many flexplates have two bolt patterns. Elongating 3 holes works too.
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
377
Reaction score
988
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
@Dooley

Youve done this before, right?
I know you weren't a huge fan of it, but im kinda set on wanting to.
Got any info, or big things that were a pain? Got any pics?
Never followed a "6" with a Big Block.
Replaced small block and 6.2/6.5 also.
You will need a hydroboost lower power steering bracket for the big block.
The small block I replaced with a steel crank 454 out of a 2WD Suburban.
I used the motor mounts from the Suburban.
The Big Block T replacement I used the Diesel mounts from the D30.
Hood clearance was close.
No wide problems or at rear of tall deck.
You can get aftermarket intakes for long or short distributors.
I went with short.
This is my go to on the fuel pump for this engine swap.
https://www.summitracing.com/parts/CRT-M4530
 

Attachments

  • Tall deck Big Block 005.jpg
    Tall deck Big Block 005.jpg
    310.2 KB · Views: 66
Last edited:

AyWoSch Motors

The Parts Guy
Joined
Nov 6, 2020
Posts
4,690
Reaction score
13,695
Location
New Mexico
First Name
Ayden
Truck Year
1986
Truck Model
K1500 Sierra
Engine Size
350ci V8
Internal balance big blocks use the same flexplate as a garden variety pre-'86 small block (except the 400). Bolt pattern for torque converter can be different, but many flexplates have two bolt patterns. Elongating 3 holes works too.
Hopefully the right flexplate. The same thing holds true on that. A standard 454 flexplate WILL NOT work. I suggest you just go get a normal truck pan for that. Standard Mark IV 454 pan for a square will bolt right up and obviously clear everything just fine

The flex plate is off a 70s 305 i bought for parts. Its a even 6 bolt pattern, matches my 6 bolt converter perfectly, i test fit it.

The pan looks like its going to be the only issue. Its massive. If it will fit, ill it, but if wont, ill have to change it.
 

AyWoSch Motors

The Parts Guy
Joined
Nov 6, 2020
Posts
4,690
Reaction score
13,695
Location
New Mexico
First Name
Ayden
Truck Year
1986
Truck Model
K1500 Sierra
Engine Size
350ci V8
Never followed a "6" with a Big Block.
Replaced small block and 6.2/6.5 also.
You will need a hydroboost lower power steering bracket for the big block.
The small block I replaced with a steel crank 454 out of a 2WD Suburban.
I used the motor mounts from the Suburban.
The Big Block T replacement I used the Diesel mounts from the D30.
Hood clearance was close.
No wide problems or at rear of tall deck.
You can get aftermarket intakes for long or short distributors.
I went with short.
This is my go to on the fuel pump for this engine swap.
https://www.summitracing.com/parts/CRT-M4530
It has a hydroboost brake/power steering, and matching power steering pump, but bracket is going to be fun to fine.

Im going to leave the stock intake. Seems to be fine, and low enough. Also already had a long shaft HEI that works fine.
Intake is square bore already, so ill just run my AFB and my stubby short eddy air cleaner. Looks like itll work.

Did you have any clearancing issues at the pan? You put yours in a 2wd or a 4wd?

Also did you use a stock intake on either of your builds?
 

Dooley

Full Access Member
Joined
Mar 19, 2014
Posts
377
Reaction score
988
Location
North Coast
First Name
RW
Truck Year
1988
Truck Model
V30
Engine Size
454
It has a hydroboost brake/power steering, and matching power steering pump, but bracket is going to be fun to fine.

Im going to leave the stock intake. Seems to be fine, and low enough. Also already had a long shaft HEI that works fine.
Intake is square bore already, so ill just run my AFB and my stubby short eddy air cleaner. Looks like itll work.

Did you have any clearancing issues at the pan? You put yours in a 2wd or a 4wd?

Also did you use a stock intake on either of your builds?
Both trucks were 30 Series 4X4 with a T400 transmissions.
The only tall deck I used a Dart because the stock one was a double thermostat version and was huge.It allowed me to use a standard water pump.
Since I was changing it I decided to use the short shaft to take the extra room at the rear of the engine.
 

Attachments

  • Tall deck Big Block 001 A.jpg
    Tall deck Big Block 001 A.jpg
    79.6 KB · Views: 76

Ichy62

Junior Member
Joined
Feb 7, 2022
Posts
10
Reaction score
7
Location
Petaluma ca
First Name
Rich
Truck Year
1974
Truck Model
C10
Engine Size
327
I swapped a (low deck) 396 into a 74 shortbed, perhaps ignorant luck, but it dropped right in, had no issues but I had heard in the years since that the true big block frame brackets located the engine slightly forward perhaps. Had no problems with the headers either. The height difference is only .4inch "up and out", so if you are using stock manifolds, fair bet no fit issues there. As far as the accessory drive, the alternator would mount slightly higher as the pivot bolt went into one head front hole so possibly only a bit longer belt there. The "max 4000 rpm" deal may be partly the rpm limiting carb setup they had, but really no need to rev it much more than that. The 427 only has a 3.76 stroke and has a steel crank so no worries there either. There are intake manifold spacers available to install a standard 4 barrel intake if needed. For me it was a fantastic swap that entirely changed the character of the truck, wish I hadnt sold it :-/
 

Attachments

  • Screenshot_20230425_081707_Gallery.jpg
    Screenshot_20230425_081707_Gallery.jpg
    76.7 KB · Views: 62

Craig Nedrow

NADAR UNDER THE RADAR
Joined
Sep 1, 2018
Posts
1,111
Reaction score
2,404
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
How did I miss this!! ! 10.2 tall deck block is Nirvana to me, 4.5 stroke 4.310 bore 525...you lucky dog.
 

Forum statistics

Threads
44,427
Posts
957,691
Members
36,793
Latest member
koolblue84
Top