1978 C20 5.3 swap

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.

Ol_Red_1983

Ol_Red_1983

Junior Member
Joined
Jan 23, 2024
Posts
16
Reaction score
40
Location
Drummond Wisconsin
First Name
Jim
Truck Year
1983
Truck Model
K20
Engine Size
350
Going the 5.3 swap route on my newest project. 1978 Chevy C20. What are you guys using for exhaust? Truck will have an auto in it. Either the th400 that's currently in it or an 80E.
 
Jrgunn5150

Jrgunn5150

Questionable methods
Joined
Jan 11, 2016
Posts
3,126
Reaction score
2,643
Location
Ionia Mi
First Name
J.R.
Truck Year
1979
Truck Model
C10
Engine Size
6.slow
With Speed Engineering long tubes, the remainder of the exhaust is a perfectly straight shot to the axle if you're using one of the aftermarket dual hump crossmembers.
 
TotalyHucked

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
6,946
Reaction score
25,631
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
Here's my original setup when I did my truck. 5.3 with flat top pistons, 799 heads, ~10.2:1 compression, TBSS intake/90mm TB, BTR stage 4 V2 truck cam, Speed Engineering 1 3/4" headers into 2.5" pipe, X right at the front u-joint, Borla ProXS mufflers and out the rear corners. Had a cool/unique sound but eventually the mufflers got to where they wore in and droned really bad.

You must be registered for see images attach


xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media
 
Last edited:
TotalyHucked

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
6,946
Reaction score
25,631
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
Then I swapped in a T56 and a rowdier cam, so I wanted a rowdier exhaust. Same 1 3/4 Speed Engineering headers, stayed with 2.5" piping with the X at the front U-joint but went with the small Corsa Pro universal mufflers (some people call them the Extremes) mounted behind the axle. This setup is LOUDDDD but it's silent in the cab at cruise, it's awesome

You must be registered for see images attach


You must be registered for see images attach


xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media
 
Ol_Red_1983

Ol_Red_1983

Junior Member
Joined
Jan 23, 2024
Posts
16
Reaction score
40
Location
Drummond Wisconsin
First Name
Jim
Truck Year
1983
Truck Model
K20
Engine Size
350
That sounds really good with that cam and exhaust. Will it make any difference with headers from C10 half ton to 3/4 ton C20? Sbc stuff it really doesn't just not sure with LS based stuff of it will.
 
TotalyHucked

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
6,946
Reaction score
25,631
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
Ol_Red_1983 said:
That sounds really good with that cam and exhaust. Will it make any difference with headers from C10 half ton to 3/4 ton C20? Sbc stuff it really doesn't just not sure with LS based stuff of it will.
Click to expand...
No, truck itself has no bearing on exhaust sound. It's all in the engine, header/manifold style, pipe sizing and routing, cross pipe style (or lack of) and muffler choice
 
Ol_Red_1983

Ol_Red_1983

Junior Member
Joined
Jan 23, 2024
Posts
16
Reaction score
40
Location
Drummond Wisconsin
First Name
Jim
Truck Year
1983
Truck Model
K20
Engine Size
350
TotalyHucked said:
No, truck itself has no bearing on exhaust sound. It's all in the engine, header/manifold style, pipe sizing and routing, cross pipe style (or lack of) and muffler choice
Click to expand...
As far as header fitment, does it matter at all from c10 to c20?
 
TotalyHucked

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
6,946
Reaction score
25,631
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
Ol_Red_1983 said:
As far as header fitment, does it matter at all from c10 to c20?
Click to expand...
Not for an LS, the speed engineering headers fit them all well. The only things that come into play is either the ears on the 4L80E bellhousing (you just trim those off) or if you're keeping a factory stick shift with a Z-bar, that can get in the way
 
Ol_Red_1983

Ol_Red_1983

Junior Member
Joined
Jan 23, 2024
Posts
16
Reaction score
40
Location
Drummond Wisconsin
First Name
Jim
Truck Year
1983
Truck Model
K20
Engine Size
350
TotalyHucked said:
Not for an LS, the speed engineering headers fit them all well. The only things that come into play is either the ears on the 4L80E bellhousing (you just trim those off) or if you're keeping a factory stick shift with a Z-bar, that can get in the way
Click to expand...
I really appreciate you answering my questions. Thank you
 
G

goldpack

Full Access Member
Joined
Jul 8, 2025
Posts
533
Reaction score
1,055
Location
Adirondacks, NY
First Name
Donnie
Truck Year
1986
Truck Model
GMC C2500 Camper Spec.
Engine Size
350 with 350 3 speed
in Wisconsin I would hope you can get a whole rusted frame 5.3 truck or SUV.
so like a plow pickup with a snapped frame, or a tahoe / suburban being held together by its upper body work. running great, but ready to be parted into something...and saving from the crusher.

(and then rob off any good goodies that maybe on it at this point,....things that might still be great and needed to make your 300hp project functional, while maintaining your priceless sanity.).

locally on craigslist I can find lots of $1200 things like that (2000-2006 era vins with a T,
and Vins with a Z for flex fuel ideals).
 
P

peats

Full Access Member
Joined
Dec 2, 2016
Posts
390
Reaction score
413
Location
Pennsylvania
First Name
john
Truck Year
72k5, 81c10 short step, 83k10 short fleet, 03 SSR. 25 chevy doodlebug
Truck Model
k5 c10 k10 SSR doodlebug
Engine Size
406 360 6.2 5.3 171
Unless you have drone issues, that x or h pipe is worth about 5 hp. not worth it in my world.
 
You must log in or register to reply here.

Similar threads

D
1978 C20 Belt diagram 454 with AC
Replies
1
Views
379
Goldie Driver
Goldie Driver
D
Fuel gauge and wiring diagram for 1978 Suburban C20
Replies
3
Views
780
dogfart
D
Old Guy Bill
1978 K20
Replies
5
Views
927
78C10BigTen
78C10BigTen
I
SOLD: Selling my project C20
2
Replies
18
Views
2K
goldpack
G
N
L31 vs TBI 454 Swap
2
Replies
15
Views
1K
Scruffy49
S

Latest posts

Forum statistics

Threads
48,413
Posts
1,066,780
Members
42,792
Latest member
WyldTinker
Top