SOLD Please Take This 305.SOLD

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.

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
Does anyone want a 305 long block? It’s got some accessories, too. It’s in my way, and I don’t want to throw it away. It’d be a good project to get a roller going. It came out of an ‘86 K10, 26K miles since new, was in Hurricane Katrina, was completely rebuilt by a machine shop.

I’d take the heads off and make sure it’s clean and lubed, but it should be good to build. It’s got the 601 heads so decent in the 305 world.

You must be registered for see images attach
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,008
Reaction score
8,977
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
Sure wish I was closer. If it's a runner, I'd sure put in my 86 K5 to at least get it running until I can build this 350 engine I have for it.
 

SquareRoot

Full Access Member
Joined
Mar 18, 2017
Posts
3,659
Reaction score
6,602
Location
Arizona
First Name
Mike
Truck Year
85
Truck Model
K20
Engine Size
350
305's, 400's and pit bulls. They all "sounded good at the time." Lol
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
You must be registered for see images attach
You must be registered for see images attach
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,008
Reaction score
8,977
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
I bet that thing can be made to run again. I've got people checking on ride for it. If someone else needs it and has the means to get it, don't let it go to waste, go get it. I'd just put it in my K5 as a runner for the time being. Hopefully one of the tow bros that goes that way wouldn't mind stopping to pick it up.
 

Colin

Full Access Member
Joined
Mar 12, 2018
Posts
226
Reaction score
228
Location
Covington, GA
First Name
Colin
Truck Year
1978
Truck Model
K10 Silverado
Engine Size
350 cu. in.
No experience with one, but everyone talks about how "gutless" a 305 is.
What can be done, fairly easily, to beef it up some to add some torque in
the lower RPM range, and boost HP a bit.
And, is it worth it?
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
No experience with one, but everyone talks about how "gutless" a 305 is.
What can be done, fairly easily, to beef it up some to add some torque in
the lower RPM range, and boost HP a bit.
And, is it worth it?

I daily drive a stock 305, and it’s not a race car, but it can at least get out of its own way. The 305 is held back by its puny bore, and that’s why people flock to the 350 because it’s a better performance platform. That being said, the same bolt ons and tricks to boost power are universal to SBCs. The 601 truck heads are almost as good as the 416 heads, and both are HO heads by 305 standards. You can port and polish these heads up to 2.02/1.6 valves I’m pretty sure. A cam upgrade helps. I don’t like anything that screws with vacuum too much on a daily or semi-daily driver so something like the Comp 12-300-4 or equivalent seems sufficient. An aluminum intake like the Edelbrock 2101 might help marginally, but it’s so much easier to assemble with the lighter intake. A good ignition system (standard HEI), proper gearing, and a more advanced base timing without making it ping help. Headers and a deletion of the cat and air injection should bring it home. I haven’t tested this out yet, but this hypothetical motor should be around a 300 hp plant. Not bad, but the same investment yields you more in a 350, and they’re pretty ubiquitous. That’s why people shy away from them for the most part. I like the little engine, though. It’s more reliable than I could have ever hoped for, and when it gets tired, I’ll rebuild it, do the aforementioned upgrades, and keep on trucking.
 

TravisB

Full Access Member
Joined
Jan 3, 2018
Posts
1,087
Reaction score
1,071
Location
Kentucky
First Name
Travis
Truck Year
1978
Truck Model
C10
Engine Size
350
There's a guy with a machine shop in town running 11s with a 305. It gets some work done for the little powerplant.

xc_hide_links_from_guests_guests_error_hide_media
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,008
Reaction score
8,977
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
I sent you a PM @1987 GMC Jimmy . One of my tow buds is leaving for NOLA Sunday or Monday and will be there for a week or 2 pull IAA cars then come back to OKC. He said he'd stop in Wesson to pick it up if you can wait that long.
 

HotRodPC

Administrator
Staff member
Admin
Joined
Aug 29, 2010
Posts
47,008
Reaction score
8,977
Location
OKC, OK
First Name
HotRod
Truck Year
85 K20 LWB
Truck Model
Silverado
Engine Size
454 - Turbo 400 - 3.73
I daily drive a stock 305, and it’s not a race car, but it can at least get out of its own way. The 305 is held back by its puny bore, and that’s why people flock to the 350 because it’s a better performance platform. That being said, the same bolt ons and tricks to boost power are universal to SBCs. The 601 truck heads are almost as good as the 416 heads, and both are HO heads by 305 standards. You can port and polish these heads up to 2.02/1.6 valves I’m pretty sure. A cam upgrade helps. I don’t like anything that screws with vacuum too much on a daily or semi-daily driver so something like the Comp 12-300-4 or equivalent seems sufficient. An aluminum intake like the Edelbrock 2101 might help marginally, but it’s so much easier to assemble with the lighter intake. A good ignition system (standard HEI), proper gearing, and a more advanced base timing without making it ping help. Headers and a deletion of the cat and air injection should bring it home. I haven’t tested this out yet, but this hypothetical motor should be around a 300 hp plant. Not bad, but the same investment yields you more in a 350, and they’re pretty ubiquitous. That’s why people shy away from them for the most part. I like the little engine, though. It’s more reliable than I could have ever hoped for, and when it gets tired, I’ll rebuild it, do the aforementioned upgrades, and keep on trucking.
The other reason people usually get away from them is, the rebuild kit is more expensive than the 350. So by the time you pay the cost difference in the rebuild kit, machine work cost the same, then for the difference you can usually source a rebuildable 350 core so you break even and get the more powerful engine. I've been told there's not a huge difference in mpg either between the 2 so you may as well have the more power there when you want it for the same money. ME? I never get better mpg with more power cuz it's not there when and if I need it, cuz if it's there, I'm going to use it just because I can and there goes the gas gauge. :rofl:
 

bigcountry78

Full Access Member
Joined
Apr 16, 2013
Posts
3,600
Reaction score
8,589
Location
Hickory, North Carolina
First Name
James
Truck Year
1978
Truck Model
K10 Custom Deluxe
Engine Size
350
I think most people overlook how much axle gears affect your power. My cousin has an 84 Sierra that left the factory with the 305 and 3.08 gear ratio. He swapped in a set of 3.73 axles from my parts truck and he said it made a huge difference. He was running 33’s at that point. I’ve also heard that engine go screaming by in the dark when his auto hubs broke, and the only way he could get through the mud that night was to put it in low range and floor it. It’s a tough little engine.
 

78C10BigTen

Full Access Member
Joined
Apr 12, 2017
Posts
15,476
Reaction score
23,687
Location
pennsylvannia
First Name
Ted
Truck Year
1978
Truck Model
C10 BIG TEN
Engine Size
350
There's a guy with a machine shop in town running 11s with a 305. It gets some work done for the little powerplant.

xc_hide_links_from_guests_guests_error_hide_media
Crazy to think a lil 305 can make the wheels come off the ground!
 

K201979

Full Access Member
Joined
Oct 22, 2018
Posts
879
Reaction score
862
Location
Winona, missouri
First Name
Hippie
Truck Year
1979
Truck Model
K20
Engine Size
350ci
Whats the story on 416 heads. Im seeing some on craigslist around $275. That about normal?
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
Those are the 81-86 Camaro HO heads. If they’re refurbished, and you can get documentation to that affect, I’d say absolutely. If they’re just old, pulled heads, I’d say no way, more like $150, $175 tops. People put them on 350s to boost compression or work them for the few performance 305s out there, and they aren’t trash heads, especially considering they’re from the late smogger era.
 

K201979

Full Access Member
Joined
Oct 22, 2018
Posts
879
Reaction score
862
Location
Winona, missouri
First Name
Hippie
Truck Year
1979
Truck Model
K20
Engine Size
350ci
Whats the pros/ cons them vs. vortecs? I know nothing about heads(obviously) and i havent researched, just happened to be cuirios about them about the time u mendtioned them. Had thoughts of maybe someday votec heads on my 350, now not sure which direction to go. Again, no research yet and just thinking way down the road. So, thanks for the info.
 

Latest posts

Forum statistics

Threads
41,856
Posts
903,621
Members
33,370
Latest member
mitchell1128
Top