How to make a little extra power?
#1
How to make a little extra power?
Im kinda new to Building Engines at home by myself I have a L69 305 with very low miles and I want to piece it together to have fun if I do Headers a High performance Carb Edelbrock intake lightweight Pulleys and Valvetrain Upgrades what kind of Power Numbers will I Get...Money is not a Problem
PLEASE NO COMMENTS ABOUT GET A 350
PLEASE NO COMMENTS ABOUT GET A 350
#3
Junior Member
Join Date: May 2018
Location: Omaha, NE
Posts: 80
Received 93 Likes
on
74 Posts
Car: 86 Trans Am
Engine: Carb'd LM7
Transmission: TH400
Axle/Gears: Stock 2.73
Re: How to make a little extra power?
Google is your friend
Throwing money at a 305 isn't advised, but if you stick with bolt-ons they'll transfer over to the 350 you'll wind up with eventually.
Throwing money at a 305 isn't advised, but if you stick with bolt-ons they'll transfer over to the 350 you'll wind up with eventually.
#4
Supreme Member
iTrader: (58)
Re: How to make a little extra power?
The L69 is already pushing it for a 305. It's got decent pistons, head, cam, intake, carb, exhaust, all from the factory. You're not going to see the same gains that you'd see modding a 140hp LG4.
People don't say to get a 350 because of some prejudice against the 305, it's sound advice based on decades of experience.
People don't say to get a 350 because of some prejudice against the 305, it's sound advice based on decades of experience.
#5
Supreme Member
iTrader: (167)
Re: How to make a little extra power?
Upgrades what kind of Power Numbers will I Get...Money is not a Problem
I have a L69 305 with very low miles and I want to piece it together to have fun
#6
Supreme Member
iTrader: (1)
Join Date: Feb 2017
Location: Meriden, CT 06450
Posts: 4,030
Received 511 Likes
on
428 Posts
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: How to make a little extra power?
Search member Ja85z28 and read what he did to his.
#7
Supreme Member
Join Date: Jan 2008
Posts: 1,010
Received 408 Likes
on
295 Posts
Car: 1986 IROC Z
Engine: 5.0 TPI
Transmission: 700R4
Axle/Gears: 3.23 Posi
Re: How to make a little extra power?
Im kinda new to Building Engines at home by myself I have a L69 305 with very low miles and I want to piece it together to have fun if I do Headers a High performance Carb Edelbrock intake lightweight Pulleys and Valvetrain Upgrades what kind of Power Numbers will I Get...Money is not a Problem
PLEASE NO COMMENTS ABOUT GET A 350
PLEASE NO COMMENTS ABOUT GET A 350
What is your issue with replacing the 305 with a 350? If it's $$$, the cost of the above mods to the 305 are close to being enough to cover a Good Wrench crate 350.
Trending Topics
#8
Re: How to make a little extra power?
It’s Like this I don’t need no crazy amount of Horsepower 3rd gens are Fairly light so if I can make a realistic 280-300 RWHP then I will be Fine I’m using the car for Driving in Mountains and twisty Roads it’s not a Drag Car I know I can Swap another Engine I just want to play with the car it’s just for fun...and if the 305 can Handle that amount of Power or produce it easy then I will look into something else
#12
COTM Editor
iTrader: (22)
Join Date: Mar 2001
Posts: 9,904
Likes: 0
Received 1,855 Likes
on
1,270 Posts
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: How to make a little extra power?
Modifying a 305 isn't very rewarding. If you want to keep the 305 then I might suggest doing the typical cheap and free mods and leave it at that.
A supercharger would make quite a bit of difference and be reversible back to stock anytime you want.
A supercharger would make quite a bit of difference and be reversible back to stock anytime you want.
#13
COTM Editor
iTrader: (22)
Join Date: Mar 2001
Posts: 9,904
Likes: 0
Received 1,855 Likes
on
1,270 Posts
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
#15
Supreme Member
Re: How to make a little extra power?
LS swap + turbo $20,000 500rwhp reliable car
Thats about the only option I see anymore for daily drivers
Thats about the only option I see anymore for daily drivers
#16
Supreme Member
Re: How to make a little extra power?
Exhaust and rear axle gearing, best two mods for that machine. Much like the Monte Carlo SS back in the day.
#17
Supreme Member
iTrader: (2)
Join Date: Mar 2014
Location: South Ms
Posts: 4,422
Received 721 Likes
on
490 Posts
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: How to make a little extra power?
I done headers and cam to an LG4 once and it was still a bit slower than my LB9 car I got a few years later to my surprise. If you bother with a 305 you probably wont be happy performance wise. Not saying its not a good engine because they are peppy and run forever, but a 350 is so much better for the $ I would never spend much on a 305.
#18
Supreme Member
Re: How to make a little extra power?
#19
COTM Editor
iTrader: (22)
Join Date: Mar 2001
Posts: 9,904
Likes: 0
Received 1,855 Likes
on
1,270 Posts
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: How to make a little extra power?
Good thing you weren't a pioneer settler heading west from Chicago because you would have run out of supplies and died somewhere in the grass plains of Montana less than halfway to the West coast.
Last edited by QwkTrip; 03-11-2019 at 01:00 PM.
#20
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 9,983
Received 386 Likes
on
329 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: How to make a little extra power?
The 305 in my 1980 Vette was still mild and trapped 110 mph in the low 12s on drag radials with a TH350C and 3.07 gear behind it.
It was a flat top piston, .040" over 305. Ported Vortec 305 heads (059 casting) with 1.94/1.60 valves. Crane 272H10 cam with 1.6 rockers. Edelbrock Victor Jr single plane intake manifold. 500 cfm Edelbrock carb. Long tube headers and a pypes 2.5" dual exhaust with magnaflow mufflers. 3,000 rpm lockup converter in the TH350C. It idled 750 rpm with the a/c on and still pulled down 25 mpg highway.
I also had what amounted to a roller cam L69 with bolt ons in my old G20 van. It was a .030" over Vortec 305 block, flat top 1.56 compression height pistons zero decked, F-car LT1 cam, and 53cc 14022601 heads. An Edelbrock Performer RPM intake, tweaked Q-Jet, recurved HEI, 1.6 roller rockers, Thorley Headers and 2.5" exhaust with a X-pipe before the high flow cats and magnaflow mufflers. With a 2,800 stall converter in a 700r4 and 3.73 gears. It ran a 14.8 @ 94 in the big van. It idled 550 in drive with the a/c on and would get better than 20 mpg running 75 mph.
It was a flat top piston, .040" over 305. Ported Vortec 305 heads (059 casting) with 1.94/1.60 valves. Crane 272H10 cam with 1.6 rockers. Edelbrock Victor Jr single plane intake manifold. 500 cfm Edelbrock carb. Long tube headers and a pypes 2.5" dual exhaust with magnaflow mufflers. 3,000 rpm lockup converter in the TH350C. It idled 750 rpm with the a/c on and still pulled down 25 mpg highway.
I also had what amounted to a roller cam L69 with bolt ons in my old G20 van. It was a .030" over Vortec 305 block, flat top 1.56 compression height pistons zero decked, F-car LT1 cam, and 53cc 14022601 heads. An Edelbrock Performer RPM intake, tweaked Q-Jet, recurved HEI, 1.6 roller rockers, Thorley Headers and 2.5" exhaust with a X-pipe before the high flow cats and magnaflow mufflers. With a 2,800 stall converter in a 700r4 and 3.73 gears. It ran a 14.8 @ 94 in the big van. It idled 550 in drive with the a/c on and would get better than 20 mpg running 75 mph.
Last edited by Fast355; 03-17-2019 at 03:55 PM.
#22
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 9,983
Received 386 Likes
on
329 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: How to make a little extra power?
My brothers old 1980 C10 went into the 13s with the shortblock from the Van. Ported 059s with 1.94/1.60 valves(later those were on the Vette), GM 845 cam, GM dual plane carb intake off a 330 HP 350 HO, Q-Jet, recurved HEI, shorty headers from a 1998 Vortec truck, dual 2.5" exhaust. Using a 3,000 stalled TH350 and 3.08 gears.
#23
Supreme Member
iTrader: (16)
Re: How to make a little extra power?
Originally Posted by ironwill
It's tough to get a 305 to breathe enough to produce significant power; the cylinder heads are the limiting factor, and the small bore size doesn't allow larger valves...
LB9 = 3.736 x 3.480
2JZ = 3.390 3.390
Stock Valve Sizes
LB9 = 1.85/1.50 (two valve)
2JZ = 1.32/1.14 (four valve)
Simply put, a 1.94" valve is all the valve a naturally aspirated 305 will ever need to make great power (for its' size). If your 305 is boosted like mine, then sure you can try to swing 2.00+ valves in there for more room up top, but it's not really needed. It's more about cylinder head flow and cam characteristics when it comes to a naturally aspirated 305, but again, you won't see as much as you would with a larger engine. Free mods are meaningless in my opinion, if you're not going to pull the heads and get a better cam, then don't even bother.
- Rob
#24
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 9,983
Received 386 Likes
on
329 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: How to make a little extra power?
Thread
Thread Starter
Forum
Replies
Last Post
kkirch15
Exterior Parts Wanted
3
07-25-2015 09:08 AM
SomethingWild
Tech / General Engine
47
12-14-2011 08:23 PM