305 to 350 swap?
#1
Junior Member
Thread Starter
Join Date: Jan 2015
Posts: 14
Likes: 0
Received 3 Likes
on
2 Posts
Car: 1983 Camaro z28
Engine: 5.0L 305
Transmission: 4 speed auto
305 to 350 swap?
So I got a 83 z28 with a 305 in it. Its in running condition, but a lot of work needs to go in to get the power up in it. Since the 305 was never intended to be a high performance engine Im thinking swapping it out for a 350 will produce better results in the future.
Is it worth doing the swap? or should i keep the original engine?
Is it worth doing the swap? or should i keep the original engine?
The following 2 users liked this post by Mr.cannonrider:
350T-Top (11-15-2023), newbcarguy (11-19-2023)
#2
Supreme Member
Re: 305 to 350 swap?
So I got a 83 z28 with a 305 in it. Its in running condition, but a lot of work needs to go in to get the power up in it. Since the 305 was never intended to be a high performance engine Im thinking swapping it out for a 350 will produce better results in the future.
Is it worth doing the swap? or should i keep the original engine?
Is it worth doing the swap? or should i keep the original engine?
The following 2 users liked this post by midias:
newbcarguy (11-19-2023), Thirdgen4me2 (02-27-2024)
The following users liked this post:
newbcarguy (11-19-2023)
#4
Supreme Member
The following users liked this post:
newbcarguy (11-19-2023)
#5
Member
Join Date: Jun 2014
Location: South Jersey
Posts: 360
Likes: 0
Received 3 Likes
on
3 Posts
Car: 88 GTA Notch/01'WS-6 VERT
Engine: 5.0 LB-9/5.7 LS-1
Transmission: 700R-4/4L60
Axle/Gears: borg warner 3.27's
Re: 305 to 350 swap?
It basically is up to you in the long run I would say yes unless it's a super low mileage all original car but hey that's my .....
The following users liked this post:
newbcarguy (11-19-2023)
#6
Moderator
iTrader: (14)
Join Date: Mar 2000
Location: Littleton, CO USA
Posts: 43,169
Likes: 0
Received 35 Likes
on
34 Posts
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Headers, free-flowing exhaust, and a cam swap will do wonders to how the 305 will run.
Doing headers, free-flowing exhaust, and the same cam in a 350 would about double the improvement (not the power, the improvement over the stock 305).
Doing a 350 swap in place of a 305 without doing headers and free-flowing exhaust won't yield much better results than the 305 with headers, free-flowing exhaust, and cam swap.
Do you see a common theme here?
Pretty much all of the factory 350s were dogs as well. The ones that weren't won't be on eBay or craigslist. Meaning more details need to be addressed than "350".
Doing headers, free-flowing exhaust, and the same cam in a 350 would about double the improvement (not the power, the improvement over the stock 305).
Doing a 350 swap in place of a 305 without doing headers and free-flowing exhaust won't yield much better results than the 305 with headers, free-flowing exhaust, and cam swap.
Do you see a common theme here?
Pretty much all of the factory 350s were dogs as well. The ones that weren't won't be on eBay or craigslist. Meaning more details need to be addressed than "350".
The following users liked this post:
Scott's 83' Z (08-21-2023)
#7
Supreme Member
iTrader: (13)
Join Date: Dec 2002
Location: Bowdon, GA.
Posts: 2,535
Likes: 0
Received 16 Likes
on
14 Posts
Car: 1988 Camaro
Engine: 355, 10.34:1, 249/252 @.050", IK200
Transmission: TH-400, 3500 stall 9.5" converter
Axle/Gears: Ford 9", detroit locker, 3.89 gears
Re: 305 to 350 swap?
If you are wanting performance out of your car and plan to mod the engine, then yes the 350 swap is what you need.. It's a better base to work with, bigger bore, not limited like the 305.
The 305 is the small block with asthma.. It can't breath good.
Like five7kid said though, stock 350's for the most part are dogs too.. Unless you get a 70/71 LT1 350 or a 96-00 vortec 350, but all 350's will respond better to mods than a 305 will.
Keeping your stock engine, well if you have the room to do so and if you think you may sell the car 10, 15, 20 years from now it would be worth while maybe, but storing an engine for 20 years in hopes that it will help the resell vaule of a car with quite a lot of miles on it is not very practical
The 305 is the small block with asthma.. It can't breath good.
Like five7kid said though, stock 350's for the most part are dogs too.. Unless you get a 70/71 LT1 350 or a 96-00 vortec 350, but all 350's will respond better to mods than a 305 will.
Keeping your stock engine, well if you have the room to do so and if you think you may sell the car 10, 15, 20 years from now it would be worth while maybe, but storing an engine for 20 years in hopes that it will help the resell vaule of a car with quite a lot of miles on it is not very practical
The following users liked this post:
newbcarguy (11-19-2023)
Trending Topics
#8
Senior Member
Join Date: May 2012
Location: Woodstock, IL
Posts: 582
Likes: 0
Received 1 Like
on
1 Post
Car: 1984 Trans Am Recaro Edition
Engine: 355 L98 Vortec 226/234 custom cam
Transmission: TKO-600
Axle/Gears: On borrowed time...
Re: 305 to 350 swap?
At the tail end of my swap that I started last year.
Bought a L98 350 that came from a 89 IROC ... It's a roller block..good thing
Had it rebuilt. Bored .030 over. Custom cam. Vortec heads off a 99 blazer.
dyno don headers. Magnaflow exhaust. Estimating around 400hp at the crank.
Bought a L98 350 that came from a 89 IROC ... It's a roller block..good thing
Had it rebuilt. Bored .030 over. Custom cam. Vortec heads off a 99 blazer.
dyno don headers. Magnaflow exhaust. Estimating around 400hp at the crank.
The following users liked this post:
newbcarguy (11-19-2023)
#9
Member
Join Date: Jan 2006
Location: South Pekin, IL
Posts: 137
Likes: 0
Received 3 Likes
on
2 Posts
Car: 87 Fomula, bought new, October 86
Engine: 305 Quadrajet,
Transmission: 700R4
Axle/Gears: 9bolt now in, starting on body work
Re: 305 to 350 swap?
Did you see the PowerBlock tv series they did on using a Summit block and other parts to make a nice 383 combo? This was about a year ago, I think. Much better low end torque and about double the hp. It seems like the lowest cost way to get my 87 Formula 305 back on the road unless Overhaulin' wants to use my car for an episode...
The following users liked this post:
newbcarguy (11-19-2023)
#10
Member
Join Date: Jan 2011
Location: Saratoga Area, New York
Posts: 446
Likes: 0
Received 1 Like
on
1 Post
Car: 1990 Formula Firebird
Engine: 305 TBI (LO3)
Transmission: WC T-5 out of an 88 T/A
Axle/Gears: 10 bolt, 3.42 & Torsen Posi
Re: 305 to 350 swap?
So I got a 83 z28 with a 305 in it. Its in running condition, but a lot of work needs to go in to get the power up in it. Since the 305 was never intended to be a high performance engine Im thinking swapping it out for a 350 will produce better results in the future.
Is it worth doing the swap? or should i keep the original engine?
Is it worth doing the swap? or should i keep the original engine?
The following users liked this post:
newbcarguy (11-19-2023)
#11
Junior Member
Join Date: Nov 2014
Location: Texas
Posts: 30
Likes: 0
Received 1 Like
on
1 Post
Car: 89 Formula Firebird
Engine: 305/5.0 LO3 TBI
Transmission: T5 5 speed
Axle/Gears: 3.08 limited slip
Re: 305 to 350 swap?
I'll throw in here because I've been looking at the same thing. Do the swap. All the performance stuff the threads talk about for the 305 don't seem to exist anymore. 350 parts are plentiful and cheaper.
The following users liked this post:
newbcarguy (11-19-2023)
#12
Senior Member
Join Date: Feb 2011
Location: Long Island, NY
Posts: 653
Likes: 0
Received 4 Likes
on
3 Posts
Car: 87 Trans Am, 99 WS6, 16 Mustang GT
Engine: LB9, LS1
Transmission: 700R4, T56
Axle/Gears: 3.42 Posi, 4.10 Posi
Re: 305 to 350 swap?
Not trying to say dumping the 305 is a bad move, I'm doing it myself, just saying you can work with them if you want to.
#13
Junior Member
Join Date: Nov 2014
Location: Texas
Posts: 30
Likes: 0
Received 1 Like
on
1 Post
Car: 89 Formula Firebird
Engine: 305/5.0 LO3 TBI
Transmission: T5 5 speed
Axle/Gears: 3.08 limited slip
Re: 305 to 350 swap?
The heads won't, 58cc chamber (305) vs 64cc (305). The heads are the trouble I'm having, don't want to modify 350 heads to work. I'm keeping my 305 for now, only 60 thousand miles on it, but most of the stuff you find with the search function is 14 years old and a lot is not available. I'm getting a crash course in engine building by cross referencing specs from the old threads with what is available now.
#15
Re: 305 to 350 swap?
Swap complete. A few updates for those tracking:
1- new blueprint 350 crate. I didnt go 383 as i felt the 390hp/420# would be plenty. Had a shop do the work, (lucky to find a shop that would, most wouldn't touch it). There was a lot more labor and custom work installing the motor than i understood.
2-added headers, 3 inch exhaust
3-with the 305, the exhaust note was no louder than a civic. With the crate motor and headers, the same muffler is over the top loud, putting a magnaflow on it with some baffling to make it drivable
4-went 350 thinking the current cooling system and rearend etc would be good. Well... it overheats on a hot day now, so adding a four core radiator, dual fans.
5-with taller tires (car is sitting on lowering springs with riddlers now), and the 5 speed, the car just feels like its geared too high. Gears are long. Going to swap rearend gears to 3.73 this winter.
Its a fantastic car now, but we are deep in the rabbit hole, and by admission I'm not a mechanic.
1- new blueprint 350 crate. I didnt go 383 as i felt the 390hp/420# would be plenty. Had a shop do the work, (lucky to find a shop that would, most wouldn't touch it). There was a lot more labor and custom work installing the motor than i understood.
2-added headers, 3 inch exhaust
3-with the 305, the exhaust note was no louder than a civic. With the crate motor and headers, the same muffler is over the top loud, putting a magnaflow on it with some baffling to make it drivable
4-went 350 thinking the current cooling system and rearend etc would be good. Well... it overheats on a hot day now, so adding a four core radiator, dual fans.
5-with taller tires (car is sitting on lowering springs with riddlers now), and the 5 speed, the car just feels like its geared too high. Gears are long. Going to swap rearend gears to 3.73 this winter.
Its a fantastic car now, but we are deep in the rabbit hole, and by admission I'm not a mechanic.
The following 4 users liked this post by 1991whiteRS:
#16
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: S. UTAH
Posts: 1,245
Likes: 0
Received 162 Likes
on
134 Posts
Car: 1989 IROC-Z 305 LB9 AT Convertible
Engine: LB9 305
Transmission: AT
Re: 305 to 350 swap?
ARE you the OP?
NICE to hear an update! So many Threads die without conclusion or updates.
NICE to hear an update! So many Threads die without conclusion or updates.
#18
Junior Member
Re: 305 to 350 swap?
I've got an 84 Camaro Berlinetta (305/Q-jet) that I'm considering doing the 383 swap to. Did you go with EFI, or keep the 4BBL carb? And which headers worked with the swap, since the 305 exhaust manifolds are too restrictive. Let me know if you can help, ok? Jim email:sales@scumbackspeakers.com
Thanks in advance!
Thanks in advance!
Swap complete. A few updates for those tracking:
1- new blueprint 350 crate. I didnt go 383 as i felt the 390hp/420# would be plenty. Had a shop do the work, (lucky to find a shop that would, most wouldn't touch it). There was a lot more labor and custom work installing the motor than i understood.
2-added headers, 3 inch exhaust
3-with the 305, the exhaust note was no louder than a civic. With the crate motor and headers, the same muffler is over the top loud, putting a magnaflow on it with some baffling to make it drivable
4-went 350 thinking the current cooling system and rearend etc would be good. Well... it overheats on a hot day now, so adding a four core radiator, dual fans.
5-with taller tires (car is sitting on lowering springs with riddlers now), and the 5 speed, the car just feels like its geared too high. Gears are long. Going to swap rearend gears to 3.73 this winter.
Its a fantastic car now, but we are deep in the rabbit hole, and by admission I'm not a mechanic.
1- new blueprint 350 crate. I didnt go 383 as i felt the 390hp/420# would be plenty. Had a shop do the work, (lucky to find a shop that would, most wouldn't touch it). There was a lot more labor and custom work installing the motor than i understood.
2-added headers, 3 inch exhaust
3-with the 305, the exhaust note was no louder than a civic. With the crate motor and headers, the same muffler is over the top loud, putting a magnaflow on it with some baffling to make it drivable
4-went 350 thinking the current cooling system and rearend etc would be good. Well... it overheats on a hot day now, so adding a four core radiator, dual fans.
5-with taller tires (car is sitting on lowering springs with riddlers now), and the 5 speed, the car just feels like its geared too high. Gears are long. Going to swap rearend gears to 3.73 this winter.
Its a fantastic car now, but we are deep in the rabbit hole, and by admission I'm not a mechanic.
#19
Re: 305 to 350 swap?
After research and thinking about budget, we went with the 670 cfm Carburetor, part of the crate motor set up. This simplified the entire build. You just need to deal with the fuel lines and fuel pump. Finding the right header for this set up was key too. Doug's headers. They are excellent quality. I kept my original cooling system, as i was hoping to match the driveline, cooling, brakes, etc., without rebuilding entire car. Truth, it worked, but shortly after did a massive upgrade on cooling system as well to keep temps down.
#20
Junior Member
Re: 305 to 350 swap?
After research and thinking about budget, we went with the 670 cfm Carburetor, part of the crate motor set up. This simplified the entire build. You just need to deal with the fuel lines and fuel pump. Finding the right header for this set up was key too. Doug's headers. They are excellent quality. I kept my original cooling system, as i was hoping to match the driveline, cooling, brakes, etc., without rebuilding entire car. Truth, it worked, but shortly after did a massive upgrade on cooling system as well to keep temps down.
Jim
Last edited by Bearhead; 11-13-2023 at 04:10 PM.
#21
Re: 305 to 350 swap?
Mine was a RS, with the 305/5 speed. Which is the perfect sleeper. I did upsize the tires / wheels and lowered it (not quite a sleeper, but clean as can be). Next move is a lower rearend, i'm geared too high.
The following users liked this post:
dmccain (11-14-2023)
#23
Junior Member
Re: 305 to 350 swap?
This is my 84, with a Z28 front end. The paint is something I came up with years ago. Like to have this car go as good as it looks...for once. LOL
I gave it to my nephew in 2013, but he's been unable to upgrade it in CO since they adopted the CARB regulations. He already bought a complete
Hotchkiss suspension kit, etc for it, too.
84 Berlinetta w/Z28 front end, custom paint.
I gave it to my nephew in 2013, but he's been unable to upgrade it in CO since they adopted the CARB regulations. He already bought a complete
Hotchkiss suspension kit, etc for it, too.
84 Berlinetta w/Z28 front end, custom paint.
The following users liked this post:
dmccain (11-14-2023)
#24
Junior Member
Join Date: Nov 2023
Location: seattle
Posts: 1
Received 0 Likes
on
0 Posts
Car: 83'Berlinetta(t-tops) and 87 sport
Engine: 350sbc
Transmission: 700r4
Re: 305 to 350 swap?
Yes swap please.
I Have a question for some options..... First off I have a 1987. 2.8 MPFI V6 sport coupe with t-tops, got it cheap. Did a top end myself. She runs great and the body would blue paint. Original looks sexy. However, I also bought an 83 berlinetta sport coupe with t-tops, stock 305 700r4, I bought a running 350 out of an 86 Silverado, just to learn I'm doing the complete swap using that trans. In the process of disassembling the 350. Doing the rebuild and putting it in the berlinetta, everything is the body on the berlinetta is not that great, t-tops interior wheels, brakes seats – everything is nowhere near as nice as the blue Camaro. Does anybody think I should use all my parts from the blue car and detail out the berlinetta or just say f*** it and drop the 350 into the blue car using all the parts from the berlinetta? Also the 305 block only is for sale if anybody needs one.
I Have a question for some options..... First off I have a 1987. 2.8 MPFI V6 sport coupe with t-tops, got it cheap. Did a top end myself. She runs great and the body would blue paint. Original looks sexy. However, I also bought an 83 berlinetta sport coupe with t-tops, stock 305 700r4, I bought a running 350 out of an 86 Silverado, just to learn I'm doing the complete swap using that trans. In the process of disassembling the 350. Doing the rebuild and putting it in the berlinetta, everything is the body on the berlinetta is not that great, t-tops interior wheels, brakes seats – everything is nowhere near as nice as the blue Camaro. Does anybody think I should use all my parts from the blue car and detail out the berlinetta or just say f*** it and drop the 350 into the blue car using all the parts from the berlinetta? Also the 305 block only is for sale if anybody needs one.
#25
Junior Member
Re: 305 to 350 swap?
Did you convert to a true dual exhaust system, or still the single Y pipe setup?
#26
Member
Re: 305 to 350 swap?
How much torque is the T5-WC rated for? The trans is why I kept the 305 L69, I can't afford a Tremec.
#27
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,123
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: 305 to 350 swap?
How much torque is the T5-WC rated for?
I WILL tell you though, the first 4 or 5 I tore up, were with my OE 305. (83 L69)
#28
Member
Re: 305 to 350 swap?
LOL. Thanks for the encouragement SofaK!
#29
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,123
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: 305 to 350 swap?
Thanks for the encouragement
I've even heard of people that have tore em up with 6-cyls, but that's just hearsay, I have no experience whatsoever with 6-cyls. (and intend to keep it that way) Just, tearing up T-5s. Which is REEEEEEEEL EEEEEZZZZY.
#30
Supreme Member
Re: 305 to 350 swap?
#31
Member
Re: 305 to 350 swap?
I had a regular t5 behind a zz4 for years. I did lots of burnouts, and beat it pretty well but was careful. I'd call it "cautiously abusive". It held up till I removed it and swapped a t56. I think it's doable to keep one alive behind a 350. How long and how much it will handle is certainly a question and your results may vary!
#32
Junior Member
Re: 305 to 350 swap?
Looking to go with a 383 410hp 87 octane BluePrint engine long block to swap in and take my 305 V8 out. Does anyone know if the 305 harmonic balancer and pulleys work on a 383 block? Trying to minimize the whole swap out of the AC, PS, ALT, etc accessories for the new motor. This is what I'm hoping to put in.
https://blueprintengines.com/collect...-for-87-octane
Thanks in advance!
Jim
https://blueprintengines.com/collect...-for-87-octane
Thanks in advance!
Jim
#33
Member
Re: 305 to 350 swap?
The pulleys will all be the same. The balancer will depend on the crank used I think
#34
Junior Member
Re: 305 to 350 swap?
#35
Junior Member
Re: 305 to 350 swap?
After more research, it turns out the 383/400 cranks use a different harmonic balancer than the 305/350 setup. So I'll need to buy a new HB for the 383 stroker. Does anyone have experience with the flex plate & flywheel compatibility between the the 305 and a 383/400 block?
#36
Junior Member
#37
Junior Member
#38
Supreme Member
Join Date: Oct 2000
Location: Park City, UT
Posts: 1,971
Received 298 Likes
on
204 Posts
Car: '92 Corvette, '89 1/2-a-'Vette
Engine: LT1, L98
Transmission: ZF6, ZF6
Axle/Gears: 3.45, 3.31
Re: 305 to 350 swap?
On neutral balanced engines, such as the 305, 350, and every other SBC (besides the 400), it balances nothing and is strictly a harmonic damper and pulley flange.
On externally balanced engines, such as a 383, 400, Ford, AMC and other V8's, it also serves as a balancer, as well as a harmonic damper and pulley flange. So what to call it?
IDK. Either? Both?
I call 'em Dampers, on 265, 283's, 302's, 305's, 307's, 327's, and 350's. I call them Balancers, on 334's, 383's and 400's....and "the other guys" engines.
Thread
Thread Starter
Forum
Replies
Last Post