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305 -> 350 Bolt-In Swap?

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Old 12-09-2010 | 10:28 PM
  #1  
Phantom552's Avatar
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From: Mesa, AZ
Car: 92 Camaro RS
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
305 -> 350 Bolt-In Swap?

Just a quick question before I get ready to actually try it & see what happens.

First off, I have a 1992 Camaro RS with the factory 305 cid TBI engine, and an engine that I haven't had time to identify properly as of yet, but it's a '70s era Chevy 350.

Mainly, im wondering if it would be reasonably possible to swap the factory 305 out for the chevy 350, and exactly how much of a pain it would be to get everything to bolt up correctly.

If anyone needs more specific information in order to provide an answer, just let me know & ill get it for ya. Thanks!
Old 12-09-2010 | 10:41 PM
  #2  
DAREDEVIL 1's Avatar
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From: Bradenton FL
Car: CAMARO,GMC SUBURBAN DUALLY,RACEBOA
Engine: 305 TBI( soon 383),350Vortec
Transmission: 700 turbo
Re: 305 -> 350 Bolt-In Swap?

Originally Posted by Phantom552
Just a quick question before I get ready to actually try it & see what happens.

First off, I have a 1992 Camaro RS with the factory 305 cid TBI engine, and an engine that I haven't had time to identify properly as of yet, but it's a '70s era Chevy 350.

Mainly, im wondering if it would be reasonably possible to swap the factory 305 out for the chevy 350, and exactly how much of a pain it would be to get everything to bolt up correctly.

If anyone needs more specific information in order to provide an answer, just let me know & ill get it for ya. Thanks!
I dont see any problem, but why not build a 383 ???
The blocks are / should be the same.
Old 12-09-2010 | 11:40 PM
  #3  
Phantom552's Avatar
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From: Mesa, AZ
Car: 92 Camaro RS
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: 305 -> 350 Bolt-In Swap?

I know, a 383 would be a lot more fun, but right now the 305 is blown & i need the car for work, so im just trying to get it on the road again (relatively) quickly & cheaply.
Old 12-09-2010 | 11:44 PM
  #4  
DAREDEVIL 1's Avatar
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From: Bradenton FL
Car: CAMARO,GMC SUBURBAN DUALLY,RACEBOA
Engine: 305 TBI( soon 383),350Vortec
Transmission: 700 turbo
Re: 305 -> 350 Bolt-In Swap?

Originally Posted by Phantom552
I know, a 383 would be a lot more fun, but right now the 305 is blown & i need the car for work, so im just trying to get it on the road again (relatively) quickly & cheaply.
Well, i am selling my 305 TBI with the tranny and everything for cheap right now...lol

Since i am going with a 383 !!!! MMMMHHH
Old 12-10-2010 | 01:10 AM
  #5  
Blown84Bird's Avatar
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From: phx,az
Car: 84 firebird, 85 transam
Engine: 350 SBC Or 7.07 Tonys,305stock
Transmission: Big Ugly, 700r4
Axle/Gears: 4th gen rear disk 3.42 lsd,9 bolt
Re: 305 -> 350 Bolt-In Swap?

Intake bolt pattern is a little different. Center two bolts are at a different angles. Injectors are different from What I understand simple fix there get 454 tBI injectors should net a few pony's also
and if all. Else fails do a search on tgo
Good luck
Old 12-10-2010 | 06:41 AM
  #6  
Phantom552's Avatar
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Joined: Dec 2010
Posts: 18
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From: Mesa, AZ
Car: 92 Camaro RS
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: 305 -> 350 Bolt-In Swap?

Any idea if the 305 transmission would bolt up? Or will I need the original 350 transmission?
Old 12-10-2010 | 07:54 AM
  #7  
giszo's Avatar
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Posts: 141
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From: Hungary
Car: 1992 Camaro RS
Engine: 3.1L V6
Transmission: 700-R4
Axle/Gears: 3.23
Re: 305 -> 350 Bolt-In Swap?

Transmission bellhousing on 305 and 350 is the same.
Old 12-10-2010 | 08:03 AM
  #8  
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From: Hollywood, FL
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Re: 305 -> 350 Bolt-In Swap?

Originally Posted by DAREDEVIL 1
Well, i am selling my 305 TBI with the tranny and everything for cheap right now...lol

Since i am going with a 383 !!!! MMMMHHH
How much and what kind of tranny? How many miles? Can that TBI be transformed into TPI? My 305 TPI is blown and I need a cheap engine to get it back on the road.
Old 12-10-2010 | 09:31 AM
  #9  
DAREDEVIL 1's Avatar
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From: Bradenton FL
Car: CAMARO,GMC SUBURBAN DUALLY,RACEBOA
Engine: 305 TBI( soon 383),350Vortec
Transmission: 700 turbo
Re: 305 -> 350 Bolt-In Swap?

Originally Posted by Davidgou
How much and what kind of tranny? How many miles? Can that TBI be transformed into TPI? My 305 TPI is blown and I need a cheap engine to get it back on the road.
The tranny is a R700 and u can transform everything...

make me an offer... miles ( 135 K )

i was thinking ~ 1200 for all
Old 12-10-2010 | 07:04 PM
  #10  
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Re: 305 -> 350 Bolt-In Swap?

Sorry to post in your thread but I find it easier than to start a new one since this has a little somthing to do with it anyway, Im doing a 350 carburated swap also of the same or similar year and I cant find a wiring harness, does anyone know where I can buy one on the internet? Ive looked on Jegs.com, Ebay, and craigslist I cant find one anywhere!
Old 12-11-2010 | 01:46 AM
  #11  
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From: Hollywood, FL
Car: '88 Black GTA, T-tops, digital dash
Engine: 5.7 TPI w/custom chip
Transmission: 700R4
Axle/Gears: 9 bolt 327 posi
Re: 305 -> 350 Bolt-In Swap?

Originally Posted by 1sicFireBird
Sorry to post in your thread but I find it easier than to start a new one since this has a little somthing to do with it anyway, Im doing a 350 carburated swap also of the same or similar year and I cant find a wiring harness, does anyone know where I can buy one on the internet? Ive looked on Jegs.com, Ebay, and craigslist I cant find one anywhere!
You could post in "Parts Wanted" forum or try the local junk yard? I don't think you even need to replace the wiring harness because your computer is not going to control the transmission converter lockup anymore (if yours is auto) and there are no more EFI issues to control either, off course. Why not just leave it there? There are specific instructions in other threads so we don't hack this one. I hope I didn't do it already...
Old 12-12-2010 | 04:21 AM
  #12  
Phantom552's Avatar
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Joined: Dec 2010
Posts: 18
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From: Mesa, AZ
Car: 92 Camaro RS
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
Re: 305 -> 350 Bolt-In Swap?

Ok, so heres a little more info for clarification.

The car is a 1992 Camaro RS

The engine it currently has is the stock 305 TBI

The engine Im hoping to be able to put in it is a 70's era 350 (Carbeurated) which supposedly came out of a 70-something chevy van.

The transmission is the stock A4 for the 305

I'm wondering:

1) Will the 350 bolt into the car without too much trouble
2) Will the stock 305 Transmission bolt up & work with the 350
3) Assuming 1 & 2 are both yes, what all will I have to do to (obviously) get the fuel delivery & ignition going with the 350, and what (if any) modifications or changes will I need to make in order to get the car running, street legal, and (hopefully) able to pass emissions. (Thankfully, AZ's requirements for the latter are fairly low) AKA, able to get me back & forth to work.


The reason for all of this being I'm wondering if its more financially feasible to eat the cost of rebuilding the 305 (which I'm not a huge fan of anyway), or to swap in the 350 that has been just collecting dust in the back of a shop for the last several years (The 350 is -- count it -- free, so the cost there would entirely be reliant upon the 3 questions above).

Thanks again all!
Old 12-12-2010 | 09:52 AM
  #13  
DAREDEVIL 1's Avatar
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Joined: Jan 2010
Posts: 454
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From: Bradenton FL
Car: CAMARO,GMC SUBURBAN DUALLY,RACEBOA
Engine: 305 TBI( soon 383),350Vortec
Transmission: 700 turbo
Re: 305 -> 350 Bolt-In Swap?

If a engine ..no matter which one..sits in a shop for years..u need to go thru it anyways..so nothing else then rebuilding one ?! IMO
Old 12-12-2010 | 10:16 AM
  #14  
talover111's Avatar
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Joined: Feb 2007
Posts: 122
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From: pennsylvania, united states
Car: 1985 & 1988 trans am
Engine: 350 tpi ; 355
Transmission: 700r4 auto; converting to 6 speed
Axle/Gears: 9 bolt 3:27 posi; 2.73 open
Re: 305 -> 350 Bolt-In Swap?

well the 305 is a 1 piece rear main seal and the 350 is a 2 piece rear main seal so u will need a flex plate for a 2 piece rear main seal small block the 350 will bolt right to the trans other than that and it will sit right in the same spot as the 305 so the motor mounts should work
Old 12-13-2010 | 04:32 PM
  #15  
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
An old saying in the hot rod business: "There's no such thing as a bolt-in."

Well, you might be able to bolt in everything you need, but it's still pretty much true that you're going to have to do some tweaking at some level.

First, 305 to 350: Your 305 exhaust is inadequate. Figure on replacing it all. This is a perfect time to upgrade to headers. The '86-'90 TPI single cat application aftermarket exhaust parts can be purchased that will "bolt in" (with the possible exception of clamps and/or hangers - you know, you'll have to "tweak" them).

Next, the "details" - you know, where the devil resides. As already mentioned, the flexplate. Also, are you going to stick with TBI, or go with the carb on the 350? Either way, you're going to have to do something about some details. The TBI fuel system will have to be adapted in order to run carb. Conversely, the TBI system will have to be at the very least reprogrammed for the 350 (and whatever mods you do to the engine).

If you stick with the TH700R-4 transmission and go with carb, you're going to have to adapt the throttle valve cable to the carb. Getting that wrong will result in a burnt-up transmission. Ditto with the torque converter clutch lock-up - with carb, your computer will be brain dead, and won't lock up the TCC anymore - if you don't do something about that, you'll burn up the transmission.

A 70's truck engine will have terrible heads and dished pistons. Don't be surprised if, after going through all this work, you don't have any more power than the 305 had, and gas mileage will be worse.

Last edited by five7kid; 12-13-2010 at 04:35 PM.
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