Engine Swap Everything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.

305 to 350 swap for my Firebird

Thread Tools
 
Search this Thread
 
Old 04-16-2024, 07:14 PM
  #1  
Junior Member
Thread Starter
 
Jacobvanhorn1's Avatar
 
Join Date: Apr 2024
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
305 to 350 swap for my Firebird

I have an 87 T/an and I want to ditch the old 305 and put in a 350. But I have no idea what I’m doing and if I have to make any modifications to the engine bay. And will 4 speed auto work with the 350 or will I need an entire new transmission? Also the 305 is carbed. This is my first project car.
Old 04-16-2024, 07:19 PM
  #2  
Member

iTrader: (2)
 
ratfink6923's Avatar
 
Join Date: Jul 2011
Location: Tampa, FL
Posts: 136
Received 19 Likes on 17 Posts
Car: 15 Ram, 88 IROC, 92 RS
Engine: 5.0
Transmission: Auto
Axle/Gears: 3.42 (4th Gen)
Re: 305 to 350 swap for my Firebird

Transmission will be fine to keep. Make sure you go with an 87 or up 350, otherwise you'll need a different flex plate.

Otherwise, the swap is pretty straight forward
Old 04-16-2024, 07:30 PM
  #3  
Supreme Member

iTrader: (1)
 
sofakingdom's Avatar
 
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 for my Firebird

The 305 and 350, within the same year range, are IDENTICAL externally. Everything that bolts to one can be unbolted and bolted back up to the other. As far as year range, details matter; we'd have to know what years of 305 & 350 you're working with, to tell you which parts you need.

The transmissions in 305 & 350 cars of the same body style ("sportiness") are, AFAIK, IDENTICAL IN EVERY WAY. Bolt right up and work the same. Meaning, your trans will work just fine with a 350. Not "optimum" maybe, there's of course always room for improvement, but "fine" in the sense of not needing ... something unique to the 350.

Depending on the carb and intake manifold and the 350, you might be able to just swap all that over from the 305 to the 350. It'll all just bolt right up, subject to the 87-up vs 86-back intake bolt angle difference, which is easily overcome.
Old 04-17-2024, 06:24 AM
  #4  
Supreme Member

 
ironwill's Avatar
 
Join Date: Jan 2008
Posts: 1,034
Received 420 Likes on 301 Posts
Car: 1986 IROC Z
Engine: 5.0 TPI
Transmission: 700R4
Axle/Gears: 3.23 Posi
Re: 305 to 350 swap for my Firebird

Originally Posted by Jacobvanhorn1
I have an 87 T/an and I want to ditch the old 305 and put in a 350. But I have no idea what I’m doing and if I have to make any modifications to the engine bay. And will 4 speed auto work with the 350 or will I need an entire new transmission? Also the 305 is carbed. This is my first project car.
Other than possibly requiring a different flex plate, it's a straight bolt-in swap.


Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Hurley_turley
Engine Swap
1
06-06-2008 01:45 PM
cyko83
Tech / General Engine
29
03-08-2008 12:27 PM
kbcattle
Engine Swap
4
07-15-2003 02:00 PM
britered86transam
Engine Swap
2
03-15-2002 12:36 AM



Quick Reply: 305 to 350 swap for my Firebird



All times are GMT -5. The time now is 10:57 PM.