4th Gen ('81-'88): 1987 Engine & Tranny Swap Some Questions
Thread Starter
Joined: Jul 2019
Posts: 20
From: Springfield, MA.
1987 Engine & Tranny Swap Some Questions
So I'm in the middle of swapping out the 305/TH200 for a 350/383 TH400 setup. I have questions:
The engine and tranny are out & on the garage floor already.
1. Looks like the 400 is about the same length (1/4" shorter), the tranny lines are farther back by a couple of inches & shift linkage looks to be in the same spot. But the tranny mounting is further forward and lower than the 200. I'll need a cross brace (and slip yoke from what I read on-line in another forum). Can someone recommend & provide a link to what & where I can buy these?
2. I'm changing the a-arm bushings and motor mounts while I'm in there. I don't expect any fitment issues otherwise. I have a set of Hooker Headers that came with the deal. They came out of a mid 80's Camaro. We'll see if they fit here or not soon enough.
3. Big thing I think in the immediate future is the wiring harness. I labeled all the connections as they were disconnected. Most of the features I will probably not be reusing (i.e. air pump, etc.). I wanna go the EFI route which will come with it's own harnesses and controller. I assume that makes the OEM ECU expendable? And what of the other wiring for reporting back to the gauges? Are their true plug-n-play harnesses available these days for this conversion?
I'm sure I'll have more questions for you guys as I get deeper into this. I haven't even gotten to the rear end yet. But that's enough for now. Thanks in advance for any advice and help.
The engine and tranny are out & on the garage floor already.
1. Looks like the 400 is about the same length (1/4" shorter), the tranny lines are farther back by a couple of inches & shift linkage looks to be in the same spot. But the tranny mounting is further forward and lower than the 200. I'll need a cross brace (and slip yoke from what I read on-line in another forum). Can someone recommend & provide a link to what & where I can buy these?
2. I'm changing the a-arm bushings and motor mounts while I'm in there. I don't expect any fitment issues otherwise. I have a set of Hooker Headers that came with the deal. They came out of a mid 80's Camaro. We'll see if they fit here or not soon enough.
3. Big thing I think in the immediate future is the wiring harness. I labeled all the connections as they were disconnected. Most of the features I will probably not be reusing (i.e. air pump, etc.). I wanna go the EFI route which will come with it's own harnesses and controller. I assume that makes the OEM ECU expendable? And what of the other wiring for reporting back to the gauges? Are their true plug-n-play harnesses available these days for this conversion?
I'm sure I'll have more questions for you guys as I get deeper into this. I haven't even gotten to the rear end yet. But that's enough for now. Thanks in advance for any advice and help.
Joined: Nov 2017
Posts: 1,300
From: Isanti, MN
Chevrolet transmission dimensions, gear ratios and oil quantity (This is a attached link) it gives you dimensions.
Last edited by Jeffs02rwdSS; Dec 21, 2021 at 06:42 PM.
Joined: Nov 2017
Posts: 1,300
From: Isanti, MN
The 305 and 383 are going to use the same wiring. All the sensors will swap right over. And the OEM computer will not be needed if you switch carbs. Switching to EFI will have it's own stand alone harness and require a few different things added. Nothing to difficult to achieve.
Joined: Nov 2017
Posts: 1,300
From: Isanti, MN
Here's another if it is a metric 200 transmission which would change a bunch. Reference Manual: Chapter 2: Transmissions: Transmission Lengths
Joined: Nov 2017
Posts: 1,300
From: Isanti, MN
Thread Starter
Joined: Jul 2019
Posts: 20
From: Springfield, MA.
Thread Starter
Joined: Jul 2019
Posts: 20
From: Springfield, MA.