Olds 350 to Chevy 350 Swap

[zipties]

so crunched this weekend and got the motor basically done. Fluids are good, new plugs are in, all of the front dress is acocunted for and ready to be attached. I extended the starter wires a good foot and a half and jacket them again, should be good to switch to a remote solenoid later but i'll tinker with that later.

Trans is disconnected because i still need to fill it, and it needs a dipstick. The dipstick it came with was busted, and my only other boot type dipstick is from a square body and it doesn't wanna get comfy.

Primed the motor and then wired it all up and it cranks, barely wants to start though. Carb is leaking (Holley problems.) i have another 1850 i rebuilt a bit ago that i'll throw on. It has spark but still doesn't wanna kick. I'm going to double check my firing order and play with it. Don't wanna kill my battery or the new starter. Worse comes to worse i'll borrow a known good dizzy and test on it.

 

[CopperNick]

Picture of the crank flange says one piece main seal. High probability you will need a year or application specific flex plate that matches the engine's balance needs. You don't mention the source of the engine, i.e. model of car but 86's in a Chev usually came with 4 spd Auto stick; thinking probably the 200R4. Your BOP is the corporate case 3 speed, hence the need for the adapter and spacers.

Get that you want to keep budget and project costs down by running what you brung, thinking that the whole engine swap might be simpler to some degree if you went with the 200. (or even a Chev version of the 350) No adapters, bushings or spacers. The only issue might be the t-mission crossmember and they can be scored fairly easily on line.

There are a couple of operational differences that should be pointed out just as an FYI. One is that the 200R4 does not use a vacuum modulator and engine vacuum to govern when it shifts. Shifting is done based on internal ATF pressure; there is a dedicated TV Cable that is attached to the carb throttle lever and which has to be set at a specific tension-- see the video- for the slush box to shift. The cable is a mechanical communications connection that tells the t-box exactly what the engine is doing and when it is time to shift. There are threads on this board about that.
The other point is that your TH350 (or possibly a 400), is a three speed; the 200R4 has four, 4th being an overdrive that is nice for the highway.
The driveshaft should be okay for re-use as is. and the 200 uses a mechanical speedo cable which should also plug in and run as is. You might have to pull the speedo drive and change the drive gear if you find that your actual speed vs what the speedo is supposed to be saying is too out of whack but that is a one bolt and out and nothing too substantial in the road of it all.

Whatever you decide, any problems, post 'em. someone lurking around on the site should be able to kite you an answer or place to go look/ask.



Nick

 

[zipties]

Picture of the crank flange says one piece main seal. High probability you will need a year or application specific flex plate that matches the engine's balance needs. You don't mention the source of the engine, i.e. model of car but 86's in a Chev usually came with 4 spd Auto stick; thinking probably the 200R4. Your BOP is the corporate case 3 speed, hence the need for the adapter and spacers.

Get that you want to keep budget and project costs down by running what you brung, thinking that the whole engine swap might be simpler to some degree if you went with the 200. (or even a Chev version of the 350) No adapters, bushings or spacers. The only issue might be the t-mission crossmember and they can be scored fairly easily on line.

There are a couple of operational differences that should be pointed out just as an FYI. One is that the 200R4 does not use a vacuum modulator and engine vacuum to govern when it shifts. Shifting is done based on internal ATF pressure; there is a dedicated TV Cable that is attached to the carb throttle lever and which has to be set at a specific tension-- see the video- for the slush box to shift. The cable is a mechanical communications connection that tells the t-box exactly what the engine is doing and when it is time to shift. There are threads on this board about that.
The other point is that your TH350 (or possibly a 400), is a three speed; the 200R4 has four, 4th being an overdrive that is nice for the highway.
The driveshaft should be okay for re-use as is. and the 200 uses a mechanical speedo cable which should also plug in and run as is. You might have to pull the speedo drive and change the drive gear if you find that your actual speed vs what the speedo is supposed to be saying is too out of whack but that is a one bolt and out and nothing too substantial in the road of it all.

Whatever you decide, any problems, post 'em. someone lurking around on the site should be able to kite you an answer or place to go look/ask.



Nick

Somewhere in an update I mentioned selling off the 86 block. New motor is a 70 010 block, 4 bolt main, oil spiller but otherwise clean and allegedly low(ish) miles. I went ahead and dug through it, replaced all the gaskets with Summit's kit and painted it. Old BOP corpo 3spd is gone too. Replaced it with a 350C from an F body pontiac. Not going to be running lockup or kickdown for now. Later on I'll build up on it if I feel like it - I have a trans controller laying around that could go to a nice 4l80E if I get another one.

I'm not a huge transmission guy especially auto trans, but I do a fair enough job. I'm not worried about the new drivetrain being able to move this thing.

This weekend I'm gonna dive into the no start. It was around 1AM when I finally started cranking on it so I'm hoping I either mixed up a plug wire or something else minor. I'll post a video either way, always nice to get more eyes on any problems.

 

[CopperNick]

Good to know. The highlight reel for this thread only covered the initial situation, not the ongoing saga. That 010 is a good number block; have one or two of them lurking about the shop as builders if needed.

The 350C is only wired to lockup in third. The harness for it comes with two wires; I had a C in my G-10 before the 700 swap went down. The power switch for the lockup is actually part of the brake light switch. The correct variant of that switch has four contacts, not just two. To defeat or cut off the lockup, what happens when you brake is that the pedal being depressed moves the plunger that actuates the lights and at the same time it breaks the circuit open and cuts power to the lockup on the t-box which turns the lockup off, temporarlly. it resets itself when the pedal is released.

By contrast, the lockup is active in all four gears on the 200 and 700. Same/same to shut it off and reset it.


Nick

 

[zipties]

Good to know. The highlight reel for this thread only covered the initial situation, not the ongoing saga. That 010 is a good number block; have one or two of them lurking about the shop as builders if needed.

By contrast, the lockup is active in all four gears on the 200 and 700. Same/same to shut it off and reset it.


Nick

Was very happy with the score on the block. It's more than enough for what the car's built to do.

The 350C was 'rebuilt' according to the guy I bought it from and I didn't have a reason to doubt him. He was clearing shop with a bunch of built up 3rd gens and S10s. Transmission was a backup with a non-lockup converter. I got it in a package deal since it came with a shift kit which I put in the wife's truck.

All motor needs now is the front dress and a final leak check once that's done: need to get my hands on the proper steel line for the fuel pump too. My line bender must be too primitive for the bend straight from the pump. ill probably have to get an L fitting for it. hopefully the coolant temp sensor doesn't leak or it's just getting smeared with RTV lol.

trans still needs a cooler, which i'm planning on getting a cheap setup from jegs, and a dipstick, which i have yet to figure out. Original dipstick for the 3rd gen does not fit and was hella brittle anyway so that's a no-go. Only other boot type dipstick i had was for a squarebody and it doesn't wanna fit either. I'd rather not use one of those hinky 'universal' setups, but none of the Gs in the nearby yards had a suitable dipstick to take. I'l prbably have to order a ne wone.

 

[zipties]

Almost forgot, after tossing the old carb (it needs a rebuild bad.) and putting the fresh backup on there, I gave it a bit more advance and it fired right up.

Took a vid of the first start. Is there a way to post it here?

 

[Ernest]

Upload the video to YT and then post a link to it here so we can view it.

 

[zipties]

Here's the video.

 

[78Delta88]

Before you button it up you might want to add a timing tab like below...



These usually run about 7.00 to 15.00 USD. Will make it much easier once Alt, AC and PS is mounted.

The one you have on there now came from OEM and was designed for the Sun Scope Probe.

 

[CopperNick]

Now that is INTERESTING!! Might be a bit iffy to get one onto the G-10 timing cover but the Monte is wide open , no fan or rad to negotiate around so Waaay easier.

The actual mfgr is a company called Motorchrome. The E-Bay link can be parsed and will supply a group of vendors that offer that part or similar. They come for both 6-3/4/7 inch and for 8 inch balancers so a need to know your balancer diameter but easy to determine


Already moseyed over and took a peek at it. THX 78Delta88.


Nick