Enigne swap 350 TBI L05 in Caprice Classic Station with Olds 307

[cheekbug]

hi all,

i am from Germany so sorry for my bad english. Lots of questions

I will buy a 1989 G20 Van with 350 TBI and i would like to swap that Enginge in my 1990 Caprice Classic Station with Olds 307 Engine.
Can anyone of you guys tell me, what things i have to be aware off?

I know that i will need an adapter for the Transmission, cause i want to keep my BOP th200 4r, instead of the th700 R4. Or will it fit, without problems? I mean what about the lenght of the drive shaft?

What about the Oil sump of the 350 TBI Engine in the G20, is it the same as the one they installed in the caprice with 350 TBI?

Does the Wiring Hanress and ECM from the g20 fit in the Caprice? Or do i have buy a painless wiring harness? If, what Ordering Number is the right one, for this Engine?

regards

[ASJT3]

Looks like no one ever replied to this thread.... I am thinking about doing the same thing. My baby finally died My '87 Caprice 307 wagon blew some sort of rod bearing, still haven't been able to take a look yet. anyway I'm planning on throwing in either a 305 TBI or 350 TBI similar to my '90 C1500. Any advice? Will the TH200R4 bolt up?

Much thanks,

alex

[silicon212]

You're probably better off putting a carb intake on that 305/350 and using the carb you have. TBI uses an electric fuel pump with a 9-12 PSI pressure level. The carb uses a mechanical fuel pump. Which leads to another point - a TBI SBC block from a truck may not even have a mechanical fuel pump provision on it.

At the very least, you'd need a complete computer/harness swap, to use the EFI.

The TH2004R will bolt to an SBC engine with no prob - they all have a dual pattern engine flange - but it might not live long behind a 350.

[ASJT3]

Originally Posted by silicon212

You're probably better off putting a carb intake on that 305/350 and using the carb you have. TBI uses an electric fuel pump with a 9-12 PSI pressure level. The carb uses a mechanical fuel pump. Which leads to another point - a TBI SBC block from a truck may not even have a mechanical fuel pump provision on it.

Ya I would probably would pull a fuel sending unit from a junkyard Caprice.

Originally Posted by silicon212

At the very least, you'd need a complete computer/harness swap, to use the EFI.

Yep I figured as much.

Originally Posted by silicon212

The TH2004R will bolt to an SBC engine with no prob - they all have a dual pattern engine flange - but it might not live long behind a 350.

Ok got it, so it would destroy the 200R4 huh?

[j cAT]

Originally Posted by ASJT3

Looks like no one ever replied to this thread.... I am thinking about doing the same thing. My baby finally died My '87 Caprice 307 wagon blew some sort of rod bearing, still haven't been able to take a look yet. anyway I'm planning on throwing in either a 305 TBI or 350 TBI similar to my '90 C1500. Any advice? Will the TH200R4 bolt up?

Much thanks,

alex

I would see the cost to repair the 307 engine. then if possilble get another 307 if the body shape justifies it.

305/307 are very different engines. I like the 307 much more than the 305. better design, less issues.

how many miles on it when it blew up ?

[Blue Bowtie]

ASJ - Silicon is correct about a stock TH200 for that vintage. However, if you really want to keep the trans it can be modified to survive behind a fairly healthy 350 in a heavy car. It may or may not be worth your time and effort if you can get a complete drivetrain from a donor car, however.

If you go to a TBI you will need the wire harness from the C200 connector and ECM all the way to the front, including the relays and sensors, or will have to modify the existing harness. You may also need to add an auxiliary fuse panel alongside the main fuse panel.

Another option for the fuel source on a TBI (or even TPI/LT1 at 45 PSI) is an external pump, but they tend to get a bit noisy.

IMHO, the Olds 307 has outlived its useful life and if you replace it the SBC is a better choice. If you want reasons, start pricing the replacement crank kit, pistons and rings, shop work, and ancillary parts for rebuilding the 307. IF you can even find them, you would probably spend more than a compete, new crate engine just to have the same "mighty" 307 you once enjoyed. There are plenty of quarter-million (and higher) mile SBCs out there testifying to the durability of the design. Just make sure you go with a roller cam design regardless of the make.

[ASJT3]

Originally Posted by j cAT

I would see the cost to repair the 307 engine. then if possilble get another 307 if the body shape justifies it.

305/307 are very different engines. I like the 307 much more than the 305. better design, less issues.

how many miles on it when it blew up ?

Truthfully, I really haven't had that many problems with the 307....but it's a SLUG!!! The 305 TBI on my 90 C1500 is worlds faster....I want it lol. So i figure either a 305 or 350 TBI would be a good fit?

The 307 had 180,000 miles on it. I believe the problem stemmed from lack of oil. The car consumed about a quart per 100 miles, if you can believe it. When my brother drove it up to pennsylvania it crapped out. A friend mechanic took a look at it up there and said something about a melted bearing. I haven't been able to take a look at it yet but figure it's probably a good time to go ahead and do what I've wanted to for a while - change the engine.

What do you think? The 307 had way too many vacuum lines etc. The 305 in my truck just seems a whole lot simpler.

[j cAT]

Originally Posted by ASJT3

Truthfully, I really haven't had that many problems with the 307....but it's a SLUG!!! The 305 TBI on my 90 C1500 is worlds faster....I want it lol. So i figure either a 305 or 350 TBI would be a good fit?

The 307 had 180,000 miles on it. I believe the problem stemmed from lack of oil. The car consumed about a quart per 100 miles, if you can believe it. When my brother drove it up to pennsylvania it crapped out. A friend mechanic took a look at it up there and said something about a melted bearing. I haven't been able to take a look at it yet but figure it's probably a good time to go ahead and do what I've wanted to for a while - change the engine.

What do you think? The 307 had way too many vacuum lines etc. The 305 in my truck just seems a whole lot simpler.

with that amount of oil consumption I believe you that the 305cu has more power. I know of many with the 307cu that have gone over the 2oo,ooomi and thats will no oil burning. 307 has more torque. lower RPM and its smoother / better drivetrain match.

the 307cu thats in there is junk. not sure about parts /engine if its available . check the local scrap yards . this engine was used in many GM vehicles including caddy's.

[ASJT3]

Originally Posted by j cAT

with that amount of oil consumption I believe you that the 305cu has more power. I know of many with the 307cu that have gone over the 2oo,ooomi and thats will no oil burning. 307 has more torque. lower RPM and its smoother / better drivetrain match.

the 307cu thats in there is junk. not sure about parts /engine if its available . check the local scrap yards . this engine was used in many GM vehicles including caddy's.

Yeah, I've seen plenty of 307s at the junk yard. Maybe I should go with a replacement just to save some time.

[j cAT]

Originally Posted by ASJT3

Yeah, I've seen plenty of 307s at the junk yard. Maybe I should go with a replacement just to save some time.

you will save more than time. find one with not too many miles that looks like it was properly maintained. engine swap is easiest/cheapest/fast. if you install one in good shape you will see how well it works with the vehicle.

you last engine to get that bad my guess is cheap oil and fram oil filters. going over 4000 mi on cheap oil.

make sure the radiator is not corroded. use a 3 core.

install a transmission cooler also.