Oldsboi

I'm new here and i was looking for some help with an engine swap. I have a 1988 Oldsmobile custom cruiser with a 307 V8 and a TH200-4R transmission. I wanted to swap the engine originally with an olds 350 however I was doing some reserch on the transmission and i belive it can bolt on to a Chevy BOP or a cadillac engine. So I belive I could put a Chevy 350 in the Wagon. I think it's easier to get a hold on a Chevy 350. So my question is should i find an olds 350 or should I get a Chevy 350 and would i need to swap the transmission also?

CRUZN 66

Welcome to the group... Recommend you stay with an Olds 350... It's a simpler conversion... Direct bolt in without having to change engine/frame mounts, exhaust, some wiring etc...

Oldsboi

Ok thank you do you know where I could find one that's not crazy expensive.

Olds64

x2

An Olds 350 would be a direct swap for your 307.

Where are you located?

Oldsboi

I'm in Rhode Island.

Olds64

Here's an Olds 350 for sale near you:

https://providence.craigslist.org/pt...412247717.html

I don't know anything about this engine, just located it with a quick search. It would at least be worth a look.

Oldsboi

Thank you for the help that looks good it will just be a little while until I can get it I'm fixing up an Audi A6 to sell right now. With a 350 I wouldn't need to swap the transmission right?

Olds64

The 200 4R would mate to an Olds 350 just fine. I've heard guys say that they run a 200 4R behind a 455 and make it work by granny driving it all the time. Of course, this could be one of those "it was this BIG" stories. I wouldn't hesitate to use a 200 4R with an Olds 350. You should at least replace the transmission filter and flush the fluid though.

Oldsboi

yeah i was planning on doing that maybe even a rebuild kit.

olds 307 and 403

I would assume that is a 9 to 1 Olds 350, if stock inside. You could bolt on your stock carb and distributor but you would need a Performer intake, not the RPM, as you would need to run EGR with the stock computer. A good shift kit like the CK or big Transgo kit is a good idea to help your 2004R live.

Oldcoyote

Also if the 307 is in good shape, consider changing the rear end to a 3.90 .Just right for those tires. I did that on my wagon.

Oldsboi

MY local junk yard has an olds 350 they just need to check if it runs (probably to charge me more lol). I also want to rebuild the engine. Put some performance parts in it.

olds 307 and 403

Just make sure it isn't a 1977 to 1980 Olds 350. Check for 3A heads, which are crack prone and terrible flowing along with a windowed main bearing block. It is the worst of both worlds. I could have bought a pair of them for probably $100 plus gas but passed on them.

Oldsboi

Why cant it be a 1977 to 1980?

olds 307 and 403

The block is weaker and the heads flow poorly on the exhaust side and have a tendency to crack. It can be used but needs better heads and a girdle if you want to rev it up. In stock form it was only 160 hp and 265 ft/lbs of torque. The 79 and 80 Hurst/Olds 442 had better exhaust so it had 170 hp and 275 ft/lbs.

Oldsboi

I was probably going to change the heads on whatever I got anyway and i didn't know what a girdle was so i had to look it up i might put on in just to be safe or should I not as long as it's not in that year range.

Olds64

There is no reason for you to buy and install a girdle. You're not planning on racing your OCC, are you?

Oldsboi

no, no racing I want to keep it pretty mild I'm using it as a daily driver now and after the swap.

Oldsboi

what is the stock ratio?

Oldcoyote

I believe the stock ratio was 2.93 . It's been a while .The change was quite dramatic. You can still do the engine later .
On my 88 Cutlass I used a 3.73 because of the smaller tires. Just my opinion .

olds 307 and 403

A one to one ratio gear change will make a huge difference, even the 307 would feel decent. Here is a calculator, it is set up for a 2004R with lock up converter and is very accurate. It depends on tire size and what speed you drive on the highway.http://tech.oldsgmail.com/ch_axle.php
A girdle is not necessary on a 76 and earlier block. A girdle is good for the 77-80 350 if you push higher rpm's. Lighter forged pistons and proper balancing should help a lot.

Olds64

I have to disagree. If the OP wants to install an aftermarket intake, a hotter camshaft, headers and even upgraded internals (i.e. forged pistons and a HV oil pump) there is NO need for a girdle (even if it's a 77-80 SBO).

joe_padavano

Come on people. This is a Custom Cruiser, not a W-31 drag car. ANY 1968-1980 Olds 350 block will be fine. A girdle is NOT required for the OP's intended use. The block will not crack. Aftermarket intakes will be fine. This engine is rarely likely to see more than 3500 RPM. Let's not go crazy here.

olds 307 and 403

I agree Joe, if he stays 5000 RPM and under, it will run forever. The factory shift points should be 4000 RPM full throttle max. I was just informing him on the less desirable 77 to 80 350. The block is not the only issue with them, the heads suck and are crack prone. I don't think the issue is a severe as the Dodge Magnum heads. Mine gave out an hour from home, pressurized the radiator bad, no fun at all. I towed it home with my 70 Cutlass, which must have looked really funny.

Oldsboi

Idk the way I drive the RPM might get very high lol. I'm just kidding I'm not going to make it to crazy it is a daily driver and MPG is bad enough as it is. I will change the heads regardless of the year and if i get new pistons I might get the cylinders machined a little and get bigger pistons.

Oldsboi

The 307 has an oil leak and is burning oil. I'm sure it's an easy enough fix but i just want an excuse for a bigger engine.

Oldcoyote

My 307 started burning lots of oil. So I rebuilt a 403 and put it in the wagon . Still liked the 3.90. It's not the lightest vehicle around.

Oldsboi

no it's definitly not light at all. So the 3.90 would give me more torque at the wheels right?

Oldcoyote

Lots more. It's also a good time to add a posi so as to maximize expenditures .
And while you're under there, how about a rear stabilizer bar . You did put a larger one on the front right?
And don't forget cargo coil rear springs.
And, and, and........

Oldsboi

I know there's so much to do but I'm going to get a project car so i can go crazy on that. The person that had the Wagon before me used it for towing so it does have air shocks and i wanted to put coil overs in the front and rear. Because the suspension is shot.

Oldcoyote

I did all those things to my 89 Olds wagon..

My life is dedicated to proving that:
You CAN polish a tur_.

olds 307 and 403

Unless you buy aluminum heads which are designed for the BBO and need an electric fuel pump, you need to have whatever 350 you find heads or another set rebuilt. The Procomp aluminum heads are decent with better combustion chambers and flow. But they need different valves and springs as out of box, assembled heads have issues. Also the end of head hangs over meaning a mechanical fuel pump won't fit. Also they have large chambers and that means 9 to 1 compression at most even with flat top pistons, without milling with a 350. That is why I say a 73 to 76 350 is a good motor, being smog motors they are usually good shape inside and cheap to buy. With flat top pistons, gives around 9 to 1 and a bowl hog under the exhaust valves puts the factory #8 heads on par with early heads. Also with Mahle's new 10cc piston, brought to the market by Cutlassefi, that 68 motor on Craigslist can have nice daily driver low 9 to 1 compression with early 350 heads.