1985 Olds 442, 307 to Chevy350/th350 combo

[442force]

Looking for info on swapping out my 1985 442 ,307 to a chevy 350/th350 combo

I already have the machine work and everything built for the Chevy 350 so buying an olds block is not an option

I would like to run solid motor mounts if possible

Is there a topic sticky on this swap , Im sure im not the first. I searched for some time and lead me with no 100% answers

So if anyone has the Time to explain to me . What i need to put me in the correct direction . It would be greatly appreciated..

Thanks Erik O

 

[Vern]

You would be a real popular guy on oldspower or realoldspower. :lol: You might not find a buyer for that vin9 307 but lots of people would like to have that desireable KZ code 200-4r. Surprised with gas prices that you are going back to a th350 but maybe your going for more of a drag car than a driver, or maybe you just have one ready to go and the 200-4r needs a rebuild. The info you look for is in a sticky. If you are swaping chevy wheels on the Olds wheels would also be easy to sell on the forementioned boards. Wonder if anybody has ever taken a MCSS and swapped in an Olds 350 mostly just for the fun of heckling the blue bloods.🙂

 

[442force]

442

that transmission is that desirable.

Im foolish i supposed i thought it would be a paper weight.

thanks for the info.

any other ideas

 

[Vern]

I don't know about being "that" desireable as in worth a lot of money but it did have a special servo, a 400 rpm higher wot shift point, a factory shift kit, is able to shift into OD at wot etc all things a regular 200-4r could not. In like condition it would be worth a little more money than the th350 which is definately a good reliable transmission btw plus being a lot more desireable as a street strip transmission for the benefits of being more efficient, ie less power loss & better mileage, benefits of the lock up converter, reduced cruise rpm. Assuming the two are driveing the same rear end/gears the OD should get 33% better mileage plus another 1 mpg for the lock up converter. So if you would have gotten 12mpg now you can get 17mpg ie every time you would have spent $100 on gas you now only spend $70.

With regards to the converter if you cam your engine to make more power it moves the power up the rpm range so you get to where you benefit from haveing higher stall to get the car in its powerband for maximum use of its gearing & acceleration. The downside is a higher stall converter slips more before it engages waisting fuel each time you accelerate and especially if the stall is above cruise rpm where its slips going down the road. Not to mention the extra heat this puts in everything. The lock up converter if its say a high stall of say 3,000 only sees that slip under heavy load like at wot as it locks up under cruise. So you don't even notice the high stall except at wot ie much more efficient at part throttle & cruise no heat big improvement for a hot street car.

Last and probably most import benefit especially to the big block guys is you can run your 1/4 mile gears down the highway without buzzing your motor to high rpms. High performance engine rebuilds are expensive. The downside being the 200-4r costs more for a high performance build and is more difficult as in it takes more specialized parts and skills to build it up.

 

[85 Cutlass Brougham]

Yeah, I have been looking for one of those 442 TH 200 4R's for years now with no luck. Many of us on here swear by that trans when it is built properly. There are several 9 and 10 second GN's out there with it, so there really is no reason to change it. As for the swap, read the two stickies at the top of the page related to the V6-350 swap. It's about the same thing except you don't need the transmission. May I also suggest an Olds 350 as an alternative? It is a lot less work, and won't screw up the value of such a rare car as much as changing families. You can even keep the stock look under the hood, while only changing the one thing that is bad about the 442 G body, the 307.

 

[Vern]

I bought my GN brand new so I am well acclimated to the transmission. I even had a street strip build done for the one in my 442 with the billet drum/shaft so that it would hold up to the 570 foot pounds of torque put out by my Cad 509. I love this transmission for a relatively light high performance street car application. That said for a 10 second drag car that won't see much if any interstate driveing I would use a th400 or maybe th350 depending. I also would likey keep the sbc for another application and use an Olds 350/403 as 85 Cuttly suggests as their is several real benefits to staying small block Olds aside from cosmetic & resale value/market. He is not anti sbc or overly brand loyal either as he put a sbc in his regular Cutlass. Obviously I am not overly brand loyal either as I put a Cadillac motor in mine but with good reason and the 307 can always go back in and I can hook up the AC etc without anyone knowing anything different was there.

 

[85 Cutlass Brougham]

Nope, not against the SBC at all. I actually wrote one of the stickies on how to swap from a V6 to a SBC!. I like the ease and cheapness with which you can modify them, and the wealth of data that is available. I just would not put one in a low production Cutlass 442 when there is another option that would work well for little cash.

 

[dan2286]

I would definately agree on an Olds motor too. Sell the sbc, and buy an Olds 350. Maybe someone on this site might want to buy it. Also you will love the torque that the Olds engines can put out!!