olds to chevy swap

[brethenry_08]

ok so i have an 85 cutlass supreme brougham with the 307 in it.
i am wanting to do an engine swap to a 305(would be a 350 but a 305 for 75$ is way to cheaper) anyways the plan is to get the 305 rebuild it and up.
the only reason i am doing this is because it is so much easier adn cheaper to go with chevy than olds (very tight budget) so im wanting to get opinions on what to put in and on the 305? and yes i know that i need a chevy transmission planning on a turbo 400

thanks
Bret

 

[85 Cutlass Brougham]

Well, if it is cheap you want, why not an Olds 403? It would be cheaper than a 350 and not need a transmission. Plus, if cost is so much of an issue, why go with a TH40 or a 305? the TH400 is overkill for a 305, and the 305 will never make good power without lots of expensive work. By the time you spend all the money (read the sticky on the V6-V8 swap parts) needed to go Chevy, you could have had an Olds 350 or 403 instead. The Olds is cheaper initially, but since you want cheap as an end game strategy why not start with a dimensionally interchangeable engine?

 

[brethenry_08]

well all in all its has been a bit of a challenge for me to find a olds engine and it is already a bit difficult to find any performance parts for the 307 i have now. the turbo 400 i have found is only gonna cost me 50. yeah it is over kill but i dont want to have to worry about tearing it up with too much power when i get myself a larger engine (if possible im goin to get a 572 bbc)
and i dont really want to have to worry bout a transmission at that point.
but as far as engines go a 305 for only 75$ is really cheap and a lot easier to come up with than 500 for a 350(normal price in chattanooga)

 

[Vern]

85 Cuttys points are valid. All he is saying is look at the sticky about what you need to do for the conversion parts & labor to swap things over plus the cost of the 305 to just finding a 350 or 403 Olds and doing a direct drop in. Also consider looking a little bit longer term with regards to your goals if all you want is basic transportation to get from a to b the 305 might make sense but it sounds like your longer term goals are a lot bigger and its usually cheaper to do something right or at least better the first time then to do something twice. Also as time goes and you want to add some speed parts, headers, cam, intake etc is also out their for the Olds just not plastered all over jegs catalog but they have it and their are plenty of dedicated Olds vendors just search the web.

Pick the th400 up for the price just to have it. On a side note fwiw I picked up a running Cadillac 472/500 for free from a derby guy. Talk about an easy cheap 13 second ride and a crazy tire fryer. Back to doing a lil more work & expense with doing a conversion but at least its not for a 305. Their is still a lot of truth to the ole no replacement for displacement adage.

 

[brethenry_08]

i do understand what u are saying about the 305 it is not that big of a engine but they are a dime a dozen so you can get parts for them really cheap but yeah i think there is a 383 stroker a guy is tellin me about for like 150 pretty close to the 305 price so im gonna jump on that one instead of the 305

 

[85 Cutlass Brougham]

The displacement is not the issue with the 305, it's the bore size. You can't get big enough valves in a 2 valve head for that small bore. It is very limited in power potential. Now a engine with around 300ci is not a bad thing. A Chevy 302 is a great little engine, as is a Ford 302. However, both of them have 4 inch bores like a 327 or 350.

As for 307 Olds parts, it's an engine that no one really makes anything for. The 307 and 260 were the b*st*rd children of the Oldsmobile family, and use a unique head that isn't good for anything but scrap value. That's why nothing is available for them. However, the same cannot be said of the 330 and larger engines. Plenty is available for those engines. Olds V8's have the additional plus of using high nickel content iron for their blocks, which means they do not go through bore wear like a Chevy. it makes for a heavier engine, but it also means it will last longer.

As for the TH400, it uses a lot of power to drive it, so it is not really ideal for a small block car. However, if it is a short shaft Chevy TH400 (from a car) it is worth some cash. I'd buy it, sell it, and get an overdrive automatic instead.

I would also try to find a U pull it yard within 50 miles of where you live. Most of them are one price fits all of one type of part. That way, the engine from a Yugo is the same price as an Olds 455. The 455 is a bit of a stretch to find, but the Olds 350 was common in Cutlasses and large Olds barges of the 70's.

I will also say that there is nothing wrong with a Chevy, it's just not the best budget choice here. I like the Chevy 350 and used one to power my car. I also wrote the sticky on how to swap over to Chevy power because too many people don't realize just how many parts you need to make it work properly.

 

[Uncletruck]

I would listen to these guys. I'm doing the same sort of thing for my '78 LeMans that has Buick 231 V6. I bought a beautiful but wrecked low mileage '79 Delta '88 land barge with Olds 350 and TH400 last year for $150.00. I sold the transmission and a multitude of other good parts and made enough money to pay for the Delta, a new radiator, engine mounts, water pump, alternator, and seals and gaskets- basically everything I need to put the enigne and a BPO TH350 I had hanging around in to the LeMans. Then the scrapyard came and hauled away the Delta for free. I'm being paid to swap my old V6 now, with it's core worth a few bucks too I'm sure

If you have a good BPO transmission on the car and are on a budget, it's going to be way cheaper to put an Olds 350 or 403 engine in than switch everything over to use a SBC. A Chevy 305 and TH400 would be a counterproductive combo in a G body. Bolting a 403 in place of the 307 will give you all that extra gain in power and torque without adding any weight, plus your 307 is probably paired to a 200R4, so you get the overdrive advantage for better MPG.

-UT-

 

[Blake442]

What transmission does your car have in it currently? The 200-4R that you probably have has a dual bolt pattern bellhousing that will accomodate either Chevy or BOP engines. Some TH-350's even have the dual pattern bellhousing.

You think a 305 is poochy now, try putting a TH400 behind it...with the parasitic power loss you'd probably only be putting like 75 hp to the wheels...weak!

What's wrong with your current 307? If you hope to put in a crazy BBC someday, and your 307 is fine, why not just leave it in there and save your pennies for the BBC? It's easy to get side tracked, I know from experience.
I can't help but follow that old sayin... if it ain't broke, don't fix it!

 

[crappycutlass]

http://www.goingfaster.com/spo/carcraft325hp305.html

i dont agree with all of it but yea...


also these guys are right about the th400 behind a 305..
200r4's arnt that bad IMO

 

[brethenry_08]

well i do appreciate every ones opinion on this subjuect and am now convinced to get a 350 old or a 403 nut out of curiosity what was the 403 olds most common in? sorry i dont have a very large knowledge on oldsmobile i used to be more into imports than anything and some chevy but tthats about all i have ever messed with