Out with the 260 in with the 350

[olds307 and 403]

When your TH200 dies, which they usually do, seriously consider a mild built TH2004R trans. They are a direct swap, except frame extensions are needed but readily available. With the lock up torque converter and a .67 OD gear, the 2004R drops rpm by 1000 rpm over your 3 spd. Then you swap in a 3.42 or 3.73 posi and gain a ton of performance without affecting highway mileage. Is it a total rebuild on the Olds 350? What big number is by the #1 and #8 spark plugs? Flat top pistons and a bowl hog under the exhaust valves are needed for a 73 350 to equal earlier motors, power wise.

 

[carnutjw]

As far as your trim pieces= put an Ad with pictures in the wanted section of the Classifieds- bottom of main page.

 

[Cutlass 3:16]

Don't do 3.73 if you ever want to go on the highway. 3.42 is even too much. 3.23 or 3.08...

I appreciate that heads up!

 

[Cutlass 3:16]

As far as your trim pieces= put an Ad with pictures in the wanted section of the Classifieds- bottom of main page.

Thanks bro!

 

[Cutlass 3:16]

When your TH200 dies, which they usually do, seriously consider a mild built TH2004R trans. They are a direct swap, except frame extensions are needed but readily available. With the lock up torque converter and a .67 OD gear, the 2004R drops rpm by 1000 rpm over your 3 spd. Then you swap in a 3.42 or 3.73 posi and gain a ton of performance without affecting highway mileage. Is it a total rebuild on the Olds 350? What big number is by the #1 and #8 spark plugs? Flat top pistons and a bowl hog under the exhaust valves are needed for a 73 350 to equal earlier motors, power wise.

Man, I love the info you are providing. I'm taking notes and will let you know what those numbers are near the 1&8 spark plugs. I got the 350 off craigslist but i'm still in contact with the owner. He told me he didn't make any upgrades to the motor besides replacing the original parts. Those motor mods could give me exactly what I want performance wise. Like you mentioned earlier.. when I'm on the highway she's working hard.. that transmission upgrade would be ideal. Now i just need to prioritize this list and explain this to my wife haha..

 

[dr78442]

Very nice. I love the 78-80 cutlass. I like the direction your heading in

 

[DRIVEN]

I'd really recommend playing with a gear calculator. My '79 had 2.29s originally. I found that a 200-4r and 3.42s gave me the same cruise RPM. It felt like a 100hp bolt-on and the MPGs stayed exactly the same.

Congrats on the new engine. Looks great!

 

[JAMCAR223]

Nice looking motor. Couple of questions...
- I'm curious about the hood clearance with the RPM manifold and 14x3 air cleaner?
- Does the spark plug wire looms hit the AC housing?
Thanks!

 

[olds307 and 403]

The reason I ask about the number on the head, is chamber size. It looks like a 7A head which would make it a 72 motor. If cast replacement pistons were used, you will be around 8 to 1, like stock. Those same pistons would give 7 to 1 with 73 350. The early 350 heads are 68 to 70cc stock. The #8 heads used on 73 to 76 motors had 77 to 78cc chambers.