305. Swap

[64nailhead]

I would be looking for an overdrive trans if I am starting from scratch.

I agree. But I thought of what was the reason to swap in a 305? I assumed, which could be incorrect, that it was for budgetary reasons. That implied to me that the OP wouldn’t be up for a trans install and gear swap needed for an OD trans.

I should’ve asked though. Roxanna, what’s your budget and intended use for your car?

 

[pontiac guy]

Where in TX are you? Why a 305?

 

[olds307 and 403]

Do you have the motor mounts, frame mounts and all the accessories for the 305? None off the 260 will work, only thing that will swap is the distributor cap. A 80 to 84 Olds 307 is very comparable to any stock 305 in the power department. Even a 85 to 90 swirl port 307 is a 35 hp gain and 50 ft/lbs of torque over your 260. The reason a TH2004R is a good trans choice is two fold, a lower first gear and a .67 overdrive gear. With the lock up torque converter engaged, it drops highway rpm by 1000 rpm. That means either 3.42 or 3.73 gears can be installed and even the basic torque converter stalls around 1900 rpm, compared to 1600 rpm on a stock TH350. All combine for much better acceleration, highway manners and mileage.