butchashop

well now that i have the 425 running and tuned correctly I have been driving it everyday for 3 weeks and all seems good except the stock tranny seems like its just not geared good enough for the big block I'm currently usung the stock tarnny that was bolted to the orig 330 the car actually feels like the trany is holding it back? I'm looking to see what my other options are and what will fit up to the 425 and hopefully not require and drive shaft modifications.. does such a tranny exsist? hase anyone used a th350 they seem pretty cheap and easy to com by thanks in advance

joe_padavano

You are correct. The stock ST300 trans in your car is only a two speed. The 1.76:1 first will hinder acceleration as compared to the lower first gear in a three speed or four speed automatic. The TH350 is as close to a total bolt-in as you could find. The only issues are the need to connect the kickdown cable to your carb and the fact that your two speed shifter won't let you manually access low in the three speed trans. The TH350 would need a minor beef-up to live reliably behind the 455. The TH400 and 200-4R both require slightly more work to fit. The main difference is the crossmember location. Moving the crossmember also requires the e-brake cable to be changed. On the TH400 you also need a shorter driveshaft and new front yoke.

butchashop

so the th350 will work with my exsisiting drive shaft and cross member location? and is there a difference between a th350 off a chevy and a th350 off and olds as far as bolting to the block is concerned or are the th350 bolt patterns all the same i can find them for sale cheap but i dont want to buy one have it re-built and find out it doesnt bolt up I would probably loose it at that point

jensenracing77

the Chevy will not work. it will have to be a olds, buick, or pontiac.

butchashop

thanks!! i appriciate all the help i found a guy with one out of a 70 skylark for 100 bucks and he gaurentees it to run perfect I also must add this is absolutley the best site with the best people its been a struggle ironing out the bumps in my f85 and i couldnt have done it without the help from you guys thanks again

Oldsguy

That is nice of you to say so. It is a group effort and every member should take credit. I am glad that Joe has offered you some help as he is one of our most knowledgeable guys for across the board information on Oldsmobile. I hope you get yourself that TH350 and get it installed without too much trouble. If I haven't said so before, welcome to CO.

butchashop

thanks oldsguy, I ended up picking up the tranny and i will be throwing it in this week end but it must have been perfect timing because yesterday after noon i was heading home and as i turned onto my street the tranny slipped a little bit. so i guess its good that i bought the th350, so now im wondering if anyone has any photos of the the linkage attaching the kickdown cable to the carb? I'm running an edlebrock 600 and trying to get an idea of how to make up some brackets

olds425

I would like to add there are adapters to use the Chevy trans. I think Edelbrock and Lokar among others sell parts to add to adapt your kickdown.

Olds64

Here is a universal B&M throttle valve cable for the TH 350. You will need to buy something like this if the transmission you bought didn't include the throttle valve cable.

http://www.summitracing.com/parts/BMM-30287/