LoganMiller68

Hey All!

Currently my 68 442 has a 400 BB with a TH350 behind it. I'm in the process of redoing this car and to save the #'s matching 400 motor I'm building a 455 to drop into the car.

Now I've run into a decision that I was wondering if you all could help me with.

I know that the TH350 will not stand up behind the 455, especially after I build it up. So my plan is to rebuild a TH400 to go behind that. Is this a good choice? Or should I say, is this the BEST choice? And what should I know before I go into this? Any upgrades to the TH400 I should do?

I also am thinking of maybe doing a manual transmission conversion on my car sine it already has the spot for the floor shifter cut out and I would have to do to much modifications. What do you guys think?

Sorry about all the questions This is the first time that I will be doing a project this extensive and I want to make sure I get everything right!

Rickman48

I'd have thought your original trans was a 400 - where'd that go?
When I did a 400, I used a B+M valve body, adjustable modulator, governor weight kit, deep pan and 'Holeshot' converter - worked for me!
Put it in a wagon that was a 4-speed car, as I was tired of blowing transmissions - 4 Muncies and a Saginaw!
Olds clutch set-ups are a PIA to find!

LoganMiller68

Ya, I thought it would have too! haha but I have no idea were the original TH400 is so now I'm stuck with having to rebuild one. How much HP were you putting through that transmission in your wagon?

That's a lot of Transmissions!

You mean for doing a manual setup right? Hmmm

Rickman48

Wagon ran a best of 13:53 @ 110MPH w/ a 3:55 posi - stock convertor!
The Holeshot really 'woke it up'!
Never ran it with the Holeshot, but got a V8 Vega running 12:70's by about 5 lengths, once in!
Figure 375 horse to the rear wheels!
Once you've had a M-22, the others don't hold-up to powershifting!

LoganMiller68

Wow, now that's a power wagon!
Were you running the Vega with the TH400?

507OLDS

A TH350 will handle the 455 just fine,if it's built right.My friend has had one in his 71 442 for 12 years now,and that car runs 11:70's all day.He took his original 455/TH400 & parked them in the corner.He didn't have another TH400,and we've had good success with a TH350,so he had one built.
Yes,your car should have a TH400,and you could still go that route,if you can find one.I have 2 of them,already rebuilt & ready to run.If you do decide to swap to the TH400,you will need to shorten your driveshaft about an inch,and get the TH400 yoke.
If you decide to convert your car to a stick-shift,then make sure you have your 455 crank drilled for a pilot bearing,as they did not all come drilled for one.This is something you would want to do with the crank out of the engine.

LoganMiller68

Hows your friends 350 built? Like aftermarket parts etc. The last thing I want to do is destroy this TH350 I have when it gets behind the 455. I also don't feel like modifying this drive shaft I have now. So staying with the TH350 would be my choice, especially because building up that TH350 more would be less of a hassle then putting in a TH400.

507OLDS

Any idea what year your TH350 is? Any idea how much power you plan on making with your 455?

Some blue clutches & a Trans-Go stage 2 shift kit are a good start.If I had more info,we could get into picking a converter,and any other pieces you might need.

LoganMiller68

Thanks four your help so far! When I get outta work today I'll look up the number on my trans and figure out its year and we can go from there if you'd like.

As far as the 455, as much as I can get out of it. i don't think I'll hit 500hp but anywhere between 400hp and 500hp

507OLDS

It's really not the HP that breaks the transmission.It's the blunt force that is thrown at it,like torque,trans-brake,slicks,clutch,etc.You'll be fine with a good TH350,and your car is already set-up for it.

LoganMiller68

Awesoem! ok, well when I get a chance tonight I will figure out the year of my trans and we can go from there on parts I should get. Thanks!