My 65 300 cid/st300. Just think'n ahead, can I bolt on a 3 or 4 speed tranny to my 300? I'd like to keep my 300 cruiser for a while, it's got plenty for freeways and still good on fuel but, man that drag 2 gear thing is holding me back. Would an ST400 be an easy bolts out/bolts in switch? Or some other idea. If so what can I pull from at the boneyard. Any ideas guys? thnx Nick
LUCKY DOG Nick: i'm fairly sure that your bellhousing bolt pattern matches v6/350 pattern , check and see about crank to flex match-up, starter and other areas but i think that might be "doable". that would be a great combo w/over-drive i think. a "friendly" salvage yard and a couple questions at a good tranny shop may help. Del
A 350 turbo is a straight bolt in, the short tail 400 would need to have the crossmember moved back and change the yoke. A 200-4r would also require the crossmember to be moved back, but would retain the same driveshaft yoke as what you have now. We di a swap on a 66 lark last year with a 300 engine and 300 trans , we first put in a 200-4r, then we took that out and put in a s-p 400. He likes the car MUCH better with the 400 s-p than he did with the 200-4r. Jim Burek
My next question then would be, if the 350 is a straight swap, what would be a good canidate as a donor? Is the 350T the same as any standard chevy? thanks, Nick
LUCKY DOG Nick: chevy-nope / b-o-p- yep , th350 or th400 way to go cheaper i think , th350 would be better there for a lower horsepower combo , the overdrives are more money but it depends on the driving you do also - if it involves alot of four-lane action then maybe the o-d money may be well spent - and also your long term goals for the car , the money you save by putting in a solid th350 could be well spent in other areas-? Del
Ok, so if the T350 is Buick only, then what would a good donor be? How can I tell exactly between the 350 and the 400? Any good links on this subject? And btw, I always heard Chevy used a T350. Is it the same in name only? Just curious. Of course as always this way ahead of where I am with my car now, I just try to do my homework ahead of time. thanks guys, Nick
The difference in the Chevy TH350 and the BOP TH 350 is the bolt pattern to the engine block. Chevys have a bolt at the top. HTH. Matt Gandenberger
Nick, the internal parts are the same between a Chevy and a B-O-P (that's Buick-Olds-Pontiac, all the same bellhousing pattern) turbo 350 trans. Yes there are some slight differences in that all T-350's are not exactly the same, but to generally answer your question, there is no strength difference in a Chevy vs B-O-P. It absolutely does not have to be a T-350 out of a Buick only. Easy ways to tell the difference between a T-350 and T-400. 1) T-350 has vacuum modulator on the side, T-400 has at the rear. 2) Pan shape, T-350 is mostly square, and T-400 is irregular shape (sorta kinda like shape of TX). 3) T-400 output shaft is bigger diam 4) T-400 is physically bigger around and weighs more. I think you should use a T-350, a T-400 will be overkill and not prvide any real benefit besides more installation hassles and takes more hp to run it. If you want an OD consider a 200R4, it's the only one available with a B-O-P pattern. All 700R4's are Chevy pattern only.
[1) T-350 has vacuum modulator on the side, T-400 has at the rear. The t-400 has the modulator on the side, the 350 is in the rear. Jim Burek
My memory failed me!!! Thanks Buick535 for clearing that up on the vacuum modulator location, I was going from memory and got them mixed up. For what it's worth for you racers looking for that little bit of advantage with your T-350. look for one from a small light car like Vega or Monza, they had the "lightweight T-350" that had the drilled drums and hollow output shafts with roller bearings instead of bushings. Less rotating weight and friction. You can see the hollow shaft at the end, but of course the drilled rums are inside and hid until teardown.
Ok, I'm starting to get the picture. To be clear, I'm trying to get better highway gear for road trip'n. The 2 speed st300 works fine around town but, higher speeds I really wish I could shift. I want to keep the 300cid motor so, I'd like the quickest/easiest, bolts out, bolts in sollution. So here's my next question's: If I go BOP T350, would it have the same STP kickdown set up as the st300? What car/cars would be good to pull from. thanks guys, Nick
The t-300 ises an electrical kickdown, the t-350 uses a cable kickdown. If you are looking for better mileage on the road, you won't have any improvement as the t-300 in high is 1to1 and the t-350 in high gear is also 1to1. This means there will be no difference on the highway with either one. Jim Burek P.A.E. ENTERPRISES
Buick535 is exactly correct, the highway cruising rpm is not going to change unless you put an overdrive trans in place of your old ST-300. So that means you need to look for a 200R4. Be aware that the 200R4 uses a throttle valve (TV) cable, which acts in place of the vacuum modulator and the kickdown. The TV cable must be hooked up correctly in order for the trans to shift right and long term reliability. It's not hard to do, but you must set it correctly.
Nick, here is something to think about. I dont know what car your working on but I have a 64 lesabre with the 300 4 barrell motor in it and it came with a super turbine 400 from the factory. I think alot of the bigger cars had this same engine/trans combo. this would be a direct bolt in to your motor. flex plate is the same as yours starter same, crossmember all the same. good luck and I hope this helps Tim.
hmmm...ST400. Is the 400 a 3 speed? Does it use the same (STP) set up for kickdown? Nick btw, It's a 65 Skylark 300 motor/st300 trans
overdrive transmission Hi Nick, there is an article in a magazine detailing the late model GM 4 speed overdrive swap into older GM compacts. (I think a it was a GTO) The conversion sounded straight forward and rewarded the owner with much better highway fuel mileage at lower rpm. It was posted to me by one of the buickperformance group users. I run a 4speed overdrive everyday driver and would love to have it in my 64 Buick. So before you decide to shove in the older 3 speed technology see if you can get hold of a copy. cheers
