Chevy 350 or 305

[1985Diablo]

elynn123 started all this, so I hope the info is helpful.

kingcolbert83 has it right. Just want to build the 305 I have.
Sure i could go out and get a 350 roller, but why when I already have a good block bored .020 over, heads 081's, crank, and the dubble roller is already on it. AND IT WAS FREE

elynn123 has a good (I think) 305 as well and was just looking for a little more from it, so why not build what you have?

 

[kingcolbert83]

elynn123 started all this, so I hope the info is helpful.

kingcolbert83 has it right. Just want to build the 305 I have.
Sure i could go out and get a 350 roller, but why when I already have a good block bored .020 over, heads 081's, crank, and the dubble roller is already on it. AND IT WAS FREE

elynn123 has a good (I think) 305 as well and was just looking for a little more from it, so why not build what you have?

If you already got all the machine work done then I would roll with the 305. I see no reason to get rid of a good running motor. Now if yours was on the brink then that would be different.

 

[custom442]

Yea i agree with the rpm. But I think he can be happy with the 305 and then build his 350 block to a stroker and swap everything over.

That's the best way to go if he's already got the 305.

 

[pontiacgp]

:?

 

[kingcolbert83]

Whats gets me is people put the 305 heads on the 350 to get more torque but they are so called junk.

some did do that and in theory it sounds good....and it wasn't for more torque...it was for higher compression because of the smaller combustion chambers on the 350 heads...oh and it didn't work as planned....


but if our going to build a 305 then more power to ya and I honestly hope you get the hp your expecting...

o ok. I had it backwards. So somebody tell me what is the problem with a th250 transmission? I posted a topic about this but got no responses. The th250 and th350 are the same except for the adjustment of the second band on the th250. Stock vs stock a th350 is better because it used better parts from the factory. But if both where built using the same parts of same quality then why wouldnt the th250 be able to handle any power?

 

[custom442]

They weren't the same internals, the th350 is stronger. The th250 is outdated and you'll have a hard time finding someone who'll waste their time rebuilding one. You can find nice used th350's for cheaper than building a worn out th250

 

[kingcolbert83]

They weren't the same internals, the th350 is stronger. The th250 is outdated and you'll have a hard time finding someone who'll waste their time rebuilding one. You can find nice used th350's for cheaper than building a worn out th250

The two transmission used the same internals. I have a th250 already and dont see reasoning to go buy a th350 trans when I can get a kit for the th250 and rebuild it. If you buy a kit for a th350 it says th250/th350 on the kit.

A derivative, the THM250, was introduced in 1974 in Chevrolets as a Powerglide replacement. Internally, the THM250 is a THM350 without the intermediate clutch pack with a band adjuster similar to the Powerglide. It was later reintroduced in 1979 as the THM250-C in the wake of the failure-prone THM200/200C.

I got the last paragraph from wikipedia.
http://en.wikipedia.org/wiki/Turbo-Hydramatic#THM350

 

[custom442]

Okay, I don't care where you got them. I had a th250 about a year ago and was looking into a rebuild. I asked about half dozen trans. shops and all of them said it was outdated and not the same internals as a th350. It would also cost more to rebuild.

And they were 110% right. I found a built th350 from a g body running high 10's low 11's for 550$. It would've costed me over that amount to rebuild the th250 to stock condition.

Look man, you've gotta look at what works, go read books, see what people have done already. No use reinventing the wheel unless you have deep pockets

 

[kingcolbert83]

Okay, I don't care where you got them. I had a th250 about a year ago and was looking into a rebuild. I asked about half dozen trans. shops and all of them said it was outdated and not the same internals as a th350. It would also cost more to rebuild.

And they were 110% right. I found a built th350 from a g body running high 10's low 11's for 550$. It would've costed me over that amount to rebuild the th250 to stock condition.

Look man, you've gotta look at what works, go read books, see what people have done already. No use reinventing the wheel unless you have deep pockets

The only difference is the adjustment band on the th250. Im not knocking what you've been told but how is the th250 outdated when both emerged round the same time. I have personally tore down and rebuilt both and it was a few parts that was diff. Why would it cost more when the kit is the same for both? Just some parts will be used and some wont.

 

[custom442]

okay, I'm not telling you not to do it. But when 6 people who make a living doing this tell me the same thing, there might be something to that :idea: