350ci question

le_sabre · 12-07-2005, 02:15 AM

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Hi guys , i have a 68 Le-sabre conv which at some point in it's life has had a 69 400ci installed. The 400 has been playing up so i'm looking at replacing it but with an original size 350. I may have the chance of a good 350 out of a 1973 Apollo, my question is , is the 68 350 and the 73 350 the same ? and therefore will it fit ( with the 68 original mounts etc ) back into my Le-Sabre ?

**Dr. Frankenbuick** · 12-07-2005, 03:30 AM

A Buick 350 is a Buick 350. Any will fit in place of the other. However, the 400 used different motor mounts and frame pads. Are you sure it is a 400? The LeSabre 400 package was referring to the car having an ST 400 transmission instead of the ST 300 transmission.

**bob k. mando** · 12-07-2005, 11:53 AM

you might want to try hook up a restorer with that 400. the 400ci big block was the largest engine buick offered in the mid-size cars.

le_sabre · 12-09-2005, 01:10 AM

Thanks for the replies, yeah i'm sure it's a 400 with a Th400 boxi've had it checked over by a local specialist ( i'm in the UK by the way).
So it sound like as long as i get the original engine mounts it will fit back in ok which is nice to know.
Can you tell me what gearbox the 68 Le-Sabre ( with a 350ci) came with as standard.

**bob k. mando** · 12-11-2005, 10:30 PM

Can you tell me what gearbox the 68 Le-Sabre ( with a 350ci) came with as standard.

can't say for certain, but GM normally mated 350cu in engines up to TH-350 automatics. the TH-400s usually didn't get put in a car unless it had a big block.

the TH-400 WILL bolt up to the buick 350 engine though. the extra overall weight and rotating mass will slow you down relative to a TH-350 but a TH-400 in this application will be bullet proof as long as it's in good repair.

http://www.442.com/oldsfaq/oftrn.htm...n%20Comparison
something else, while the same externally the same the 73 engine is going to be down on compression and power compared to the 68. if you want to build the 73 to 68 specs you can.

**Dr. Frankenbuick** · 12-16-2005, 04:54 AM

Originally Posted by le_sabre

Thanks for the replies, yeah i'm sure it's a 400 with a Th400 boxi've had it checked over by a local specialist ( i'm in the UK by the way).
So it sound like as long as i get the original engine mounts it will fit back in ok which is nice to know.
Can you tell me what gearbox the 68 Le-Sabre ( with a 350ci) came with as standard.

You will also need the frame pads that receive the motor mounts. Buick used different frame pads and motor mounts for the 350 and 400 engines.

The 68 LeSabre came with a ST 300 two speed automatic transmission in the base model. The LeSabre 400 had the ST 400 three speed automatic transmission. A three speed manual transmission was also available. The 350 was the only engine available in the LeSabre, and the standard rear gear ratio was 2.93 for the automatic LeSabre and 3.23 for manual LeSabre.

**regal1973** · 12-16-2005, 11:49 PM

I cracked a head on my 73 350 mtr & 350 buick heads are very thin on the ground in Australia. I located a 68 350 buick mtr & found that everything is the same exept the water holes on the 68 were tiny round ones while the 73 were larger oblong.
The 68 mtrs oil through the rockers while the 73 oiled topend through lifters & pushrods. While looking at the two mtrs the only thing I think you cannot do is use the rocker gear & 70 model on heads on the 68-69 mtrs. A pic with markers of the difference