'67 GM 4301 Engine change?

[Jerry W Campbell]

Hi,
   A friend has a '67 GM 4301. I have not seen it. The engine is blown. It has a 4-78 diesel in it.
I was wondering if someone knew if something larger, like a 6-71 or 6V-71 would fit? If he's got to have a new motor anyway it would be nice if it wasn't under powered.
Thanks
Jerry

[Len Silva]

Very confusing post.  As far as I know there never was a GM 4301.  There was a 5301 but the last one was built in '62.  The engines used in '67 were either 6V-71 or 8V-71.  I don't think the 4-71 was used after about 1952.

[gus]

There was a 4103 built in the late '40s or early '50s as I remember, don't hold me to it, but I thought they had  671 engines?

Never heard of a 4301?

[TomC]

GM made a 478 cu in V-6 that was converted from the 477 cu in V-6 gas engine (what is it with GM converting gas engines to Diesels-like the Olds engines?).  It was called a Toro-Flo engine and (being polite here) was a piece of junk.  About 170hp and 440lb/ft of torque.  Don't ever heat it up.  It had a very over square bore of 5.125" and a short stroke of 3.86"-so low end torque wasn't good-but seemed to be alright above 1500rpm (they would rev to over 3000rpm).  These Toro-Flo engines were in a V drive, but the engine faced the right side with the radiator on the right, running through a turbo-hydromatic transmission with a 90 degree drive on the end and an offset drive axle differential.  Not suggested for a bus conversion.

These were typically in a 30ft bus.  The only real conversion would be a pickup size engine in a T drive configuration.  Wouldn't be worth converting to a 6-71.  Good Luck, TomC

[Gary '79 5C]

TomC,
I do not understand your comment of "oversquare" bore of 5.125 ? Is regarding the relationship of the large bore & relatively short stroke ?
Thanks.

[Runcutter]

Sounds like a 3501 or 3502.  GM kept building short (30-foot is right) old-looks, well into the Fishbowl age.  The diesels were, indeed, Toro-flows.  Gas was an option.  All that I remember had hydraulic transmissions.  That's if it's an old-look.

If it is a Fishbowl, it is probably a 3301 or 3302 (amazing, that with each new generation of transit buses we lost seats in the same length of coach).  They, too had a Toro-Flow (II), and were also available with a GM 351 gasoline engine (per Bill Luke's book, City Transit buses of the 20th Century). 

Please try to get a serial number from the builders plate - if your friend has access. 

Arthur

[Jerry W Campbell]

You are right TomC, it is a V-6 478 CI.
The owner told me it has these #'s somewhere.
Series #1049
TDH 3501
I went to see it yesterday. I don't think it is suitable for an engine swap. I think it is only 27 ft long. As far as I'm concerned it would have to be a lot of love and deep pockets. It is a cute little baby bus.
Thanks for the info
Jerry

[TomC]

Gary- over square bore refers to an engine with a larger bore then stroke-like the Toro-flow.  Square is identical bore and stroke.  Under square is where the bore is smaller then the stroke-like what most Diesels are made to get the maximum torque-like the Detroit 71 series with 4.25" bore x 5.00" stroke.  Good luck, TomC