1969 Beaumont with LM1 engine option

Vipersxt · Member

1969 Beaumont with LM1 engine option

73SC · A Poncho Legend!

There are 134 cars in the 1969 original registry with serial numbers sampling a total of 16,737 cars.

62% are 307 and a few listed as L65 350 for a statistical total of 10,367.

9.7% are listed as L48 350 for a statistical total of 1,624.

1.6% are listed as LM1 350 for a statistical total of 268.

In the absence of any other better data or educated guesses I'd say at least 268 LM1 cars were produced in 1969.

I have often wondered why the LM1 350 4 bbl was even offered. It was rated at 255 HP when the L65 350 2bbl was rated at 250 HP. The L48 4bbl was rated at 300 HP. All were single exhaust cars in 1969.

-- Edited by 73SC on Wednesday 15th of April 2020 08:27:16 PM

69 beamont custom coup · Veteran Member

My L48 350 m20 4 speed car came from factory with dual exhaust. any production numbers on those?

69 beamont custom coup · Veteran Member

Ray,

So the 1624 number of L48 cars, How many were m20 4 speeds with factory dual exhaust? Is that info available? Appreciate any help. thanks Randy

65Camino · Uber Guru

Would it say on GM Canada paperwork ?

73SC · A Poncho Legend!

69 beamont custom coup wrote:
Ray,
So the 1624 number of L48 cars, How many were m20 4 speeds with factory dual exhaust? Is that info available? Appreciate any help. thanks Randy

Using my same statistcal approach using cars in the orginal registry, only 101 cars have transmission and engine identified and 6 are L48 M20 combination. There are a total of 13 L48 cars in the registry and 4 speeds make up a significant proportion on the cars. I think this makes sense since the L48 at 300 HP was a performamce engine and we have many cases of anecdotal evidence suggestong this combo gave away little if anything to the SD396 cars. So the statistical data and analysis we have at hand suggests 750 more or less L48 4 speeds in 1969.

NOTE: I reviewed my work today August 15th and found that one L48 car is listed as HD Manual which I believe is a 3 speed manual trans and this does statistical change the result to:

Manual L48 cars - 750 more or less

4 Speed Manual L48 cars - 625 more or less.

-- Edited by 73SC on Sunday 15th of August 2021 12:16:42 PM

68beaumont · Guru

73SC wrote:
There are 134 cars in the 1969 original registry with serial numbers sampling a total of 16,737 cars.
62% are 307 and a few listed as L65 350 for a statistical total of 10,367.
9.7% are listed as L48 350 for a statistical total of 1,624.
1.6% are listed as LM1 350 for a statistical total of 268.
In the absence of any other better data or educated guesses I'd say at least 268 LM1 cars were produced in 1969.
I have often wondered why the LM1 350 4 bbl was even offered. It was rated at 255 HP when the L65 350 2bbl was rated at 250 HP. The L48 4bbl was rated at 300 HP. All were single exhaust cars in 1969.

-- Edited by 73SC on Wednesday 15th of April 2020 08:27:16 PM

My understanding of the 1969 LM1 350 was that it was actually close to 275 HP instead of the "official" 255 hp. Some sources think it may have been something to do with NHRA classes.

Howmac · Guru

My 69 Chevelle wagon ( Balitimore built , and sold new in Canada) also the LM1 with a factory# M20 .

-- Edited by Howmac on Sunday 15th of August 2021 03:49:55 PM

HK1837 · Addicted!

The 1960's LM1 was only available in the USA for the 1968 months of 1969 model year (so basically September to December 1968), it was replaced by the L65. Not sure about Canadian cars though. We got the LM1 in Australia from April 1969 through to the end of 1970 but only with a Powerglide, the manual HT and HG GTS350 Monaros were L48 engines.

The 250hp L65 versus the 255hp LM1 is an obvious under-rating by about 15hp. They are the identical engine other than the intake and carb. When you apply the same intake and carb as the L65 to a 327 it was rated as 235hp (standard V8 on 1969 full size), but with the basically identical 4BBL intake and carby off the LM1 on the 327 it was 250hp (1968 L78), both are 9:1 engines with the same specification heads (small port, 69cc chambers, 1.72/1.5 valves).
In Australia the L48 was rated the same as in the USA and Canada, ie 300hp@4800 and 380lbft@3200, the LM1 was rated at 275hp@4800 and 365lbft@3200rpm, which is the same torque as USA but 20hp more. These were both rated for 97 Octane fuel and with slightly different distributor curves to their USA versions but that distributor variation was to account for the different fuel (the LM1 was rated for regular fuel in the USA and the L48 for high octane fuel), and also so they could run a common distributor between the two in Australia (which was the 1968 L78 distributor, 1111150). Given the higher Octane fuel and more advance used on the Australian LM1 I'd guess the standard USA spec LM1 to be close to 270hp. The L48 and LM1 over here are identical to those in North America other than the sump/pickup, LH Ramshorn exhaust manifold (both right and left kick backwards) and the distributor as mentioned, they were both Tonawanda engines other than the final few L48's which came from McKinnon.

69 beamont custom coup · Veteran Member

Exactly what I was after Ray, Appreciate it.