The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Attaching a 350 to original 4 speed manual trans

**'68OrangeSunshine** · 03-11-2014, 04:19 PM

I may be off-base, since I'm a '67-'72 monomaniac, but you should have the SM420 treansmission if it's the original 4-speed in a '65. The OEM bellhousing is GM p/n: [GM11]3815891 with a 4-9/16'' diameter opening.
It should bolt right up to any SBC, BBC or L6 made from the mid '60s to late '80s.
The SM465, introduced in '68, takes a bellhousing with a 5-1/8'' I.D. but engine-mating bolt patterns are the same.

03-11-2014, 04:19 PM	#2
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,143	Re: Attaching a 350 to original 4 speed manual trans I may be off-base, since I'm a '67-'72 monomaniac, but you should have the SM420 treansmission if it's the original 4-speed in a '65. The OEM bellhousing is GM p/n: [GM11]3815891 with a 4-9/16'' diameter opening. It should bolt right up to any SBC, BBC or L6 made from the mid '60s to late '80s. The SM465, introduced in '68, takes a bellhousing with a 5-1/8'' I.D. but engine-mating bolt patterns are the same. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.