I believe L77 is the RPO code for 1970 350/285hp engine. Does any one know the code for the 315hp engine?
The sales codes are listed on the order form but the RPO codes the OP is referring to are what the assembly plants use (I think I have that corret) and are all in the assy manual. IIRC, some of the sales and RPO codes are the same. Regardless, the sales code for the 315HP 350 isn't listed on the order form you posted because it's standard equipment for the 3437 series "GS." The 350HP 455 isn't listed either because it's standard for the 4637 series "GS 455" hence the only engine option on that form is the Stage 1. The sales codes for the 315HP 350 and the 285HP 350 would be listed on all the Skylark order forms since both were optional. Even the 350 2BBL would be an option on certain series Skylarks that came w/the 250 inline 6 plus there was an RPO (& I assume all SCO options also had RPO & sales codes?) for a low compression 350 2BBL for export which I assume was a SCO & IIRC is what was sold to Kaiser for the J-Series Jeeps. On a Sportwagon order form the 285 HP was standard for that series so the 315HP was the only option. I can't remember if the 315 HP 350 was also optional on the LeSabre? I believe all the other big cars came with the 370 HP 455 as standard. There were several series of Skylarks IIRC so I assume multiple Skylark order forms - One for each series or maybe like GS & GS 455 they used one form for 2 of the series. I don't think I have '70 Skylark order forms. Just '72. Someone must have them but the code the OP is looking for is in the assy. man.
Thank You Dano, I looked at my reprint of the 1970 Assembly manual and found the Skylark Order Form. Looks like Y42 is the 315 HP 350.
Y42 thanks! The 315HP was an option in 1970 for the LeSabre. I drove one with 3.23 rear and was surprised how fast it was, comparing it to my then stock seamist green 1970 Wildcat 370HP 455 with 2.78 rear. My Wildcat ran 15.25 1/4 mile. I installed 3.91 posi. and went 14.5 bone stock, I changed cam, converter, B4B intake, Holley 850 went 13.7@99mph with a converter that was too loose. My plan was to run 12's, but I sold the car to a friend and with a new engine and trans it's now running 11's! My new project is a 1970 GS 350 nonmatching numbers but I haven't decided if I will build the 350 or swap to a 455. Thanks again for the info.
Build a 350 (455 swap is so passe). Interesting on the 350 hi-comp. LeSabre. I contend the hot ticket in '70 would've been a Skylark post sedan with the Y42 engine/3sp. manual, H1 trailer tow (which would've required G4 posi & received an automatic no-cost upgrade to an SCO 3.91 rear), and I7 Heavy-Duty cooling to get the clutch fan and get rid of the HP robbing solid fan. I bet the ET of that car would've rivaled a loaded GS 455 auto. w/the std. 2.93 rear if not been even a touch quicker. I bet as an SCO car & dealer that wouldn't take no for an answer from the regional sales office it could've been gotten with a 4-sp., gauges/tach, & BBB alum front drums. My '70 GS 350 4-sp. is very close to that but GS's only got the automatic upgrade to a 3.64 and it wasn't ordered w/HD cooling.
Yes, someone else posted this, and then deleted it. I found this as well in the 1970 Assembly Manual. Y42 was the package including the 315HP L78 engine and N10 Dual Exhaust.
And now another Buick story. Back in 1980ish I bought a 1970 Skylark for spare parts for my 1970 GS455, it had the 350/315HP engine. I sold that car for 100$ to my friend Dan that lived in Mass. He restored the car, changed the cam, added headers, B&M converter and 3.73 posi. and went 13's, after that he did a 455 swap and with Gessler heads and some other goodies went 11.70's, that car was one of the cars used in the Muscle car color history, Buick muscle cars book, pg29, It's gold with white painted top, bucket seat with shorty console. When I can I will try to post a before picture.
This is the before picture of the aforementioned 315HP skylark that was restored by my friend Dan and is the car in Muscle car color history, Buick muscle cars, pg.29. I would say he did an amazing job. Sadly my friend Dan passed away almost 18 yrs ago and the car was sold. I'm sure whoever owns this car now would be surprised to see what it looked like back then.
