Engine Swap 1970 Skylark Convertible 350 2bbl.

Ronny B

New member
I'm working on a 1970 350 2 bl, it sat for over 20 years, oil was black like tar and rocker covers were in the trunk. I rebuilt the Rochester 2 bbl, new points, rotor, cap, wires, plugs, coil, fuel pump, changed the oil, using fresh gas in a day tank. Also pulled the rocker shaft, rockers and push rods, some rods were rusted but all are straight and cleaned. One set of lifters #8 had no spring or give to it under hand pressure. Real low compression in 3 cylinders 30-50 and zero in #2 cylinder. I'll recheck this after running some more.

Started right up but very noisy top end and an intermittent knock, every so often. It revs pretty good- I didn't rev it too high. Thinking about putting diesel fuel or transmission fluid in oil to see if it helps to loosen every thing up.

I can buy a 350 2 bl out of a 1976 Century with 85 K on it, says it runs good, no smoke, no knock, on a stand, can't start it.

Will it drop right in to the 1970 Skylark? Does it only have 135 HP?

assuming it's a Buick 350, yes it should drop in. you can tell it's a Buick if the distributor is in the front of the engine.

GM engine swapping isn't supposed to have started until the 1977 model year but if it's a late build 76, your car might have gotten one of the 77 motors. and in 77, a Buick could have any of the 4 different make 350s in it.

and does the 76 only have 135 HP?

yes, but that doesn't mean what you think it means. 1976 was rated according to more modern SAE Net Horsepower specs.

1970 was rated according to the Gross Horsepower standard ( which everybody was using at the time ).

so, while the 76 will be down on power relative to the 1970, it's not going to be anywhere near as bad as you might think from just looking at the advertised HP numbers. you need to lop about 1/3 off of the 1970 numbers in order to compare them to a 76 engine.

the hands down most powerful Buick 350 is the 1970 'SP' code 4 barrel but your 76 engine does have some advantages.

you've got the capscrew rods and the large diameter oil pickup and the HEI distributor already. so if you decide to build for power, you've got a leg up over an earlier engine.