hey, i'm driving an 85 riviera. it has about 107,000 miles on the factory 307. i want to replace the engine with a bigger SB because i think my car is slightly underpowered. I was thinking about an olds 350 but i was also wondering how big i could go without having to do something ridiculous during the instalation. I was also wondering about the horsepower/torque numbers for a stock 350 and any other engine that would fit in the car and mate with the transmission. any help is much appreciated.
Oldsmobile had a smallblock 403 from 1977-1979(?). Same dimensions as the 307/350. They were in Olds Ninety Eights, Buick park Avenues and some Rivs.
403 to replace 307 For our 86 Regal Limited daily driver the original 307 went from no oil added between 3000 mile oil changes to using 5 quarts of oil for each tank of fuel. Saw this as an great opportunity to dump the 307. Went with the 4B block from a 1978 Caddy and 7A (quarter inch high "A" rather than the full size "A" which are 307 heads from mid 80 307s) heads from a 1972 350 to give it about 9.5 to 1 compression with 0.030 oversized 403 pistons. Cut the valve openings in the 7A heads for the larger intake valves from the 403 heads, but did not touch the exhaust valvues since "A" part of the 7A heads means hardened seats. If installing 350 heads on a 403 you will need to drill out the head bolts and open up the water passages in the heads to match the passages in the 403 heads. With an Edelbrock performer intake which provides for all the extra sensor locations, this engine can be run on your computer. This should give you enough torque to properly propel your Riv in style.
thanks to both of you. very helpful info. the only other thing i'd like to know is the horsepower/ft. lb. torque numbers on the olds 350 and the olds 403. i don't want to do too much performance wise. i am curious though as to what kind of horsepower these engine put out.
okay i just found a site that said an olds 350 put 160 hp to the rear wheels but that doesn't seem right. i knew a guy who put a 350 in his old chevy truck istead of the inline 6 and that truck was fast. maybe i'm not looking at it right but i'd apreciate some good info. thanks.
