bigdooly

Hello Oldsmonuts.
I recently picked up a 71 98 parts car. I bought it for the allegedly rebuilt 455/th400. It was an aborted resto by original owner. I have not ran it, but motor is free. {not locked up}.
My intention is to install it in my 75 88 conv, as the original 350 I had built for it is now in a 79 TA .How does the 71 motor rate? I am under the impression it should still be over 300 hp in 71.
I am not well informed on 455's. I am not looking to build a 1/4 mile motor. just a healthy cruiser. If she runs well, I may just leave it alone, or maybe throw some bolt on goodies at it.
It is painted a hideous blue. Oh, I failed to mention it has been sitting for 15 years. What are the differences in the performance 455's vs the boat motors? Thanks in advance.
Jim

joe_padavano

The only engine available in the 1971 Ninety Eight was the RPO L31 455 4bbl motor. 1971 was the first year for SAE net HP ratings, and Olds provide both the net and older SAE gross ratings for comparison that year. The L31 was rated at 320 HP/ 460 ft-lbs under the older gross standards and 225 HP/360 ft-lbs with single exhaust or 250 HP/370 ft-lbs with dual exhaust under the SAE net testing.

bigdooly

Thank you Joe.
This will do very nicely with a few minor upgrades.
Jim