Hello there,
I have '63 Riviera, which has had originally 401 nailhead. Afterwards someone has swapped the '73 455cid engine in to it (probably because of DynaFlow problems) accomppanied with th400.
Could you enlighten me about the hp and torque of these both engines? How is the '73 SAE net hp comparable with those given for '63 nailhead hp's?
What are the differences between '73 455 and '71 455? C/R is different, could I tune up the '73 by changing pistons and connecting rods from '71?
Thanks in advance
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8, the harmony of nature
The 401 Nailhead was rated at 325 HP and 445 torque. The 425 Nailhead was rated at 340 HP and 465 torque. The 70 455 was rated at 360 and 370 hp and 510 torque (same rating system as in 63). Pistons and chamber volume were the difference between the 70 and 73 455. Pistons with less dish volume and some surfacing of the heads will yeild a 455 with similar compression to the 70 455. Nailheads will make power lower in the rpm range then the 455, and are far more rpm limited then the 455 due to small valve heads. All that being said, I think the Nailheads are more unique and way cooler then 455s.
Steve B.
67 GS 525 Buick Stage IV
66 GS Convertible
65 GS HT
63 Riv
02 Subaru WRX Turbo
03 Ford Cobra Convertible (Factory Supercharged)
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