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Old 02-23-2004, 04:20 PM
StealthBird StealthBird is offline
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Default Re: Ram Air IV versus 455 HO

The 1969 RAIV was the pinnacle of the factory produced Pontiac 400 engines. A few years ago, Dan Jensen assembled an absolutely box stock RAIV engine for Musclecar Review, using all NOS parts (including the heads, cam, carb, etc). His goal was not to tweak or modify in any way, but to see what a RAIV truly produced, and lay to rest all the rumors about if the RAIV was really a 400 hp engine. The engine produced over 420 hp. With the 1969 Firebird exhaust manifolds flowing a little better than the 1969 GTO's, and with the lighter Firebird weight, the peak of the Pontiac's 400 engine performance came in the 1969 Firebird RAIV, and yet those still used the 4-pinion HD 10-bolt. The 3.90 gears were standard on RAIV cars.

As stated above, the 1970 455 HO was a d-port engine with a steel intake manifold. Pontiac dropped the ball in 1970 by not having a 455 RAIV ready. Management problems, red tape, and corporate political wars came to a peak in 1970 at Pontiac. DeLorean and Wangers left for Chevrolet in 1969, the RAV program was scrapped, and the PMD engineers were told there was virtually no development money left to create a RAIV 455 due to the enormous expense incurred in their failed RAV 303/400 program. The new management felt there was no simply need for a super high hp 455 when the 400 RAIV was doing just fine. Test engines of 455 based RAIV's were generating over 470 actual hp, but they would never see the light of day. Odd, because it was so incredibly easy to make the 455 version of the RAIV. All the parts were in the parts bin, but Pontiac chose to stick with the RAIV 400.

By 1971, Pontiac was ready to unleash the RAIV 455, but with the compression ratio drop, they chose to drop the RAIV name and stick with the 455HO badge. But the 1971 455HO was nothing like the 1970 455HO. The 1971 455HO was essentially a low compression 455 RAIV, with round port heads and aluminum intake, and of course a much milder cam.
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