MovieChat Forums > The Seven-Ups (1973) Discussion > What Motor did that '73 Bonneville have?

What Motor did that '73 Bonneville have?


I know the Ventura was a 350 4v.Excellent chase.

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I believe it had a 400 engine.

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Doesn't really matter. Both cars were customized to the hilt. '73s were the first year that the compression ratios were drastically reduced. If they had used stock vehicles, the chase would have taken twice as long--no compression, no acceleration, no power at all.

"You eat guts."--Nick Devlin

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I think Grand Villes came with a 455.

People rag on those cars for the detuning and whatnot but they can still be made to move with few changes. Monster if you tweak them even more and beef up the suspension.

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Choked off with emissions crap, low compression, and low rearend ratios. Probably more than a "few changes."

They were good-looking cars in the early and mid-70s, but it was a decade before Detroit figured out how to put a little power back in them.

Oh, well!

"You eat guts."--Nick Devlin

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Not really, it's just tacked on ancillary crap to the car after the fact so it can be taken off. The compression ratios would take more to change though.
The 71s were almost identical and they didn't suffer like the later years.

I have a 74 Impala which is essentially the same platform with only a 350 in it, the car flies for something 4,000lbs. However it has no emission equipment on it (I think it was removed in the 70s), factory duals and an aftermarket intake/4 bbl Holley as well as some other things.

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This is a really old thread, but the '73 Bonneville would have had a 400 more than likely but could have had a 455.

The Grandville used in the chase though would definitely have had a 455. It was still good for 250 hp and 370 ft/ibs torque. Not shabby for the era.



Conquer your fear, and I promise you, you will conquer death.

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Horsepower dropped alot after GM in 1971 decided all cars had to run on 91-octane lead-free gasoline.

From 1969 - 1974, alot of models suffered a 50% drop in HP. Also, the SAE measurement of HP changed from gross to net.

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True, and then they were smogged down in '73 and then really bad in '75 with the catalytic converters.

Conquer your fear, and I promise you, you will conquer death.

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Either a 400 or 455. A 75 model would have had a 455.

Standard equipment on Grand Ville models included a 455 cubic-inch V8 engine (for 1971-74 models, a 400 cubic-inch V8 was standard and the 455 optional for 1975)

The 73 in the movie could have had either.

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i'm going with the 455 also.

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After thinking about it a bit, a 455 equipped Pontiac from that era would have had 455 emblems on the grille, the lower front fenders, or both. So I'm sticking with 400. 455 was optional, but it would have let you know with the appropriate emblems...

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sounds about right.

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