2000 Pontiac Firebird MMS 421 Concept
Above Images ©IMAGE CREDITS - General Motors Corporation
Morgan Motorsports put together this 2001 Trans Am MMS 421
The parameters set down were that the power would have to 1) come from natural aspiration - no turbocharger, supercharger or nitrous oxide in use here, and 2) be in the output range of 600 horsepower. No small feat, indeed.
Starting with a sleeved block resulting in a 4.125 bore the MMS team installed a SCAT billet crankshaft. ROSS 2618 alloy pistons sit atop Callies forged I-beam 6.125 rods.
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In Detail
| submitted by | Richard Owen |
| displacement | 6899 cc / 421.0 in³ |
| bore | 104.77 mm / 4.12 in |
| compression | 11.7:1 |
| power | 466.1 kw / 625.0 bhp |
| specific output | 90.59 bhp per litre |
| bhp/weight | bhp per tonne |
| torque | 745.7 nm / 550.0 ft lbs |
| front tires | 295/35-ZR18 |
| rear tires | 295/35-ZR18 |
| f brake size | x 356 mm / x 14.0 in |
| r brake size | x 356 mm / x 14.0 in |
| front wheels | F 45.7 x 25.4 cm / 18.0 x 10.0 in |
| rear wheels | R 45.7 x 25.4 cm / 18.0 x 10.0 in |
| gear ratios | :1 |
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