gears from 308s to 355s

racobra · 07-04-2005, 03:10 PM

i had 308s in my 93 cobra put in 355s just wondered how far off will the speedometer reading be. I had the black 20 tooth gear for speed cable. put in the white one which had 23 gears key word there is had I want to put back in the black one just wondered if i will read slow or fast thanks.I read somewhere the white one the way the cut it it only last like 25,000 mile i only have 28,000 on the car the white speedo gear had maybe 15,000 on it and its shot.

Rev · 07-05-2005, 10:42 AM

355/308 x 20 = 23. The 23 tooth speedo gear should be be correct. Can't see why it would wear faster.The 20 tooth would read about 15% too fast on the speedo with the 355's.

Rev

83GTMUSTANG · 07-05-2005, 10:59 AM

Get A 21 Tooth Speedo Gear The Red One Thats The Closest You Will Get Tothe Right Speed Reading ,,,,,,,,i Have A 3.73 An Had A 23t In Mine Read To Slow So I Changed To A 21t With 16 55 245's Mine Reads Bout 5 Mph To Slow But Thats Considered Good.............but Yours Will Read Alittle Faster With The 20t Or 21t

83GTMUSTANG · 07-05-2005, 11:01 AM

What Size Tire Are You Running..........

racobra · 07-05-2005, 04:41 PM

tire size is 245/45r 17

07-04-2005, 03:10 PM	#1
racobra Registered Member Join Date: Apr 2005 Location: ohio Posts: 7	gears from 308s to 355s i had 308s in my 93 cobra put in 355s just wondered how far off will the speedometer reading be. I had the black 20 tooth gear for speed cable. put in the white one which had 23 gears key word there is had I want to put back in the black one just wondered if i will read slow or fast thanks.I read somewhere the white one the way the cut it it only last like 25,000 mile i only have 28,000 on the car the white speedo gear had maybe 15,000 on it and its shot.

07-05-2005, 10:42 AM	#2
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Re: gears from 308s to 355s 355/308 x 20 = 23. The 23 tooth speedo gear should be be correct. Can't see why it would wear faster.The 20 tooth would read about 15% too fast on the speedo with the 355's. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

07-05-2005, 10:59 AM	#3
83GTMUSTANG N-V-ME Join Date: May 2005 Location: SOUTHFIELD,MICHIGAN Posts: 155	Re: gears from 308s to 355s Get A 21 Tooth Speedo Gear The Red One Thats The Closest You Will Get Tothe Right Speed Reading ,,,,,,,,i Have A 3.73 An Had A 23t In Mine Read To Slow So I Changed To A 21t With 16 55 245's Mine Reads Bout 5 Mph To Slow But Thats Considered Good.............but Yours Will Read Alittle Faster With The 20t Or 21t __________________ 88' LX MUSTANG: LINCOLN ROTORS , AIR SUSPENSION FRONT AND REAR, SUBFRAMES, ROLL CAGE, 92' BLOCK, MSD 6AL, ACCEL 8.8 WIRES, ACCEL COIL, EDELBROCK F4B INTAKE (PORTED),2 IN. 4 HOLE SPACERS, HOLLEY 600 CARB.,HOLLEY BLUE FUEL PUMP AN REGULATOR, E 303 (.498 IN. 220 DUR.) CAM, (.535 IN. OF LIFT W/ 1.72 SCORPIN ROLLER ROCKERS), PORTED E7'S, FLOWTECH 1 5/8 LONG TUBE HEADERS, 2 1/2 IN. H PIPE, 2 CHAMBER FLOWMASTERS WITH 3 IN.DUMPS, T-5, 3.73 GEARS, 5 LUG AEROSTAR AXELS, 245-45-17 96' COBRA WHEELS

07-05-2005, 11:01 AM	#4
83GTMUSTANG N-V-ME Join Date: May 2005 Location: SOUTHFIELD,MICHIGAN Posts: 155	Re: gears from 308s to 355s What Size Tire Are You Running.......... __________________ 88' LX MUSTANG: LINCOLN ROTORS , AIR SUSPENSION FRONT AND REAR, SUBFRAMES, ROLL CAGE, 92' BLOCK, MSD 6AL, ACCEL 8.8 WIRES, ACCEL COIL, EDELBROCK F4B INTAKE (PORTED),2 IN. 4 HOLE SPACERS, HOLLEY 600 CARB.,HOLLEY BLUE FUEL PUMP AN REGULATOR, E 303 (.498 IN. 220 DUR.) CAM, (.535 IN. OF LIFT W/ 1.72 SCORPIN ROLLER ROCKERS), PORTED E7'S, FLOWTECH 1 5/8 LONG TUBE HEADERS, 2 1/2 IN. H PIPE, 2 CHAMBER FLOWMASTERS WITH 3 IN.DUMPS, T-5, 3.73 GEARS, 5 LUG AEROSTAR AXELS, 245-45-17 96' COBRA WHEELS

07-05-2005, 04:41 PM	#5
racobra Registered Member Join Date: Apr 2005 Location: ohio Posts: 7	Re: gears from 308s to 355s tire size is 245/45r 17

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