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Second Series · 05-31-2018, 12:53 PM

In reply to your message, I was running the original '47 rear end with a '59 235 and SM420 on the highway, flat between Austin and Waco. It would max out at about 60mph with it floored and no regard to rpm. I tried a 3.55 and with the SM420 the 1st gear is not syncro, so no rolling stops. I had to come to a complete stop before proceeding or lug the engine in 2nd. I thought lugging the engine was worse than reving it up. The 3.55 was free and it had a bent axle so I was out the cost of the rear u-joint. I found a 3.73 and am able to go about 80mph, but again, I floor it. I think a faster rear end would work with a transmission with all syncro and/or an engine with more HP, V8. It's a balance between keeping up with stop and go city driving, and highway driving which can be stop and go as well...

05-31-2018, 12:53 PM	#22
Second Series Registered User Join Date: May 2015 Location: Tukwila Washington Posts: 373	Re: Recommend a place to buy a rearend In reply to your message, I was running the original '47 rear end with a '59 235 and SM420 on the highway, flat between Austin and Waco. It would max out at about 60mph with it floored and no regard to rpm. I tried a 3.55 and with the SM420 the 1st gear is not syncro, so no rolling stops. I had to come to a complete stop before proceeding or lug the engine in 2nd. I thought lugging the engine was worse than reving it up. The 3.55 was free and it had a bent axle so I was out the cost of the rear u-joint. I found a 3.73 and am able to go about 80mph, but again, I floor it. I think a faster rear end would work with a transmission with all syncro and/or an engine with more HP, V8. It's a balance between keeping up with stop and go city driving, and highway driving which can be stop and go as well...