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Willie Makeit · 05-14-2015, 04:00 PM

I have a TH350 behind my 5.3, running 3.08 gears and it does fine. Keep in mind it's no wannabe pro mod car, but I wasn't building a race car when I went the LS route.

I think a 3.42 would be a good choice. A guy I met just last weekend is running 3.42 behind a mild 5.3 and he said he is turning appox 2600 rpm at 55-60 mph. My 3.08's are turning my 5.3 at approx 2100-2200 rpm at 55-60.

05-14-2015, 04:00 PM	#3
Willie Makeit Registered User Join Date: Oct 2013 Location: Alabama Posts: 1,258	Re: 5.3 ls with th350 questions I have a TH350 behind my 5.3, running 3.08 gears and it does fine. Keep in mind it's no wannabe pro mod car, but I wasn't building a race car when I went the LS route. I think a 3.42 would be a good choice. A guy I met just last weekend is running 3.42 behind a mild 5.3 and he said he is turning appox 2600 rpm at 55-60 mph. My 3.08's are turning my 5.3 at approx 2100-2200 rpm at 55-60.