Rear Posi (is it worth the money) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**MikeB** · 03-02-2024, 01:33 PM

1969Stepside -- Nice 327 build!

Maybe I missed it, but I didn't see which transmission your truck has, or how tall the rear tires are. Those are factors in determining which axle ratio to use for spirited performance. Your 3.08 may work fine if the trans is a TH350 with a slightly higher stall converter and/or 26-27" tall rear tires. But with 29" tall tires, things may be a bit sluggish, especially with a 327 and a 219/227 cam.

My 69 once had a mild 383 with a 3.08 axle, and a TH350 with Hughes 2000 converter. That thing would smoke the tires in low gear and do a serious chirp on the 1-2 shift. However it probably made at least 50 lb/ft more torque than your 327.

Looks like a good site to calculate and compare tire dimensions.
https://www.calculator.net/tire-size-calculator.html

03-02-2024, 01:33 PM	#38
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 4,038	Re: Rear Posi (is it worth the money) 1969Stepside -- Nice 327 build! Maybe I missed it, but I didn't see which transmission your truck has, or how tall the rear tires are. Those are factors in determining which axle ratio to use for spirited performance. Your 3.08 may work fine if the trans is a TH350 with a slightly higher stall converter and/or 26-27" tall rear tires. But with 29" tall tires, things may be a bit sluggish, especially with a 327 and a 219/227 cam. My 69 once had a mild 383 with a 3.08 axle, and a TH350 with Hughes 2000 converter. That thing would smoke the tires in low gear and do a serious chirp on the 1-2 shift. However it probably made at least 50 lb/ft more torque than your 327. Looks like a good site to calculate and compare tire dimensions. https://www.calculator.net/tire-size-calculator.html __________________ Mike 1969 Custom/10 LWB -- owned for 37 years. 350/TH350, 3.08 posi, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. Hedman stainless headers. Old Air installation in progress. 1982 Custom Deluxe 10 SWB -- converted from 250-six to roller cam 350 w/ Vortec heads -- sold 1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it! 1969 C10 (not the current one) which I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 26 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.