65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => 1964-1967 300CI Engine => Topic started by: kcombs on September 07, 2021, 04:47:46 PM
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Anybody running a stock 300 with a four speed or a T5? How's the performance? I am now retired and getting out to the shop more, planning on building my Bucamino. My original plan was to use a GS frame and a four, or five speed. Now I am thinking, I hardly ever pass anymore and I am through drag racing at 73 years of age, just want power when I floor it and a nice sound. I have a convertible with a four barrel 300, but with a 300 automatic behind it. Not sure how much power a 300 has with a stick shift. Any helpful comments appreciated.
Kurt
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Hi,
I drive a 65 Skylark convertible. It has the 300 motor with 4 barrel and wide ratio 4 speed.
I have a 3.36 posi rear and dual exhaust with a balance tube. I think this combo is plenty quick and fun to drive. I converted my car from 2 barrel carb, with automatic transmission and open 2.78 rear gear. I acquired the correct 4 speed parts from a forum member here @ 65GS.
The conversion from auto to 4 speed would not be complete unless you upgrade the rear end gear set. My Skylark performance really improved drastically with the 4 speed and new rear end gear upgrade.
My 4 speed is a T-10
Regards,
Robert
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Hi Robert,
The car I am making into a Bucamino is a column shift shorty wagon. So it probably has some good peg-leg gears. The 300 smokes, so I will have to have it rebuilt or find a low mileage engine removed to install a later model Chevy engine. Your four speed is a T10?
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Hey Kurt,
I have a Richmond 5 speed behind the 300 in my '66 Special, it's real fun to drive..... immensely better than the 2 speed auto!
The 5 speed is the close ratio without overdrive, 3.26 first gear and 1:1 fifth.
With the 2.78 rear, it's a (2.78 * 3.26) = 9.06 ratio from a stop in first gear. Takes a bit of clutch slipping to get going but it's fine. Combo is good for 70-75 mph at a comfortable 2500 rpm.
Ideally, I'd like a little more gear off the line, and a 5th with an OD ratio for lower rpm's at 75-80 mph. But the Richmond was such a great deal at $1300 slightly used. It was also called the Doug Nash 4+1 in it's earlier days.
I added the 64 alum 4 bbl intake and dual exhaust to the 300. Runs nice!
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I have a 65 Skylark with 300 4 bbl, T-10 4 speed, and 3.23 posi. I recently installed 64 alum heads and intake, as well as an old set of Poston headers that I had ceramic-coated. It is a real blast to drive, but sometimes it's hard to keep up with traffic on the highway, so I am going to install a new Tremec TKX 5 speed.