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| | | | Joined: Oct 2004 Posts: 96 Member | | Member Joined: Oct 2004 Posts: 96 | Hey i have a 1961 235 inline 6 4 my truck. Can anbody tell me what its top speed is hooked up to a three on the tree and a 4 speed. And also how can i increase the performance on a budget scince i dont have alot of money. Any advice would be appreciated. | | | | | Joined: Mar 2004 Posts: 734 Shop Shark | | Shop Shark Joined: Mar 2004 Posts: 734 | What's your idea of better performance? Asking about top speeds in regards to transmissions makes me think you're after cruiseability. Also, do you mean a 3spd vice a 4spd? Presuming this is what you mean, the 3 spd's and 4 spd's both have a 1:1 final drive ratio. The SM420 4 spd may as well be a 3 spd as you'll probably never use the 7.06 granny 1st gear. Check your tire size and your rear end gearing, then use this rpm calculator. rpm calc. For sh!ts and grins, type in an overdrive ratio of .72 or .63. Then your next question will undoubtedly be, what OD tranny should I use! -David Kustoms-and-Sleds | | | | | Joined: Jan 2001 Posts: 687 Shop Shark | | Shop Shark Joined: Jan 2001 Posts: 687 | mugsy is right,
Increasing top end cruising speed (a common upgrade) is a matter of changing rear end gears and/or switching out trannies for one with overdrive.
Many people here who want to drive their older vehicles daily (especially half ton, light duty trucks and sedans) want better cruising speed so this topic has been discussed in detail several times before. Do a forum "search" using key words like "overdrive", "top end", and so on. You should be able to pull up something that can help your case. If not just let me know.
-ftyler | | | | | Joined: Jun 2000 Posts: 2,773 'Bolter | | 'Bolter Joined: Jun 2000 Posts: 2,773 | 61 1/2 ton should have either 4.10 or 3.90 gears, iirc. Another factor is tire size, specifically the rolling radius, measured from pavement to the center of the wheel. You double that distance to get the tire diameter for the formulas. Cruising rpm for the stock 235 is 2,200 to 2,700 rpm. Above that for extended times and your rods start to stretch and fatigue. Here's one link to a calculator, there are a lot more out there. http://www.ring-pinion.com/calculators/calculatorsind.html
Fred
52 3600
69 C-10
| | | | | Joined: Jun 2003 Posts: 41 Junior Member | | Junior Member Joined: Jun 2003 Posts: 41 | Fred T,
I guess I'm twisting my ol' 235 too tight then. I cruise at 3,000 rpm and just got back from Cruisin' the Coast which was a 750 mile round trip this year. Last year it was 950 miles. Both times it was 500+ miles on the interstate at 3,000 rpm which is 70 mph with my 3:55 gears and 27" tall tires. That's where this 235 wants to run and that's where I let it run. No problems in 14,000 miles, or not yet anyway. Maybe I just don't know how to do it, ha. | | |
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