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Bob C (aka q1ap) [ View ] [ Email ] [ Car Ads ] [ Blogs ] St. Augustine, Florida

I'm currently running a crate 350/300 with a 350 trans. and 3:00 gears in a posi ford 9" rear, it's a great cruiser but flat off the line. I have the chance to get a 200r trans. out of a Buick Grand National and wanted to change the gears to 3:42 which I think was the original set up in the Buick. Any opinions on this set up or have a different opinion on what gears to use. Thanks, Bob

Comments

Posted by APLUS  -  06/26/2007 12:38 AM You need to know your rear tire diameter to know around what gear ratio to run. I did the math (tire diameter & od ratio) to run around 2k rpm at 70 mph with my '37 with crate 350 with a Comp Cam and 2004R trans. I ended up with a 3:80 gears with my diameter tires and it'll get up and move out pretty quick and still cruises (70-80 mph) nicely. Very happy with my setup. You don't want to lug the motor at cruising speed with an od trans. The GN trans is a very good (strong) one to run. APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by da34guy  -  06/26/2007 08:00 AM Just got back from a 1700 mile trip in the nu coupe, set up with a 377 cu.in. SBC 200R 3:73 gears in a 9" and 31" tall tires. Perfect setup for me. Go to Bowtie Overdrive website, they have a great calculator to tell ya what gear to run. The 200 has a lower 1st gear , better 2 -3 gears split and a longer 4th (overdrive) Good luck. Kruzin in AZ Don Don [ View ] [ Email ] [ Blogs ] [ Car Ads ] Prescott, Arizona Charter Member since October 2001   Posted by Paradise Road Rod & Custom  -  06/26/2007 10:32 AM If you can give me your tire size I can tell you what your rpm will be at 60 Tim Paradise Road Rod & Custom [ View ] [ Email ] [ Blogs ] [ Car Ads ] Indianapolis, (unknown state)   Posted by q1ap  -  06/26/2007 11:09 AM 235/70 15 at the rear Tim. The crate motor is stock internally and I'm running a tri-power set up. Thanks, Bob q1ap [ View ] [ Email ] [ Blogs ] [ Car Ads ] St. Augustine, Florida   Posted by Paradise Road Rod & Custom  -  06/26/2007 12:07 PM Bob, Recommended RPM at 60 for a small block chevy is 1800-2800. with the change to 3.42 and overdrive trans you would be at 1730 at 60. A little under the recommendation for sbc.But thats not really enough to hurt the performance of the car. With the 350 trans you have now and a gear change you would be at 2537 at 60. You are running a pretty tall tire in the rear so the eats up some gear. 27.95 overall diameter for a 235/70/15 Your currant set up is 2226 at 60 with the 3.00 gear ratio. Hope this Helps Tim Paradise Road Rod & Custom [ View ] [ Email ] [ Blogs ] [ Car Ads ] Indianapolis, (unknown state)   Posted by APLUS  -  06/26/2007 01:12 PM Bob, with your tire size you could run 3:50, 3:70 or 3:89 ratio gears with the 3:70 being the one I would run if it was my car. I'm running an 8" with 3:80 ratio gears giving me around 2139 rpm at 70 mph with the 0.67 4th gear which I'm very happy with. Any of those 3 gear choices should work out for you. APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by APLUS  -  06/26/2007 03:08 PM Just checked out Bowtie's RPM calculator, sure saves a lot of math compared to my method. To find rpm with 2004R transmission (0.67 overdrive ratio) the formula is: RPM = MPH X Gear Ratio X 336 divided by tire diameter x 0.67 Now that I know about Bowtie's calculator I'll do it the easy way from now on. APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by 31tudor  -  06/26/2007 03:18 PM Here out west the highway speed limit is 75MPH. My dad's '32 it had a mild SBC and TH350 with 3.90 gears and 235/75/15's. Lot's of fun around town but not so much fun keeping up with highway traffic! We did a few good road trips with the short gears and it was obvious we had to do something. Enter the 2004R, probably the best thing we've done so far. Like Don said, 1st gear is a little lower and the 2-3 split is much better. Having overdrive means cruising at 80-85 MPH is a pleasure and you're not winding the crap out of the motor! Years ago Shine told all of us that the 2004R and 3.73 (or thereabout) was a perfect street/highway combo and he was absolutely right. No question about it, next time I have the option this is the combo I'm using! If you know where a few 2004R cases are you might want to snag 'em, they're getting hard to find! Hey Don, was I right or what? Would you build another rod WITHOUT a 200??? Eric Hibbs [ View ] [ Email ] [ Blogs ] [ Car Ads ] St. George, Utah Charter Member since January 2002   Posted by da34guy  -  06/26/2007 06:53 PM Yer right Eric. The trip over the weekend was over 1500 miles and averaged 18.8 miles to the gal with that LITTLE 377 And you know how I drive. Don't think I ever went under 85 on the Interstates. Pedal to the metal. KRUZIN IN AZ Don [ View ] [ Email ] [ Blogs ] [ Car Ads ] Prescott, Arizona Charter Member since October 2001   Posted by 31tudor  -  06/26/2007 06:58 PM Bitchin!!! Did Rich's hot 383 powered Willys fair as well? Eric Hibbs [ View ] [ Email ] [ Blogs ] [ Car Ads ] St. George, Utah Charter Member since January 2002   Posted by da34guy  -  06/26/2007 07:13 PM Sure did, but had a hard time catchin me a few times, when I legged out that little engine in OD Ran it up to about 4000 rpm a couple of times and all i saw was a little gray dot in the rearview mirror. Don [ View ] [ Email ] [ Blogs ] [ Car Ads ] Prescott, Arizona Charter Member since October 2001   Posted by dixie  -  06/26/2007 07:40 PM Hey Don can i play? jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by da34guy  -  06/26/2007 07:48 PM Sure ya can Jim Come out here to the wide open spaces and we'll have sum fun!!!!!!!!!!!!!!!!!!!!!!!!! Don [ View ] [ Email ] [ Blogs ] [ Car Ads ] Prescott, Arizona Charter Member since October 2001   Posted by q1ap  -  06/26/2007 11:12 PM OK this is great.............. I've pretty much decided to run a 3:70's gear set up with all the feedback. This what this is all about, it's like haveing a 24/7 cruise night at my finger tips to throw out some questions & answers. Thanks to all, Bob q1ap [ View ] [ Email ] [ Blogs ] [ Car Ads ] St. Augustine, Florida   Posted by RSLUGGOBOY  -  06/30/2007 08:49 AM RPM X TIRE DI. X 3 DIV. BY GEAR RATIO = MPH RSLUGGOBOY [ View ] [ Email ] [ Blogs ] [ Car Ads ] SALINAS, California   Posted by dixie  -  07/01/2007 12:11 AM Well i'm looking for a excuse to come out that way later this year {maybe}=========== have a good weekend ,me an the wife just got in took a 140 mi cruise down south to parrish fl. great nite hit a little rain just cool things off a little.seee yaa. jim grace [ View ] [ Email ] [ Blogs ] [ Car Ads ] dade city, Florida Charter Member since January 2006   Posted by APLUS  -  07/01/2007 02:31 AM RSLUGGOBOY, are you sure about that formula for mph???? I threw so numbers in there and came up with a speed of over 42K........................... APLUS [ View ] [ Email ] [ Blogs ] [ Car Ads ] Austin, Texas   Posted by RSLUGGOBOY  -  07/01/2007 09:24 AM YOU HAVE TO KNOW TIRE DI. SUCH AS 255/70/17 IS 27.09 DI. THEN YOU HAVE TO KNOW WHAT YOU FINAL GEAR IS. SUCH AS 3.73 REAR GEAR W/O.67 OVERDRIVE IS 2.499 FINAL GEAR. CHECK ON LINE DISCOUNT TIRE, THEY HAVE ALL TIRES SIZES AND IT WILL TELL YOU WHAT YOUR TIRE DI. IS. WORKS FOR ME RSLUGGOBOY [ View ] [ Email ] [ Blogs ] [ Car Ads ] SALINAS, California   Posted by ronhotrod  -  07/01/2007 09:06 PM ok guys a 350 Chevy and a 3.8 V6 Buick have different bellhousing bolt patterns unless you get lucky and find a universal case in the Grand National. better check that it will fit first. the 200r is a great trans and you'll like it when installes correctly. ronhotrod [ View ] [ Email ] [ Blogs ] [ Car Ads ] Mount washington, Kentucky Charter Member since July 2001   Posted by Streetrodder007  -  07/02/2007 01:58 PM You can buy a B.O.P. adapter from Summit for about $30 (BUICK OLDS PONTIAC) . I used one on a Pontiac 400 a few yaers ago, very simple and cheap. Streetrodder007 [ View ] [ Email ] [ Blogs ] [ Car Ads ] Port Huron, Michigan Charter Member since April 2006

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