james the flame 11 Report post Posted January 28, 2008 Good morning everyone, I am narrowing down everything for my 69 build. I have decided to go with my original 351w,edelbrock heads,cam,intake,carb. set up. Also will be using headers. I am going to go ahead and use the original fmx tranny and have it beefed up and maybe a shift kit. Guessing I will have about 400 hp. My car shows to have the original 3.00 rearend. Will that hold up to my drive train? I will hot rod around town but will be travelling about 100 miles one way to car shows also. Please let me know what you think. Also I have the original shifter and console. Can you kind of manually shift this ok?? Or do I need to get rid of the console and put some type of performance shifter in it?? As always, thanks so much for your help. James S. Share this post Link to post Share on other sites
R4K 10 Report post Posted January 28, 2008 Well, I went from a 3.00 to a 3.89 in my coupe, and with a 3-speed auto I actually think I liked the 3.00 better. The acceleration of the 3.89 was huge fun around town and off-the-light, but highway use was out of the question. I'd have gone certifiably Lovecraftian bonkers driving 100 miles in it, lol. Now, with some kind of overdrive, that's a different story. But again, my coupe was powered by a 390, which had a lot of grunt down low and was not a high-revving engine, so the lower gear was more suitable for that drivetrain. Share this post Link to post Share on other sites
1BAD351 21 Report post Posted January 28, 2008 I have whats in my sig and im running 400hp maybe more through my open 2.79, the car still move the hell out, and it still tachs higher then id like on the highway. Unless you plan a OD trans, keep that 3.00. Oh and btw I do track my car and beat the hell out of it and haven't broken the rear yet. However I do not suggest you put anything but street tires on it or you may start breaking things. Basically somethings gotta give and you would like it to be your tires on pavement and not a snapped axle. Share this post Link to post Share on other sites
6T9Mach1 12 Report post Posted January 28, 2008 Well, alot of this depends on your cam. I'm going to assume that it is the Edelbrock RPM cam if you are planning on 400hp. With that cam there are two things that I will recommend. #1) a stall converter #2) a steeper gearing. Durability is not the question with that rear end. A 9" will take a beating and the 3.00 gears would hold up just fine. The reason to run a steeper gearing is to get your engine into its powerband rpm range. A 3.50 gearing would probably suit your set up a little better than a 3.00. If money is an issue, then you could probably get by with the 3.00 but if you want to do it right a 3.50 would be better. RPM's at 60 mph should be about 2700-2800 with a 3.50. Yes you can manual shift the FMX, especially since you have decided to rebuild it and upgrade the internals. A stall converter is another thing you will want to consider. This will also help get you into your powerband rpm. With that cam you should use a stall converter. I would call Edelbrock and see what they recommend. Share this post Link to post Share on other sites
1BAD351 21 Report post Posted January 28, 2008 wait is your rear a 9" I assume 8 because of the 3.00 gears? if its a 9" beat away:biggrin: Share this post Link to post Share on other sites
6T9Mach1 12 Report post Posted January 28, 2008 I believe that all 351's came with a 9" in 1969...if wrong, someone please correct me. Share this post Link to post Share on other sites
6T9rustang 11 Report post Posted January 28, 2008 I agree! 350 gears would be good!:whistling: Share this post Link to post Share on other sites
bnickel 10,004 Report post Posted January 28, 2008 I believe that all 351's came with a 9" in 1969...if wrong, someone please correct me. nope, you are correct. all 351 powered cars got the 9" all the way up until the 9" got dropped from the line. Share this post Link to post Share on other sites
6T9rustang 11 Report post Posted January 29, 2008 nope, you are correct. all 351 powered cars got the 9" all the way up until the 9" got dropped from the line. Thats good! I thought I had a 3.00 8inch in my 351w mach 1. Cool! Share this post Link to post Share on other sites
james the flame 11 Report post Posted January 29, 2008 Thank you gentlemen!! I will contact edelbrock and get their recomendation for a stall converter. I do have a 9 inch rear end. I have not looked at the gears but the tag says it came with the 3.00. Think I will run it for now,see how I like it,watch rpm's and change it later if I need to. Thanks again, James S. in Texas Share this post Link to post Share on other sites
