Russ, ask your engine builder about the torque curve of the cam that he would use. Or tell him what cruise RPM you are looking for & let him select an appropriate cam. I run 3.31 gears with a 26.5 in tire and at 65MPH I am barely at the torque peak of my cam. 3.73 gears would probably put me in a fatter portion of the curve. I feel, never did a real world comparison, that I get better mileage with the lockup feature of the tranny turned off. The 200RPM makes a difference.
On Thu, Mar 18, 2010 at 9:57 PM, Dale <[email protected]> wrote: > I ran a 700R-4 behind my BBC with 3.07 gears and at it ran right at 2000 > RPMs at 70-75 all day long. It made it nice cruising from southern Oklahoma > to KC, Tulsa, Ft. Worth and even Nashville a coupe of times with it. I > forget the exact tire size but if I remember correctly they were something > like 245x55x17 - about 27.5 inches tall. > > Dale > > > ------------------------------ > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Russ Miesner > *Sent:* Thursday, March 18, 2010 9:18 PM > > *To:* [email protected] > *Subject:* Re: [Chevelle-list] I need advice > > I am located about 80 miles from St. Louis, Missouri. Dale, I have > been on your website and have played with the calculator. I think a 3.42 > put me at 2200 RPM's at 70 MPH. I have P255-60-15 tires. Is this too low > of RPM's with the overdrive? I do not intend to do any drag racing just > want it to be a nice cruiser. Our kids live in St. Louis so I would love to > cruise up the interstate to visit them in the Chevelle. (Guess I kinda gave > my age away) I don't think it could get much better than that! > > Thanks for all your help so far and hope to hear more good advice, > > Russ > > ------------------------------ > From: [email protected] > To: [email protected] > Date: Thu, 18 Mar 2010 08:52:36 -0500 > Subject: Re: [Chevelle-list] I need advice > > Depends on where you are as to what shop I'd recommend for a 700R4 - or any > transmission. I've heard good things about Phoenix Transmission in > Weatherford, TX. and had them install one in my old 67 SS396. Their high > horsepower unit (up to 450hp is just under $1800 - > http://www.phoenixtrans.com/html/gmtrans.html. Naturally if you're > nowhere close by Texas, I'm sure there are other shops just as capable. > > There are a lot of aftermarket disc brake companies as well and most are > pretty good. Building a high horsepower engine, you shouldn't skimp on > brakes. Expect a good disc brake setup to run anywhere from $700 to $1500 > depending on company. Don't settle for some $395 eBay special. Baer is on > the higher end but have excellent products. MP Brakes (mpbrakes.com), > Classic Performance (classicperform.com), Inline Tube (inlinetube.com), > and I'm sure there are more offer basic kits from around $700 up or a bit > more if you want power disc. > > Your tire size will have some effect on the rear end gear you might want to > choose. A page at my site, > http://chevellestuff.com/tools/rpm_calculator.htm, will let you play > around with tire sizes and rear end ratios based on your transmission > selection. Transmission gear ratios are shown for the most popular GM > transmissions; just plug in your rear tire size (such as 235x60x15), a rear > axle ratio (like 3.55), a highway speed (like 75mph) and it'll calculate > your RPM. Be aware there will some slippage with an automatic so numbers > won't be exact but they'll be relative regardless of ratio, tire size, etc. > selected. > > Taking my car for example, TH350, 3.36 rear end, 235x60x15 tires and at > 75mph it calculates to 3245 rpm where my tach shows about 3500. Changing to > a 700R4 (and nothing else) with the overdrive ratio the rpms drop calculates > to 2270 at 75mph. I could run as low as a 4.56 gear and still only be > turning 3100 at 75mph with the o/d. > > Dale > Admin - ChevelleStuff.com/forums > > > ------------------------------ > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Russ Miesner > *Sent:* Wednesday, March 17, 2010 10:08 PM > *To:* [email protected] > *Subject:* [Chevelle-list] I need advice > > > > Hello everyone, > > I am a reading person on the list and not so much of a contributer but I > would like your opinions. I have a 65 Chevelle and it currently has a 350 > with a powerglide. Everything is getting tired. I want to overhaul and > stroke the engine by a local engine builder. Plans are to do the rebuild > this summer because he builds alot of racing engines and winter is his busy > time. He said it will have between 425 to 450 horsepower. > I want to put in a 700R4 transmission for better highway cruising. I > have looked at many different transmission companies. Has anyone ever used > Monster transmission? They seem to have decent prices and kits to complete > the conversion. > I would also like to upgrade to front disc brakes. Brakes really confuse > me. I see a really big range of prices. I do not need the high end brakes > just better than drums can offer. > I am also thinking about a March serpentine belt system. Of course, next > comes the rear end rebuild with a posi-unit. Any suggestions on gear ratio? > > Any and all advice would be greatly appreciated, > > Russ > > ------------------------------ > Hotmail is redefining busy with tools for the New Busy. Get more from your > inbox. Sign up > now.<http://www.windowslive.com/campaign/thenewbusy?ocid=PID27925::T:WLMTAGL:ON:WL:en-US:WM_HMP:032010_2> > ------------------------------ > Hotmail: Trusted email with powerful SPAM protection. Sign up > now.<http://clk.atdmt.com/GBL/go/210850553/direct/01/> > -- Rick Schaefer 72 TPI El Camino
