I just bought a 67 ss/rs with 327. It has a Holly 750, Edelbrock intake manifold, etc to a total of about 350+ HP. I don't know what ratio rear end is in it. The trans is a T350. I drive this car regularly and am not realy into racing as much as a balanced, powerful car. I would like to drop the RPM at 65 to right at 2000 or less to save engine wear and gas. It currently hits about 2600 RPM at 60-65 MPH. Should I change the rear end(what ratio does it sound like now?) or go another route?

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Man, that's gotta hurt!

You didn't say how tall a tire you are running.I input 26" in the RPM calculator.With this tire height a 3.08 ratio will spin your engine 2650 RPM @65mph.If you changed to a 2.56 ratio you still would be spinning 2200 rpm@65 mph.You want a balance of power?Everybody has there own opinion but a 2.56 gear is NOT a balanced gear,unless by "balanced" you mean drive fast on the highway/drive reeeal fast on the highway.I had 2.73's on my 327 Camaro at one time,and it was a total slug under 45mph or so.327's are not very torquey,so that doesn't help.
IMO,you should get a overdrive transmission if you are serious about cruising the highways at 2000rpm.You could run 3.42's out back,so you can have good acceleration,and this would put you right at about 2000rpm's@65 while in overdrive.The best of both worlds (balanced!)IMO.But not cheap.Just my .02

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67 RS RAGTOP # matching,
4X4 CHEVY TRUCK

Hello backfire, I have a 67 RS with 327. Thats about what I was turning with 3:08's, and 27" tires. The motor shouldn't have any problems living at 2500 RPM cruising. But it would be nicer to have better fuel mileage. The way I see it, the best of both worlds costs money. Overdrive transmissions, auto or manual, seem to be pretty spendy. Not to mention the fabrication involved. It all depends on how far you want to take it. Another option is taller gears, but then it wouldn't be as snappy as it is now.

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Steve
67 SS 396,4-sp
67 RS 327,4-sp
72 RS 350/350
69 4X4 suburban 350,4-sp
73 3/4 ton 454/400
http://www.geocities.com/stevocamaro

Backfire,sorry,after re-reading the heading on your post it says"..for highway travel".So maybe acceleration from a dead stop is not that important to you anyway.
One point I forgot to mention though,if your engine is built up like you say,it might not run very well at 2000rpm.If you know what cam is in it you may want to look into how well your set up runs at that low of rpm before makeing any changes.I have read posts out here where people have run into a stumble,or surge at cruise because of too low rpm at cruise.Good Luck!

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67 RS RAGTOP # matching,
4X4 CHEVY TRUCK

[This message has been edited by 67drake (edited 05-28-2000).]

Backfire and everyone else. I have been working on a group deal with Gear Vendor for a purchase. I have recieved permission from them to begin posting the particulars and to start the "sign-up" procedure. Unfortunately, right now I am moving to San Antonio from California to start a Neonatology Fellowship and will be incommunicado for 2 to 3 weeks. Basically, the gear vendor is a bolt on addition to the Powerglide, Th350, 400, 700R4 or any other transmission including Dodge, Chrysler, Ford etc. It is capable of handling over 1200hp and has a 2 year warranty. It can be used as a gear splitter (to get rid of the large gear void in the 1-2 700r4 shift) or as a 23% reduction on any trans. There is a significant price reduction for those who participate with me but I need to place the orders at a single time. Anyone who is interested in the tech details or pricing can email me at supertrick1@yahoo.com - If I dont respond at once I may be on the road... But I will get back to you!
Jim Winter

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web page at web page at http://hometown.aol.com/winterjl/index.html
and more pictures at http://photos.yahoo.com/supertrick1

I WOULD SUGGEST GOING TO A 700R4 TRANNY INSTEAD OF GOING TO A LOWER REAR GEAR BECAUSE U WILL HAVE THE LOW RPMS ON THE HWY BUT U WILL LOOSE YOUR ACCEL. AT LOW SPEEDS

ACTUALLY NOW THAT I THINK ABOUT IT WILL BE HARD TO HIT 2000RPM AT 65....BECAUSE I KNOW FOR A FACT MY Z28 IS AROUND 2200 OR 2300 AT 65 IN OVER DRIVE....AND I HAVE THE STOCK 3.23 GEARS

Thanks for the input. I have heard of the 700r4 as an alternative. However, I have a friend who has worked on cars for many years who says GM built the 700r4 like a pile of @$#%!. He has worked on several where the owner just gave up and went with another like th400 or 350. Do aftermarket rebuilders rework the 700s to improve reliability?

Its my opinion that a 3.31 to 3.55 ratio is the best balance for cruising/performace with a TH350 or TH400. I have a 3.31 in my '69 and I turn just over 3000 RPM @ 70mph.

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Steve McCorry - Central Ohio Camaro Club
'69 Camaro RS/SS-350 - Daytona Yellow
'95 Camaro Z-28 - Sebring Silver
click here to see my car ---> www.mindspring.com/~mccorry (http://www.mindspring.com/~mccorry)

mccorry: What tires are you running on your 69 and what outside diameter do they have? I can't decide what to do with my 69 with a 396 and 4.10 rear. Im not comfy on the highway with such high revs.

The Interstate I usually drive has a posted 75 MPH limit. However, I'm the slow one in the right lane keeping it at 65. With the original rear end of 3.73 and 4 speed on my 69 Z28 the engine speed is about 3400 RPM at 65 MPH. Needless to say I limit my highway travel as much as possible. This vehicle could never be my daily driver.
Mark

I quoted just over 3ooo RPM @ 70 MPH....that is with 225-70R14 tires (26.4 in diameter)...

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Steve McCorry - Central Ohio Camaro Club
'69 Camaro RS/SS-350 - Daytona Yellow
'95 Camaro Z-28 - Sebring Silver
click here to see my car ---> www.mindspring.com/~mccorry (http://www.mindspring.com/~mccorry)

[This message has been edited by mccorry (edited 05-30-2000).]

From my experience with my 67, and its stock 3.31's. At about 3050 rpm and stock D70-14's (200/70-R14's), it ran right at 70 mph. I put a set of Firestone 9/50-14 Town & Country mud and snow tires on it and promptly got a ticket at 82 mph with my speedometer reading 70 mph. If memory searves me, the "snow tires" were right at 29.5" in diameter. I ran them on my stock steel 14" x 6" wheels with 3.75" backspacing. I had to raise the rearend up with coil on shock overload springs to get them to fit and they didn't rub front or back but only top. Why did I do it? I wanted more top end and I was also driving in a lot of mud at that time. I do remember going about 145 mph one night real late when there wasn't anybody on the road like for about 20 miles worth. When I hit town and got in my car pool to go to work, I found out later that I went through a "tripod radar trap" at 145mph and that they were looking for me. Needless to say ,I couldn't go anywhere for about a year without some sort of "cop" in my rear view mirror. Boy, this brings back memories. pdq67