i have a 1969 elcamino and i counted the teeth and i got 41 and 16. that means that i have 2.56 in the rear end. is 2.56 gear crap for a 383?? i was hopping it was going to higher than that, 3.73 would of been great. also is there a tag on the diff that would give me some numbers like on a engine to tell me if i am correct or the diff does not come with something like that?
1969_elcamino
If you want gas mileage,they're good gears.
performance wise,my 454 ran low 13's and a best of 12.99 using 2.56's
performance wise,my 454 ran low 13's and a best of 12.99 using 2.56's
Paul-I have a 2.56 in my 69 Malibu. The rest of the drivetrain is a stock bottom end 350 (about 9.5:1), stock heads, aftermarket carb, intake, and headers, and stock TH350 tranny. What Yenko said is about right on takeoff, not too great. I can squeal the right rear tire OK, but after that's over, the pickup is nothing special. However 40-80 mph in 2nd gear is pretty fun. I have definitely gotten spoiled on the highway and love cruising at 2200 rpm. Gas mileage about 13. Saving my cash for a 3.42/posi at this point. I think with a strong 383, a 3.08 gear would make for respectable acceleration. Cheers-Dave.
If just cruising is your goal, keep the 2.56's and put the smallest torque cam you can find in the 383. But unless you have a punched out 454 with plenty of compression and a fat 500+ ft/lbs of torque on tap, that 383 / 2.56 combo sill seem like a slug until you drop in some mid 3 series gears.
G
My First Gen. car's about 9.5 to 1 CR., Strong-Arm 406 with a 292/230, 107/109, .480 hy-cam, (before I learned about cams), with my M-20, 3.31's and 26.5" tall tires got right at 15 mpg om the highway running 65 or so give or take?
AND imho, 3.31's are just about PERFECT!!!!!!
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
AND imho, 3.31's are just about PERFECT!!!!!!
pdq67
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Had it been a 10 bolt rearend it would most likely be an 8.2 inch ring gear. However, they started making the 10 bolt with an 8.5 inch ring gear just a couple years later and its real common for people to swap the 8.5 incher in cause its more durable than the earlier 8.2. However, since youve got a 12 bolt, you have neither of these. On to your gear question, you want acceleration and it sounds like you want to drive it as well. So, have you got any idea on a camshaft? The camshaft really determines what gear and torque converter you would want to run. 3.08 gears are nice cruiser gears, and as you can see, it is possible to push them to go fast as well. But the engine has to be built to work right with the gears.
If you havent got a cam in mind, here is what I would suggest for a mild motor that would be fast as well. Im not sure about your heads, but a good stock cast head with a good cleanup job and some porting or descent aftemarket head would be best. On paper, Harolds voodoo 268 camshaft sounds like it would run great in a 9.5:1 compression 383(you could go a little less, but do your best to keep it over 9:1 for the best results), a performer rpm intake, 2400 converter and anywhere between a 3.23-3.73 gear would work really. If you were gonna drive a whole lot and really didnt plan on running at the drag strip competitatively, Id compromise with a 3.42 rear gear. If your definitely insistent on the best cruise manners and mileage, Id use a minimum of a 3.23 and of course 3.73 gears if you want to push it as far as it can go. Really, much less than a 3.23(like a 3.08 or so) gear may put the engine too low in the power band where it isnt operating very efficiently. Because of that, its possible that it can actually suffer and get less mileage. I wont comment on that cause Im not sure how that camshaft acts and what kinda response it has right off idle, but these things need to be considered and thats why youve gotta match it all up to get it to work right.
Now I havent run that cam of Harolds myself, but the numbers look great for a buildup like this, and while following Harolds threads on this board, its obvious that he has put a lot into these cams so I wouldnt be afraid to say that it will be a runner.
If you havent got a cam in mind, here is what I would suggest for a mild motor that would be fast as well. Im not sure about your heads, but a good stock cast head with a good cleanup job and some porting or descent aftemarket head would be best. On paper, Harolds voodoo 268 camshaft sounds like it would run great in a 9.5:1 compression 383(you could go a little less, but do your best to keep it over 9:1 for the best results), a performer rpm intake, 2400 converter and anywhere between a 3.23-3.73 gear would work really. If you were gonna drive a whole lot and really didnt plan on running at the drag strip competitatively, Id compromise with a 3.42 rear gear. If your definitely insistent on the best cruise manners and mileage, Id use a minimum of a 3.23 and of course 3.73 gears if you want to push it as far as it can go. Really, much less than a 3.23(like a 3.08 or so) gear may put the engine too low in the power band where it isnt operating very efficiently. Because of that, its possible that it can actually suffer and get less mileage. I wont comment on that cause Im not sure how that camshaft acts and what kinda response it has right off idle, but these things need to be considered and thats why youve gotta match it all up to get it to work right.
Now I havent run that cam of Harolds myself, but the numbers look great for a buildup like this, and while following Harolds threads on this board, its obvious that he has put a lot into these cams so I wouldnt be afraid to say that it will be a runner.
i am hopping that i am going to order the bottom end of the motor tommrow, then my friend that has his machine shop, has program on his computer that can tell me what cam would be the best for this build up. i know it will be a roller cam because you can unlock a lot horsepower with it. the block is a 1989 350 so it is ready for the roller lifters, in lifter valley it has three holes that are drilled and tapped so right there i decide to go with the roller cam, roller lifters, and roller rockers.
also how much would a shop charge to change gears??
also how much would a shop charge to change gears??
Labor alone is about 500 dollars usually, unless you know someone that does it and they'll hook you up. But that's what most places have quoted me for labor.1969_elcamino said:
Do you want to swap to a posi also? That'll cost around 270 bucks for a new Eaton posi (don't buy them from Summit or Jegs. Look around on Ebay, send a message to member Big Gear Head or google "Tom's Differentials" for MUCH better prices for the SAME product taht Summit/Jegs sells.)
I think on a 12 bolt you're going to have to get a new differential "carrier" (that's the part inside the rear that is either "open" or "posi/ limited slip") if you want to go numerically higher than 2.73s. So you're either looking at buyin an old open carrier or a new limited slip unit. Because you're buying anyway, I'd rather go ahead and buy the Eaton posi than spend money on a used open carrier.
Gears will run you another 150-200 dollars new.
Installation kit usually runs for about 150 I think.
So if the shop charges you fair price on parts and labor you're looking at:
Labor: 500
Posi: 275
Gears: 200
Kit: 150
So that's roughly 825 bucks. So I'd put aside at least 1000 because once you're into it you'll find out that other parts aren't up to par.
For $1000, I'd opt for a Richmond 5 speed with the deep 3.27 or even deeper 1st gear and keep the 2.56s! J/K , It'd run near $2K with all the accessories .
My point was simply going to be that think of the rear and tranny gears in unison. Modern setups use OD/UD tranny ratios and a decent cruise rpm. If you will use a stock 350/400 with 2.5x 1st gear its much simpler, but still you really want to set the gearing to the design objective of the 383. Low end cruise only 1200-4800, mild street 1800-5200, etc. Then set the gearing to the engine so the system is 'optimized' for its purpose and peak torque output. Keeping an eye on the 'system design' gives the potential of performing beyond expectations.
Tactically, folks around here get $175-$300 for gear swap. Figure $350 for the gears and bearing kit. For that kind of dough, you want the gear ratio ABSOLUTELY CORRECT the first time. No room for a tweak once the motor is built.
First ID the rear end. And I encourage you to think in "systems" terms. Keep the 2.56s for engine break-in, but unless you'll use some sort of U/D tranny, I wouldn't plan on using them. Select final drive ratio once you are very certain as to the purpose and design of the 383.
PDQ, last I checked 3.31s are 12 bolt only and only available NOS GM. 3.23 and 3.42 are the closest nowadays. ( I do love Old Red's 3.31s though! 16 mpg @3000 cruise and looking to run an 11.XX with an U/D tranny! Not bad for Das Boot)
My point was simply going to be that think of the rear and tranny gears in unison. Modern setups use OD/UD tranny ratios and a decent cruise rpm. If you will use a stock 350/400 with 2.5x 1st gear its much simpler, but still you really want to set the gearing to the design objective of the 383. Low end cruise only 1200-4800, mild street 1800-5200, etc. Then set the gearing to the engine so the system is 'optimized' for its purpose and peak torque output. Keeping an eye on the 'system design' gives the potential of performing beyond expectations.
Tactically, folks around here get $175-$300 for gear swap. Figure $350 for the gears and bearing kit. For that kind of dough, you want the gear ratio ABSOLUTELY CORRECT the first time. No room for a tweak once the motor is built.
First ID the rear end. And I encourage you to think in "systems" terms. Keep the 2.56s for engine break-in, but unless you'll use some sort of U/D tranny, I wouldn't plan on using them. Select final drive ratio once you are very certain as to the purpose and design of the 383.
PDQ, last I checked 3.31s are 12 bolt only and only available NOS GM. 3.23 and 3.42 are the closest nowadays. ( I do love Old Red's 3.31s though! 16 mpg @3000 cruise and looking to run an 11.XX with an U/D tranny! Not bad for Das Boot)
No Sir, equivalent of a 4.33 w/M20 being that the 1-4 gear ratios of the Richmond 5 speed run 3.04, 2.18, 1.65, 1.33. 1.33 X 3.31 = 4.40. 5th is 1:1.
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