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#1 |
Registered User
Join Date: Sep 2006
Location: California
Posts: 11
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Do the 3:08's have to go???
Hey gentlemen,some of your thoughts please. Got a 69 w/ 350 all stock sept' for Performer intake,600 cfm Edelbrock,HEI,cast iron exht. with 2.5 pipe and 400 T/H trans.Rear end is 12 bolt full of 3:08's. This thing won't get out of it's own way from dead stop hardly. Forget bout pulling my bass boat or jet boat to the lake.I am thinking I'll have to put the 3:73 rear end backin, hate to do that. Those 3:08's are quite and soo smooth and sure get better mileage. Any thoughts truely appreciated....Thanks
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#2 |
I have a radical idea!
Join Date: Jan 2005
Location: Sweet Home Alabama!
Posts: 6,513
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Re: Do the 3:08's have to go???
I think you have another problem. My red 69 C-10 has 3.08's with a stock 350 with a Q-jet and a TH-350 and it will spin the tires easily from a dead stop, and pulls my car trailor and race car decently. It is not an all-out power house going up a long grade with a car on the trailor, but it does OK. Its sounds like you might have a timing or carb problem if its that much of a dog, unless the engine is very tired.
BTW, ![]()
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club! |
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#3 |
State of Confusion!
![]() ![]() Join Date: Jul 2002
Location: Gulfport, MS USA
Posts: 46,901
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Re: Do the 3:08's have to go???
my 69 POS parts truck with a smog motor 305/T350C/3.08s would smoke them without hesitation. Sounds like there are other issues, maybe tranny issues.
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Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! |
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#4 |
Senior Member
Join Date: Aug 2002
Location: Valley Center KS
Posts: 3,525
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Re: Do the 3:08's have to go???
Sounds like a tuning problem to me.
If it's not, then a good (but possibly pricey) option is 3.73s with a OD tranny. I'm now getting 18.5 mpg out of mine (but it's also fuel injected) |
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#5 |
I am a Referee of life.
Join Date: Jun 2000
Location: Greensboro N.C.
Posts: 13,993
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Re: Do the 3:08's have to go???
Red, I think they are right.Either that or you're expecting too much.In the long run you may want to consider a 700R4 for it though.You will need a 3:73 for that.3:08's were the standard gear for auto's so it should run and tow a boat with no problem.
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The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" |
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#6 |
Project underway - finally.
Join Date: Feb 2007
Location: Greenville, SC
Posts: 493
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Re: Do the 3:08's have to go???
One more vote for "it's not the gears". My 84 with a 350 and 3.08's and a th-350 got up fairly quickly. Bring it to the dragstrip and do some tuning... mine ran something like 17.10s stock. Timing and carb are the areas to look for... make sure that the butterflies are opening fully, that's surprisingly easy to miss. Also make sure your secondaries are opening.
-Brian
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1972 GMC Pre-resto... awaiting allocated funding. |
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#7 |
Next project: 1970 K10
Join Date: Feb 2004
Location: Fort Collins, Colo 80524
Posts: 6,685
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Re: Do the 3:08's have to go???
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Bob 1970 Chevy K10 LWB "Goldie" 350/TH350 next project!! 1981 Chevy C10 LWB 355/TH350 - My son's truck LS SWAP FORUM! Tons of LS swap info here! PLEASE CLICK HERE TO SUPPORT THE GREATEST BOARD ON THE NET! CLICK HERE FOR THE FAQ INDEX by KRUE |
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#8 | |
Licensed to Thrill!
Join Date: Apr 2006
Location: Northwest, GA
Posts: 1,673
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Re: Do the 3:08's have to go???
x2.
Quote:
(Standard truck gear is actually 3:07 isn't it?) DLB |
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#9 |
Senior Member
Join Date: Jan 2000
Location: Cincinnati, Ohio
Posts: 1,492
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Re: Do the 3:08's have to go???
Just put a 5.14 in my 55 Chevy and that did the trick......lol I could pull stumps if necessary..............
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#10 |
Junior Member
Join Date: Jul 2006
Location: Delran, NJ
Posts: 458
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Re: Do the 3:08's have to go???
What is your RPM in OD at highway speed? I looked into this a while ago when I was considering a swap. I even whipped up a spreadsheet that shows RPM at a given speed in a given gear with different combinations of transmission and rear ends. It was fun. I'm a geek.
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#11 | |
Licensed to Thrill!
Join Date: Apr 2006
Location: Northwest, GA
Posts: 1,673
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Re: Do the 3:08's have to go???
Quote:
Ask me in a year. ![]() (New baby in the house = no funds). DLB |
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#12 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: Do the 3:08's have to go???
Get rid of the power robbing TH400.You don`t need it with what you have,anyway.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#13 | |
FarmBoy.
Join Date: Feb 2005
Location: Rhinelander, WI
Posts: 1,103
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Re: Do the 3:08's have to go???
i have 3.07's behind my 307 and 3 speed, and i can catch rubber in both 1st and 2nd gear, and probably 3rd if i reallllly tried. but, still.
i agree. gears should be good. you won't be launching like with 4.56 out back, but, still should have some get up. -Sam.
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1969 GMC C1500. long fleet. 307. 3 on the tree. 3.07 gears. Oliver green. Bent and bruised. Daily Driver. Quote:
http://67-72chevytrucks.com/vboard/s...d.php?t=242993 |
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#14 |
'69 Step
Join Date: Mar 2005
Location: Marion, Texas
Posts: 722
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Re: Do the 3:08's have to go???
I like my 3:08s
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It's my truck, and Yes, I CUT the dash, so what?? |
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#15 |
More Cowbell....
Join Date: Mar 2004
Location: Puckett, MS
Posts: 3,569
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Re: Do the 3:08's have to go???
3.08s here as well....Had 3.73s in there, but needed more interstate speeds. Swapped with GMan. I can do a descent scratch from a dead stop. Agree you may have other issues.
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There once was a member from Puckett.....Who ( fill in the blank blank blank ) bucket |
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#16 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: Do the 3:08's have to go???
Red 69 C-10, one more for the "it's not your rear end" vote.
FYI: I have a 69 with a tired 350ci with quadrajet and 350 trans with 3.07 rear end. Some years ago I pulled an 18' trailer loaded with a full size tractor, bush hog and other equipment for about 100 miles and had absolutely no problem towing. I also have towed other vehicles, trailer full of lumber, etc. with it and haven't had any problems. As others mentioned, it could be carb, tuning, transmission, or engine. At my age I'm not into peeling out for the fun of it, but I've stepped on it on occasion to "blow it out" ![]() |
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#17 |
Project underway - finally.
Join Date: Feb 2007
Location: Greenville, SC
Posts: 493
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Re: Do the 3:08's have to go???
I think we've overwhelmed the poor guy.
First off, I forgot to welcome you to the site. Secondly, want any help getting to the problem? -Brian
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1972 GMC Pre-resto... awaiting allocated funding. |
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#18 |
Active Member
![]() Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
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Re: Do the 3:08's have to go???
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#19 |
Registered User
Join Date: Dec 2006
Location: Rhode Island
Posts: 602
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Re: Do the 3:08's have to go???
Maybe a trip to the local chassis dyno is in order. For about $150 (here in RI) they'll tune carb and timing to provide optimal performance for your normal requirements.
Without knowing the details, were it me, I'd attack the issue in this order Tuneup (plugs, wires, ignition module, coil, free breathing intake etc) Carb a/f ratio (you want 14.7:1 when cruising and 12.5:1 when mashing on the gas), Timing (run as much advance as you can w/o pinging or hard starting), Exhaust (minimal back pressure, especially the mufflers), Cam design (profile) and adv/retard, Cam health (are the lobes worn off? Are the timing chain/geears worn?) Heads (both flow and compression ratio), Torque converter stall Swap the tranny for a TH350 or TH200 Change the R&P ratio to a 3.42 or 3.73
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69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe Last edited by mnunn454; 09-12-2007 at 06:38 PM. |
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#20 |
Registered User
Join Date: Dec 2003
Location: here
Posts: 5,789
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Re: Do the 3:08's have to go???
This winter Im swapping my 3:07's for 3:73's. Its my toy & the gears will make it more fun.
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#21 |
Overdrive club
Join Date: Sep 2007
Location: apache junction, arizona
Posts: 819
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Re: Do the 3:08's have to go???
I agree with start with the basics,tune up and all that maybe even a compression check is in order!!!!!And personally i believe a 700r would be good in youre situation!!!700r have a lower 1st gear which is what you need for that bass or jet boat!!!!And the od will sure help with mpg!!!!! I also never saw anything about tire size,assuming youre near stock size tire?Good luck and let us know what ya find!!!!!!!
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1971 c-10 1951 3100 chevy 1970 chevy c-30 Sold! Last edited by brianthelion02; 09-12-2007 at 07:29 PM. |
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#22 |
Registered User
Join Date: Sep 2006
Location: California
Posts: 11
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Re: Do the 3:08's have to go???
Gentlemen, want to thank all you for taking time to address my problem. Going to advance the snot out of it till she pings,lean the primaries and see how she runs. Good to hear from all you. Thanks a bunch.....
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#23 |
Project underway - finally.
Join Date: Feb 2007
Location: Greenville, SC
Posts: 493
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Re: Do the 3:08's have to go???
Do yourself a favor and make sure that the butterflies are open all the way under WOT. This is surprising, but it makes a BIG difference obviously.
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1972 GMC Pre-resto... awaiting allocated funding. |
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#24 |
Registered User
![]() Join Date: Feb 2004
Location: brownfield texas (west texas)
Posts: 1,936
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Re: Do the 3:08's have to go???
well i had a chevy 6 cylinder that lost all its get up and go and found out that i neeeded to change the advance kit, you can get a performance advance kit from auto zone,napa,etc(@$15) looks like two little dog legs and a bunch of different springs they go under the distributor cap, start with the lightest ones and if it pings go to the med, lighter the spring the more advance. when i changed mine they visualy looked great but the car got so bad it would bog itself going up a hill, after i swaped them out i could light up two 8 in tires with a tired 200 v6
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The Ghost 67 short wide full custom. 550 hp LSX, 4l80E, narrowed 9". Body dropped w/air ride! ........................ ___ .........________//__{\_____ ,,,,,,,/__(⊙)___//___/__(O)_/ @disciple2.rc 💪instagram💪 LED TAILS Last edited by Robznob11; 09-15-2007 at 11:24 AM. |
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#25 |
Junior Member
Join Date: Jul 2007
Location: Odenton, Md
Posts: 552
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Re: Do the 3:08's have to go???
welcome....and check your carb.
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going to sell this one...looking for a SWB project next. |
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