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Old 03-12-2016, 11:46 AM   #1
Ta2edjr
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help my brain hurts!

So I'm in the process of finishing my ls swap....little info before we get started.....72 c10 shortbed .completely stock lm7 completely stock 4l60e and 3.08 12 bolt rear.....I have freed up some extra truck fund money so to speak and I'm wanting to add a little more pep to this old trucks step. From what I have gathered a cam swap would be the best bang for the buck....but trying to find the perfect cam has ben a headache....my goals are still wanting to be able to drive the truck daily and still get good fuel mileage....I have Ben told by several that if I change my rear gear ratio I would have a better cam selection...so with that I ask would going to a 3.42 from a 3.08 really help in my selection of cams? Any and all help would be appreciated like always. Also would putting a stall in the trans help....like I said this will be a true daily driver. No weekend warrior I miss driving the truck it's ben down for almost 6 months now and it's killing me lol
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Old 03-12-2016, 03:50 PM   #2
mike16
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Re: help my brain hurts!

I think the 308 rear is limiting your pep. with an automatic and over drive and a 307 rear A cam would not be as effective. 336 or around 342 would be a good combo, again dpending what cam you use.

you will notice and miss the fuel economy when you change both the rear end gears and the cam. I know fuel is cheap right now but that wont last forever. think about enjoying, affordably, down the road, your old truck.

if after replacing gears and cam, your still not happy, then tire diameter is the last variable to influence. Always buy your tires last!
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Old 03-22-2016, 06:29 AM   #3
Ta2edjr
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Re: help my brain hurts!

Thanks Mike I'll be finishing up my swap first just to get a feel for how the truck runs and handles with the 5.3 and 4 spd auto..fuel mileage for me is a must so I might not go with a gear change...the previous power plant was a 355 and turbo 350 that would pass anything but a gas station. I loved the truck with the old small block in it but it killed me in gas and I couldn't keep my foot out of it so that didn't help much either...just want to find a happy medium between power and fuel mileage lol
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Old 03-22-2016, 01:04 PM   #4
steelhorse
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Re: help my brain hurts!

If you are planning on running 20s or any tire bigger than stock I would go with 3:73s the taller tire will offset your lower gear but still leave plenty of pep and the overdrive trans will keep RPMs in check.
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Old 03-22-2016, 01:25 PM   #5
67 chevelle
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Re: help my brain hurts!

Id drive it as is , but if you must , ls6 cam ,springs, and tune , plus 373 gears will up your powerband , and fuel consumption , most 4l60 transmissions came in trucks with lower gears [and taller tires] , so again if you must , Id do 3.73 gears and a posi first

seriously Id drive it as is
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68 Long Fleet , ly6 , turbo 350 , 3-5 drop , original paint , front discs
67 Small window , 7 foot bed , tweaked 6.0 LSX 2004R Medium Olive
58 Apache fleet , 235 , offy intake , dual exhaust , 4 on the floor , red/white
69 Long Fleet , Custom , 6.0, 4l60 , AC , Medium Olive

Last edited by 67 chevelle; 03-22-2016 at 01:31 PM.
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Old 03-22-2016, 02:51 PM   #6
XwalkerX
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Re: help my brain hurts!

learn from my mistake.
I have a 5.3 L33/4L60e swapped truck.
when I bought my truck I discovered that the rear end was SHOT. so I took the time to bump up from the 3.08 rear to a 3.42 with an eaton posi unit.

im just like you and I commute in my truck daily as well as a weekly trip to san diego which is 120 miles one way.

I turn approx 2100 rpm at 70mph which is nice but man I really wish I would have gone with 3.73 for that little extra pep out of the hole. too late for me now because I would have to basically start from scratch and buy a series 4 carrier posi unit along with the new gears.

as for power...I just got a tune from Justin at Blackbear Performance and I can certainly notice the difference since my MAF was reading 12% high and my shifts were a mess. def well worth the $250 for a live tune ($50 bucks off for law enforcement)

also im actually about to pull the trigger on a Texas Speed and Performance 224r cam.
224/224, .600"/.600", 112 LSA
TSP offers a kit option that comes with PAC1218 springs, hardened pushrods, timing gears/chain and bolt/gasket kit for $750

https://www.texas-speed.com/p-1157-t...ls1ls2ls6.aspx
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