307 v8?!?!?!

Discussion in '1967-1972' started by BAgmc90, Aug 22, 2009.

  1. BAgmc90

    BAgmc90 Member

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    Ok so i just traded my trailer for this 68 GMC longbed.. and it has a 307 V8... anyone know what i can do with this motor? its not blown or anything.. jus a stock v8... but i had a 305 in my old truck.. and is it the same motor? or should i put like a 350 in it.. it doesnt need alot of work(the truck) but any input on what i should do to it??
     
  2. 72c102494

    72c102494 Member

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    Nov 5, 2009
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    keep it!!

    well i have a 72 c10 with a 307 also. the motor is very strong. i wouldnt suggest putting a 350 only because the 307 was used in few years of the c10. it is a great motor with alot of power. there is alot that can be done with it, a nice cam, 4 barrel carb, whatever you want. hope this helps
     
  3. 2tons of fun

    2tons of fun Member

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    i would say the exact opposite, toss that pos.

    they are a small piston with a 350 stoke. the thing that made the 302 so good was a medpiston with a shorter stroke, makes a good high rpm motor. the 305/307 are the opposite. small piston make small chambers and small fire.

    you would be miles ahead to spend any money on a 350 and it wil use all the same stuff.
     
  4. GonicGM

    GonicGM Member

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    Nope, a 305 has the same stroke as a 350. The 307 has the same stroke as a 327. i.e. the 307 is a stroker 283, 283 bore with 327 stroke. So believers in a stroker motor, 383 (350 with a 400 crank), this is the same concept, just smaller. 307's got a bad rap in the day, two barrel motor, small valve, low compression, bad (soft) camshafts.

    If the motor has good compression, no unusual noises, it is a good candidate to wake up with minor mods.
     
  5. capev86

    capev86 Member

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    i am not a big fan of the 307, i'd prefer the longer stroker 305 in a truck, but thats what my 72 burb came with. i have a bad boy 406sbc i will be dropping in eventually and i plan to ditch that stupid rochester 2 barrel in favor of a quadrajet real soon (better economy AND power). i like hondas, but an american truck is better off with a stroker motor than a screamer that has no grunt. give me the power in the reasonable rpm range so i can use it on the street and pulling loads. if i didn't have that 406, i might build a stroker out of the 307. but even with the 307, 4.57 gears are a little steep, so i'm doing the third member boogie in the rear axle and going to a 4.10 gear and will eventually add the factory overdrive unit to the saginaw 3 on the tree. 10mpg is pitiful with a puny little 307. i've gotten 16-18 out of that 406 when it was in my dad's 84 burb (2wd, quadrajet, 700-r4, 3.73 gears)
     
  6. JonathonPearson

    JonathonPearson Member

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    307

    I have a 307 in my 1970 c10 it is a solid motor i took it out tore it down and inspected all the parts thouroghly got the heads reworked new aluminum intake holley 4 barrel headers ud be suprised how just this wakes up a 42 yo motor. ans besides everybody has a 350 y not go for somthing a little diffrent.
     
  7. Lakeroadster

    Lakeroadster Member

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    Chevy smallblock v-8 bore and stroke

    262 = 3.671" x 3.10" (Gen. I, 5.7" rod)
    265 = 3.750" x 3.00" ('55-'57 Gen.I, 5.7" rod)
    265 = 3.750" x 3.00" ('94-'96 Gen.II, 4.3 liter V-8 "L99", 5.94" rod)
    267 = 3.500" x 3.48" (Gen.I, 5.7" rod)
    283 = 3.875" x 3.00" (Gen.I, 5.7" rod)
    293 = 3.779" x 3.27" ('99-later, Gen.III, "LR4" 4.8 Liter Vortec, 6.278" rod)
    302 = 4.000" x 3.00" (Gen.I, 5.7" rod)
    305 = 3.736" x 3.48" (Gen.I, 5.7" rod)
    307 = 3.875" x 3.25" (Gen.I, 5.7" rod)
    325 = 3.779" x 3.622" ('99-later, Gen.III, "LM7", "LS4 front wheel drive V-8" 5.3 Liter Vortec, 6.098" rod)
    327 = 4.000" x 3.25" (Gen.I, 5.7" rod)
    345 = 3.893" x 3.622" ('97-later, Gen.III, "LS1", 6.098" rod)
    350 = 4.000" x 3.48" (Gen.I, 5.7" rod)
    350 = 4.000" x 3.48" ('96-'01, Gen. I, Vortec, 5.7" rod)
    350 = 3.900" x 3.66" ('89-'95, "LT5", in "ZR1" Corvette 32-valve DOHC, 5.74" rod)
    364 = 4.000" x 3.622" ('99-later, Gen.III, "LS2", "LQ4" 6.0 Liter Vortec, 6.098" rod)
    376 = 4.065" x 3.622" (2007-later, Gen. IV, "L92", Cadillac Escalade, GMC Yukon)
    383 = 4.000" x 3.80" ('00, "HT 383", Gen.I truck crate motor, 5.7" rod)
    400 = 4.125" x 3.75" (Gen.I, 5.565" rod)
    427 = 4.125" x 4.00" (2006 Gen.IV, LS7 SBC, titanium rods)
     
  8. mike 16

    mike 16 Member

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    I have a 72 with a 307, its as good as any small block in stock configuration. often times the 307 has high nickle and high tin content casting. even with the 350 you dont always get that.

    if its stock, and runs good leave it alone. theres nothing wrong with it. its no hot rod motor nor is it a foundation for one but it was never intended to be that way anyway so dont blame the engine.

    if it runs good keep it, there will more time when you wish you kept it than time when you need the extra hp of a 350 or a bbc.

    if your looking for gas milage your better off trading your 3.70 rear for a 3.08 rear.

    myself, and two friends have a six, a 307 and a 4bbl 350 all with the 370 rear and we all get about 13 mpg. another friend has a 350, automatic and a 308rear, he gets 17-19 mpg.

    regardless, theres nothing wrong with a 307 engine. depending on how many miles is on it, I would reseal the motor, put new timing set and oil pump in it and an hei and call it good for another 60 k miles.
     
  9. vwnate1

    vwnate1 Member

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    307 cid v-8

    What Mike said ! .

    Plus , this is a " smog " engine so the original cam profile is slightly (3°) retarded from where it oughta be ~ it's fairly simple to replace the old cam & lifters , no need for ' racing ' crap , once it has a good 3/4 ton truck cam in there with new timing chain and gears , it'll be a peppy mill with decent fuel economy , nothing to sort at with $4.00 / gallon fuel co$t$ .
     

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