Let's see who knows their Chevys. "305 vs Chevy 307" which i

Discussion in 'General Discussion' started by jetsetw31, Dec 20, 2013.

  1. Evan11

    Evan11 Royal Smart Person

    Joined:
    Apr 17, 2009
    Messages:
    1,295
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    I would prefer a 307 over a 305, because they are pre-smog & you'd have a better starting point IMO. If I was to get a 307, it would have to be a 67-71, b4 they starting cutting everything down.
     
    #11
  2. DRIVEN

    DRIVEN Comic Book Super Hero

    Joined:
    Apr 25, 2009
    Messages:
    3,139
    Likes Received:
    5
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    Don't forget that there was a change in the HP ratings method in '71-'72. So just because it was pre-'72 doesn't necessarily mean anything.
     
    #12
  3. thrasher

    thrasher Greasemonkey

    Joined:
    Nov 12, 2013
    Messages:
    120
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    When it comes to stock engines this is the correct answer of course.
    Now I see why they call you a "Royal Smart Person" :p
     
    #13
  4. clean8485

    clean8485 Royal Smart Person

    Joined:
    Dec 18, 2005
    Messages:
    1,258
    Likes Received:
    1
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    As far as I know, the highest horsepower rating for a 305TPI engine was 215HP, which was in either '85 or '86 in the IROC Camaro. Even if you look at the 350TPI engines, the highest horsepower rating for them was either 245 or 250HP, just before GM brought in the LT1 350 in the early '90s.
     
    #14
  5. olds307 and 403

    olds307 and 403 Royal Smart Person

    Joined:
    Oct 14, 2008
    Messages:
    1,246
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    The later versions of the TPI was 230 hp. Pretty sure the later Vortec was the same.
     
    #15
  6. 455'ed80Regal

    455'ed80Regal Greasemonkey
    Silver

    Joined:
    Nov 3, 2010
    Messages:
    161
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    Given a choice of what was produced during the production runs of each engine, for me, the choice is easy... 89-92 tpi 305
     
    #16
  7. gmparts

    gmparts Apprentice

    Joined:
    Jan 27, 2013
    Messages:
    61
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    Chevy 307 are just a punched out 283. The 307 started in 68 chevrolets
     
    #17
  8. DRIVEN

    DRIVEN Comic Book Super Hero

    Joined:
    Apr 25, 2009
    Messages:
    3,139
    Likes Received:
    5
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    I believe you're thinking about the 302 which has the 283's stroke with the 327's bore. The 307 is the opposite, essentially a stroked 283 -- or small bore 327. Whichever way you want to look at it.
     
    #18
  9. Brother Al

    Brother Al Greasemonkey

    Joined:
    Jan 26, 2010
    Messages:
    239
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    Exactly as stated above.... they used large journal 327 crank in a 283 block = Chevy 307 w/ 2.45" journals/3.875 in × 3.25 in bore.

    Also seems to be a bit of confusion here about the 307.

    GM had 2 different engines that displaced "307" cubic inches...
    Back before GM "Corporate Engines"... Each Division of GM made their own.

    Pre-"Corporate GM"
    Chevy 350 vs Pontiac 350 vs Olds 350 vs Buick 350
    Chevy 400 SBC vs Chevy 400 (402) BBC vs Pontiac 400 vs Olds 400 (not 403) vs Buick 401

    Chevy 307 IS NOT Olds 307.
    CHEVY 307ci SBC from '68-'73
    OLDS 307 from '80-'90

    The Chevy 307, like the later 305, was an "Economy" engine... unlike the 305, Chevy never made a "Performance Version" of the 307... they were daily driver motors with no real power to speak of. The cam profile was lame duck and it suffered from the same issue as early 305's... soft cam lobes that rounded out because Chevy cheapened out on the hardening process... IF you were building a 307 from scratch vs a 305 from scratch... the 307 has an edge because it can breathe easier, but dollar for dollar... its about the same... Most people drew the same conclusion from the 70's -80's about the Chevy 307, as people do between 1980's & now about the 305... yank it and drop in a 350 Chevy... You can get respectable power out of the Chevy 307, and you can get respectable power out of the 305, and for arguements sake, even the Olds 307... the Olds 307 costs considerably more to get power out of, but pound for pound, the Olds has a very healthy Torque edge.
    Ultimately, It all depends what you want, what you need, & how much you want to spend to get there.

    In Stock Form: Any Year 307 vs Any Year 305... (including Olds 307)
    IMHO... The 1985 TPI 305 is the most potent stock version...
    Why?
    Chevy simply used the L69 Short Block/Exhaust and put the TPI set-up on top... the reason the numbers drop in '86 is because Chevy went to a different set-up/less potent shortblock set-up, w/a lesser EFI cam. They squeezed more power out of the last few years with a better injection set-up and ECM/PROM, and a roller set-up...

    The L69 used flat-top pistons w/ 4 valve reliefs and the most potent "smog" hydraulic cam profile ever used (better than most non-smog profiles even), large cat, large dia Exhaust manifolds/Y-pipe/exhaust, better ECM/PROM... The biggest "failure" of the combo was the lack of better heads/squeezing in larger valves... but compared when compared to the LG4, the L69/'85 LB9 are noticably more aggressive... (this being true for well-maintained, lower mileage examples in stock form)... I will use the difference between my old '86 Firebird LG4/700R4/2:73:1 gears, vs a friend's '87 LG4 Formula/T5/3:42, vs my '84 Recaro T/A /T5/3:73... even between the '87 Formy and my '84 Recaro... the power comes on faster in the Recaro T/A... the slight axle ratio cannot account for it alone. Added to this is the extra weight found in the Recaro because it was the Flagship Model (IE Loaded with options and sound deadening) .... the L69 is simply just more aggressive thanks to its cam and larger exhaust... the 3:73 axle ratio and T-5 only add to the fun.

    1982 F-Body LG4 305: 8.5:1 145 HP @4000 RPM, 240 ft/lb @2000 RPM (Q-Jet 4bbl)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1982 F-Body LU5 305 (Crossfire): 8.5:1 165 HP @4200 RPM, 240 ft/lb @2400 RPM (Crossfire EFI)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1983 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2000 RPM (Q-Jet 4bbl)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1983 F-Body LU5 305: 9.5:1 175 HP @4200 RPM, 250 ft/lb @2800 RPM (Crossfire Dual TBI)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1985 F-Body LG4 305: 9.5:1 155 HP @4200 RPM, 245 ft/lb @2000 RPM (Q-Jet 4bbl)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1985 F-Body LB9 305: 9.5:1 215 HP @4400 RPM, 275 ft/lb @3200 RPM (TPI 305)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1986 F-Body LG4 305: 9.5:1 165 HP @4400 RPM, 250 ft/lb @2000 RPM (Q-Jet 4bbl)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1986 F-Body LB9 305: 9.5:1 190 HP @4000 RPM, 285 ft/lb @2800 RPM (TPI 305)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1986 F-Body L98 350: 9.5:1 220 HP @4200 RPM, 320 ft/lb @3200 RPM (TPI 350)
    ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    1983 -'86 F-Body L69 305: 9.5:1 190 HP @4800 RPM, 240 ft/lb @3200 RPM* (Q-Jet 4bbl H/O)

    PISTONS:
    1982 -'83 F-Body LU5: GM PN: 364702 8.6:1 CR (dished)
    1982 -'84 F-Body LG4: GM PN: 364702 8.6:1 CR (dished)
    1985 -'86 F-Body LG4: GM PN: 14081291 9.5:1 CR (flat) 4 valve reliefs
    1983 -'86 F-Body L69: GM PN: 14081291 9.5:1 CR (flat) 4 valve reliefs
    1985 -'86 F-Body LB9: GM PN: 14081291 9.5:1 CR (flat) 4 valve reliefs
    1987 F-Body LG4: GM PN: 14094013 CR (flat) 4 valve reliefs
    1987 -'92 F-Body LB9: GM PN: 14094013 CR (flat) 4 valve reliefs
    1988 -'92 F-Body LO3: GM PN: 14094013 CR (flat) 4 valve reliefs

    CAMSHAFT:
    1982 -'83 F-Body LU5: GM PN: 14088839 Hyd. Flat Tappet - Duration @ .050": 194/202 - Max Lift .383/.401 - 112 - Idle: 650 rpm
    1982 -'86 F-Body LG4: GM PN: 14088841 Hyd. Flat Tappet - Duration @ .050": 178/194 - Max Lift .350/.385 - 108 - Idle: 650 rpm "Peanut Cam"
    1983 -'86 F-Body L69: GM PN: 14088843* Hyd. Flat Tappet - Duration @ .050": 202/206 - Max Lift: .403/.415 - 115 - Idle: 650 rpm *Note: L69 cam is not the same as the L81 "929" cam.
    * GM Replacement PN: 12523897

    1985 F-Body LB9: GM PN: 14088843 Hyd. Flat Tappet - Duration @ .050": 202/206 - Max Lift: .403/.415 - 115 - Idle: 650 rpm
    1986 F-Body LB9: GM PN: 14094097 Hyd. Flat Tappet - Duration @ .050": 178/194 - Max Lift: .350/.385 - 109 - Idle: 650 rpm
    1987 F-Body LG4/LB9-AT: GM PN: 14093630 Roller Cam - Duration @ .050": ???/???- Max Lift: ???/??? - ???- Idle: 650 rpm
    1987 F-Body LB9-T5: GM PN: 14093643 Roller Cam - Duration @ .050": 202/207 - Max Lift: .404/.415 114.5 - Idle: 650 rpm
    1988 -'89 F-Body LB9-AT: GM PN: 10088155 Roller Cam - Duration @ .050": 179/194 - Max Lift: .350/.384 - 109 - Idle: 650 rpm1982 -'83 F-Body LU5: GM PN: 14088839 Hyd. Flat Tappet - Duration @ .050": 194/202 - Max Lift .383/.401 - 112 - Idle: 650 rpm
    1982 -'86 F-Body LG4: GM PN: 14088841 Hyd. Flat Tappet - Duration @ .050": 178/194 - Max Lift .350/.385 - 108 - Idle: 650 rpm "Peanut Cam"
    1983 -'86 F-Body L69: GM PN: 14088843* Hyd. Flat Tappet - Duration @ .050": 202/206 - Max Lift: .403/.415 - 115 - Idle: 650 rpm *Note: L69 cam is not the same as the L81 "929" cam.
    * GM Replacement PN: 12523897

    1985 F-Body LB9: GM PN: 14088843 Hyd. Flat Tappet - Duration @ .050": 202/206 - Max Lift: .403/.415 - 115 - Idle: 650 rpm
    1986 F-Body LB9: GM PN: 14094097 Hyd. Flat Tappet - Duration @ .050": 178/194 - Max Lift: .350/.385 - 109 - Idle: 650 rpm
    1987 F-Body LG4/LB9-AT: GM PN: 14093630 Roller Cam - Duration @ .050": ???/???- Max Lift: ???/??? - ???- Idle: 650 rpm
    1987 F-Body LB9-T5: GM PN: 14093643 Roller Cam - Duration @ .050": 202/207 - Max Lift: .404/.415 114.5 - Idle: 650 rpm
    1988 -'89 F-Body LB9-AT: GM PN: 10088155 Roller Cam - Duration @ .050": 179/194 - Max Lift: .350/.384 - 109 - Idle: 650 rpm
    1988 -'89 F-Body LB9-T5: GM PN: 10066049 Roller Cam - Duration @ .050": 207/213 - Max Lift: .415/.430 - 117 - Idle: 650 rpm
    1988 -'92 F-Body LO3: GM PN: 10088155 Roller Cam - Duration @ .050": 179/194 - Max Lift: .350/.384 - 109 - Idle: 650 rpm
    1990 -'92 F-Body LB9/L98: GM PN: 10111773 Roller Cam - Duration @ .050": 202/207 - Max Lift: .413/.428 - 114.5 - Idle: 650 rpm

    HEADS:
    1982 -'83 F-Body LG4: GM PN: 14022601 int: 1.76/ exh: 1.46, 58cc chambers, 178cc runners, Flat Tappet
    1983 -'86 F-Body LG4: GM PN: 14022601 int: 1.84/ exh: 1.50, 58cc chambers, 178cc runners, Flat Tappet
    1983 -'86 F-Body LG4: GM PN: 14014416 int: 1.84/ exh: 1.50, 58cc chambers, 178cc runners, Flat Tappet
    1983 -'86 F-Body L69: GM PN: 14014416 int: 1.84/ exh: 1.50, 58cc chambers, 178cc runners, Flat Tappet
    1987 -'88 Monte SS L69: GM PN: 14101081 int: 1.84/ exh: 1.50, 58cc chambers, 178cc runners, Flat Tappet, some-Roller Cam? - center bolt

    (FYI: ALL INFO ABOVE IS INFO I COMPILED AND HAVE POSTED ON A NUMBER OF WEBSITES, I cut-copy-pasted here)
     
    #19
  10. thrasher

    thrasher Greasemonkey

    Joined:
    Nov 12, 2013
    Messages:
    120
    Likes Received:
    0
    Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

    Brother Al, you just put entirely too much time into a 307 :)
     
    #20
Loading...

Share This Page

VigLink badge