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

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Evan's 85
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby Evan's 85 on Sun Dec 22, 2013 12:43 pm

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.
Evan

1985 Olds Cutlass : Hurst/Olds Tribute
83-84 H/O hood, spoiler, and wheels..79 H/O dual gate shifter
1969 350 SBO #5 heads, TH-350 trans, 2.73 posi rear

1978 Ford F-250 4x4
400, C6

1965 Chevy C-10 short step side
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DRIVEN
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby DRIVEN on Sun Dec 22, 2013 1:05 pm

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.
'79 Cutlass - 305, '66 El Camino - 400, '35 Ford Sedan - DOHC 4.6, '35 Ford pickup - 283, '72 510 wagon - Quad4, '82 Goldwing - 1100

thrasher
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby thrasher on Sun Dec 22, 2013 2:13 pm

DRIVEN wrote:305 vs 307? Can't really compare the two. There was never even a mild performance version of the 307.


When it comes to stock engines this is the correct answer of course.
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clean8485
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby clean8485 on Mon Dec 23, 2013 12:38 pm

[quote="seawolf18"][quote="clean8485"]In what application did you get a 305 that was rated at 250HP?[/quote]

305 TPI[/quote]
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.

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olds307 and 403
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby olds307 and 403 on Mon Dec 23, 2013 3:13 pm

The later versions of the TPI was 230 hp. Pretty sure the later Vortec was the same.
88 Cutlass Supreme Classic, Mild Olds 350, 2004R, 3.42 open for now....94 chev Z71 4x4, TBI 76 350 Olds, 5A heads,A4,204/214 cam,Sanderson's and duals, rebuilt 4L60E,3.73 gov lock, 2010 Challenger SE, Stone White, leather, 18" wheels, 2000 Dodge Dakota Sport Club Cab 4x4, 3.9 v6 and 3.92 no slip.

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455'ed80Regal
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby 455'ed80Regal on Mon Dec 23, 2013 9:01 pm

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

2nd owner of 1980 Regal w/118xxx, 3.8L, T350, 2.41 gears, factory buckets, floor shift, center console and gage package.

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gmparts
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby gmparts on Mon Dec 23, 2013 9:36 pm

Chevy 307 are just a punched out 283. The 307 started in 68 chevrolets

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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby DRIVEN on Mon Dec 23, 2013 10:24 pm

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.
'79 Cutlass - 305, '66 El Camino - 400, '35 Ford Sedan - DOHC 4.6, '35 Ford pickup - 283, '72 510 wagon - Quad4, '82 Goldwing - 1100

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Brother Al
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby Brother Al on Tue Dec 24, 2013 12:16 pm

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)
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1982 F-Body LU5 305 (Crossfire): 8.5:1 165 HP @4200 RPM, 240 ft/lb @2400 RPM (Crossfire EFI)
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1983 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2000 RPM (Q-Jet 4bbl)
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1983 F-Body LU5 305: 9.5:1 175 HP @4200 RPM, 250 ft/lb @2800 RPM (Crossfire Dual TBI)
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1984 F-Body LG4 305: 8.5:1 150 HP @4000 RPM, 240 ft/lb @2400 RPM (Q-Jet 4bbl)
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1985 F-Body LG4 305: 9.5:1 155 HP @4200 RPM, 245 ft/lb @2000 RPM (Q-Jet 4bbl)
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1985 F-Body LB9 305: 9.5:1 215 HP @4400 RPM, 275 ft/lb @3200 RPM (TPI 305)
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1986 F-Body LG4 305: 9.5:1 165 HP @4400 RPM, 250 ft/lb @2000 RPM (Q-Jet 4bbl)
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1986 F-Body LB9 305: 9.5:1 190 HP @4000 RPM, 285 ft/lb @2800 RPM (TPI 305)
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1986 F-Body L98 350: 9.5:1 220 HP @4200 RPM, 320 ft/lb @3200 RPM (TPI 350)
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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)
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Re: Let's see who knows their Chevys. "305 vs Chevy 307" whi

Postby thrasher on Tue Dec 24, 2013 2:10 pm

Brother Al, you just put entirely too much time into a 307 :)

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