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#884998 - 07/16/11 06:33 PM Will 350 heads work on a 305 block?
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
Will 350 heads work on a 305 block?

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#884999 - 07/16/11 06:42 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
88ss408 Offline
Member

Registered: 08/13/07
Posts: 1359
Loc: miramichi,new-brunswick
the short anser yes.
but if your using a stock block your compression will be low. as the 305 heads have 58cc chambers and 350 heads have 64cc(for performance heads) and 76cc(for smog heads)
but the 64cc head can be miled.030 for a 59cc chamber.
_________________________
1988 monte carlo ss 408 sbc 11:1 compression a.f.r.195cc heads accel ignition system comp cams .507/.510 air gap intake 800cfm edelbrock carb th350 trans 3000 stall torque headman headers 3" dual super 40's 3.73:1 limited slip
-----------------------------------------------------
1984 monte carlo cs 400,headers,th250c,air gap intake

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#885008 - 07/16/11 06:58 PM Re: Will 350 heads work on a 305 block? [Re: 88ss408]
foggerSS87 Offline
Member

Registered: 05/19/09
Posts: 451
Loc: chicago Illinois
it depends how big the valves are on the 350 heads
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87ss. lq4 with 78mm turbo, th350, 3800 stall, 3.25 9"

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#885012 - 07/16/11 07:13 PM Re: Will 350 heads work on a 305 block? [Re: foggerSS87]
MONTEBOSS Offline
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Registered: 06/28/11
Posts: 98
Loc: Wyoming Michigan
This is something I was wondering myself.

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#885015 - 07/16/11 07:19 PM Re: Will 350 heads work on a 305 block? [Re: MONTEBOSS]
ss4ever Offline
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Registered: 12/05/03
Posts: 12748
Loc: Shelbina, Missouri
Been there before, as stock replacement you should be ok but if your 350 heads have 202 valves and a big lift then you could run in to some problems. Personally you would be better off to find another set of 305 heads OR you could find a set of Corvette TPI Aluminum heads which are 58cc heads and they will work fine on a 305.
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1972 Monte Carlo, LS1/4L60E

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#885019 - 07/16/11 07:44 PM Re: Will 350 heads work on a 305 block? [Re: ss4ever]
BuzzLOL Offline
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Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
. Yes, the 2.02/1.60 valves get seriously shrounded in small 305" cylinder bores... and even bigger valves may not even clear the bores...

. Most basic/truck/marine 350's since 1971 will have the big 76cc chambers... as do 400's... even though they will all bolt on... and the 305" engine will run with them... but like a 1949 engine...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885021 - 07/16/11 07:50 PM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
ok. So its best not to get 350 heads on a 305 unless they have a serin valve sizes correct.?
The 350 heads numbers were gm6 878450 028.
Should i just rebuild my 305 heads?

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#885023 - 07/16/11 07:54 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
.. Depends on what your intentions for the engine are...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885025 - 07/16/11 08:00 PM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208

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#885042 - 07/16/11 10:01 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
.. Looks like a great price if they have the 10K miles claimed... but you need the engine size they came on or preferrably the casting numbers (they may be two different castings from a rebuilder) to see what they really are... also, since this is CraigList, make sure you will actually get the heads when paying...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885047 - 07/16/11 10:09 PM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
he said they came off a 350. and the numbers on them were gm 6 878450 028

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#885053 - 07/16/11 11:11 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
.. Are they GM/Chevy heads? I don't see anything close to those casting numbers listed...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885070 - 07/17/11 12:52 AM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
GM..
And i looked them up online , but i couldnt find a thing

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#885075 - 07/17/11 01:48 AM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
4893fei Offline
Member

Registered: 01/22/11
Posts: 469
Loc: 208
I think im going to just rebuild my stock 305 heads.
Did some research on the 350 heads on a 305 block. Not the best ideal.

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#885091 - 07/17/11 08:59 AM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
88ss408 Offline
Member

Registered: 08/13/07
Posts: 1359
Loc: miramichi,new-brunswick
for stock chevy heads the 416 or 113 are the best heads for a 305.
and if you want to go vortec theres the 059 and 062 (but the 062 will have to be milled)
_________________________
1988 monte carlo ss 408 sbc 11:1 compression a.f.r.195cc heads accel ignition system comp cams .507/.510 air gap intake 800cfm edelbrock carb th350 trans 3000 stall torque headman headers 3" dual super 40's 3.73:1 limited slip
-----------------------------------------------------
1984 monte carlo cs 400,headers,th250c,air gap intake

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#885107 - 07/17/11 11:59 AM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
Originally Posted By: 4893fei
I think im going to just rebuild my stock 305 heads.
Did some research on the 350 heads on a 305 block. Not the best ideal.


.. The -113 aluminum heads from 'Vette and ZZx/ZZ1-ZZ4 350's are 58cc combustion chambers like 305 heads and thus work without milling mods... they support up to about 385 HP... there may be some on Ebay/CL...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885134 - 07/17/11 02:26 PM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
Ok thanks for the help.
I will have to do some reseach and find some.

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#885137 - 07/17/11 02:37 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
4893fei Offline
Member

Registered: 01/22/11
Posts: 469
Loc: 208

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#885186 - 07/17/11 06:53 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
88ss408 Offline
Member

Registered: 08/13/07
Posts: 1359
Loc: miramichi,new-brunswick
they are the heads that came on 350 crossfire injection corvettes in the early 80's they are also the heads that made its way to the ss monte carlo's 305 ho.they are a good head.
_________________________
1988 monte carlo ss 408 sbc 11:1 compression a.f.r.195cc heads accel ignition system comp cams .507/.510 air gap intake 800cfm edelbrock carb th350 trans 3000 stall torque headman headers 3" dual super 40's 3.73:1 limited slip
-----------------------------------------------------
1984 monte carlo cs 400,headers,th250c,air gap intake

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#885191 - 07/17/11 07:13 PM Re: Will 350 heads work on a 305 block? [Re: 4893fei]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5549
Loc: Toledo, Ohio
.. Those are priced EACH I believe... may have the smaller 305 1.84" intake valves... although that place can prolly put any size in... like 1.94" usually found in 350's... may have the bigger 64cc combustion chambers of 350's...

.. Your old heads may be the same ones... may be able to get the old ones redone locally for less... ask around at local car shows...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#885329 - 07/18/11 03:57 PM Re: Will 350 heads work on a 305 block? [Re: BuzzLOL]
4893fei Offline
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Registered: 01/22/11
Posts: 469
Loc: 208
Thats wat i as thinking to.But i do all my work myself.

Has body rebuilt there heads.polishing and cleaning.something like that.

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