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Old 04-09-2007, 04:28 PM
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305 heads on 350 question

ive got a 66 cutlass with a chevy 350(i know) i just found out the heads are 305 heads.(376450 casting) this engine has a comp 270 cam,edelbrock aluminum intake and edelbrock 600cfm carb with a 4 speed tranny.full tube headers,(im thinking about stock exh manifolds though,, ive got the intake off, should i just pull these heads and chunk them or does it matter? ive heard horror stories of blown head gaskets and choked 350's . it seems to run good but i dont want to damage my motor if i can just pull them off and put on some camel humps or equivalent. thanks in advance.

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Old 04-09-2007, 05:29 PM
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get rid of those 376450 castings if you want a 305 head use the #416 other than that id say #882 or #461 350 heasds.
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Old 04-09-2007, 05:37 PM
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save some money and try a set of runable salvage yard vortec heads, you could get valve covers and rocker arms at salvage yard too. heres a guide to what is needed.





http://www.2quicknovas.com/vortecheads.html


Mustangsaly
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Old 04-09-2007, 09:02 PM
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l69 305 heads are pretty good aint they 54cc chambers
Shane
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Old 04-09-2007, 09:44 PM
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would a comp 270 cam equalize the extra compression to help with detonation?
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Old 04-09-2007, 10:01 PM
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If it runs I'd leave it untill you can get a nice set of aftermarket heads- if it aint broke don't fix it, unless you can improve it.
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Old 04-09-2007, 11:08 PM
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Don't use 305 heads on a 350

Quote:
Originally Posted by pi71
ive got a 66 cutlass with a chevy 350(i know) i just found out the heads are 305 heads.(376450 casting) this engine has a comp 270 cam,edelbrock aluminum intake and edelbrock 600cfm carb with a 4 speed tranny.full tube headers,(im thinking about stock exh manifolds though,, ive got the intake off, should i just pull these heads and chunk them or does it matter? ive heard horror stories of blown head gaskets and choked 350's . it seems to run good but i dont want to damage my motor if i can just pull them off and put on some camel humps or equivalent. thanks in advance.
The only way you can use 305 heads, if you have them fly cut. You can not , I repeat...Can not! use 305 heads just by bolting them on. The engine will detonate and run severely hot under heavy loads. I learned this lesson around 20 years ago. Mike
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Old 04-09-2007, 11:17 PM
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i do have 305 heads on my car at present, but it backfires thru the carb and bogs at takeoff.. (it had two holley 450s with a tunnel ram and i know that was part of it but i think im gonna chunk the crappy 305 heads and get some camel hump heads..anyone want some runnin 305 heads?
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Old 04-10-2007, 09:41 AM
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ok i just picked up some 291 casting camel hump heads, these should flow a little better than the 305 heads!!
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Old 04-10-2007, 10:06 AM
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Good deal, the 305 heads are only choking the engine to death. The cam couldn`t make up for the lack of flow and flow is power.
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Old 04-10-2007, 11:04 AM
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Quote:
Originally Posted by AutoBodyGod
The only way you can use 305 heads, if you have them fly cut. You can not , I repeat...Can not! use 305 heads just by bolting them on. The engine will detonate and run severely hot under heavy loads. I learned this lesson around 20 years ago. Mike
ive used them without any detonation problem, they were 416 castings
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Old 04-10-2007, 01:06 PM
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Quote:
Originally Posted by runn141
ive used them without any detonation problem, they were 416 castings
how is your engine up past 4000? mine is a dog with the 305 heads
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Old 04-10-2007, 02:05 PM
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"do You Have Them Now?" They Are On Their Way.. Cant Wait To See The Difference. They Were On My Dads 350 .. Ran Great!!
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Old 04-10-2007, 03:17 PM
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Quote:
Originally Posted by pi71
how is your engine up past 4000? mine is a dog with the 305 heads
pretty good all the way to 6300rpm
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Old 04-10-2007, 04:12 PM
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I had those 450 casting 305 heads on a 350. A few weeks ago, I took it out cause it blew the head gasket. This was the second blown head gasket in one year. The motor actually felt strong off the line. But as soon as you hit 4,000 rpm it fell flat on its face... I had to use 91 octane to be safe too. Overall I was dissapointed and I would never do that again... my2c.
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