305 vortec heads

deep · 03-27-2007, 10:54 PM

I have used 350 vortec heads in the past with great results, but found some 305 vortec heads and was wondering if they will perform as well as the 350's?also I noticed the 305 heads have a 58cc chamber,and was wondering if I would still be able to run pump gas with a 350 flat top piston?thanks!

greg fulk · 03-28-2007, 01:46 AM

if you use a thick head gasket maybe. 58cc on a 350 will make it like better then 11to1. as to the "vortec" 305 heads....? do you mean center bolt valve cover heads? or the late 90's vortec truck heads?

novamoation

deep · 03-28-2007, 11:09 PM

yeah, its center bolt valve covers, and they supposedly come off a late 90's model pick up.

greg fulk · 03-29-2007, 03:41 AM

deep it's one of those deals that "IF" you can get them cheap try them! a head gasket set from "the-zone" is about .050 so it may work fine.

novamoation

crazyponcho · 04-16-2008, 01:26 PM

a word of caution, if you are using flat tops and just using a thick gasket to drop compression you may just make the engine even more detonation sensitive since you are loosing all of your quench. You would be better of using a dished piston or grinding the combustion chambers bigger and running a quench of .038 to .040. It will be less detonation sensitive and probably make an extra pony or two over having a a quench of say .050

Adger Smith · 04-17-2008, 06:25 AM

I have a 305 head combo I've been using on some circle track limited engines. Better check the out side water passages (spark plug side) & the fire ring of the gasket. A lot of these heads are cast where the fire ring of the 350 bore gasket hangs over, or almost into, the water passage & leaks. Otherwise they will work. I do hope you mean the head WITHOUT the swirl ramp under the intake valve. That is a true Vortec. You are wasting your time using the heads with the swirl ramps. They quit flowing @ around .425 lift. They are great for what they are designed, low end power in trucks & cars. Max swirl. You will never be able to run them on a 350 with pump gas. About 11-1. I always do an unshroud on the valve pockets to pick up the flow & they end up around 66-68 cc. The flow is worth more than the compression.

03-27-2007, 10:54 PM	#1
deep Junior Member Join Date: Feb 2007 Posts: 6 Likes: 0 Liked 0 Times in 0 Posts	305 vortec heads I have used 350 vortec heads in the past with great results, but found some 305 vortec heads and was wondering if they will perform as well as the 350's?also I noticed the 305 heads have a 58cc chamber,and was wondering if I would still be able to run pump gas with a 350 flat top piston?thanks!

03-28-2007, 01:46 AM	#2
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	if you use a thick head gasket maybe. 58cc on a 350 will make it like better then 11to1. as to the "vortec" 305 heads....? do you mean center bolt valve cover heads? or the late 90's vortec truck heads? novamoation __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

03-29-2007, 03:41 AM	#4
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	deep it's one of those deals that "IF" you can get them cheap try them! a head gasket set from "the-zone" is about .050 so it may work fine. novamoation __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

04-16-2008, 01:26 PM	#5
crazyponcho Junior Member Join Date: Mar 2008 Posts: 9 Likes: 0 Liked 0 Times in 0 Posts	Re: 305 vortec heads a word of caution, if you are using flat tops and just using a thick gasket to drop compression you may just make the engine even more detonation sensitive since you are loosing all of your quench. You would be better of using a dished piston or grinding the combustion chambers bigger and running a quench of .038 to .040. It will be less detonation sensitive and probably make an extra pony or two over having a a quench of say .050

04-17-2008, 06:25 AM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: 305 vortec heads I have a 305 head combo I've been using on some circle track limited engines. Better check the out side water passages (spark plug side) & the fire ring of the gasket. A lot of these heads are cast where the fire ring of the 350 bore gasket hangs over, or almost into, the water passage & leaks. Otherwise they will work. I do hope you mean the head WITHOUT the swirl ramp under the intake valve. That is a true Vortec. You are wasting your time using the heads with the swirl ramps. They quit flowing @ around .425 lift. They are great for what they are designed, low end power in trucks & cars. Max swirl. You will never be able to run them on a 350 with pump gas. About 11-1. I always do an unshroud on the valve pockets to pick up the flow & they end up around 66-68 cc. The flow is worth more than the compression. __________________ Adger Smith (Former SS) Last edited by Adger Smith; 04-17-2008 at 06:27 AM. Reason: sp

03-28-2007, 11:09 PM	#3
deep Junior Member Join Date: Feb 2007 Posts: 6 Likes: 0 Liked 0 Times in 0 Posts	yeah, its center bolt valve covers, and they supposedly come off a late 90's model pick up.