Vortec heads on a 305
#1
Vortec heads on a 305
Hey guys I found a set of cheap vortec heads and was gonna use them for a new motor build. The new motor won't be started for a while so I was gonna put the vortec heads on the 305 in it now. Can it be done fairly easily and kinda cheap? Can I put a carb on a vortec intake? And with the stock cam will any extra power be made?
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Re: Vortec heads on a 305
You can run vortecs on a 305, theres alot of info out there, people have done it.
two main things; you need a vortec specific intake manifold, and just bolting stock heads onto your 305 will lower compression. Need to usually have them milled to make the combustion chamber smaller which will raise compression back up.
two main things; you need a vortec specific intake manifold, and just bolting stock heads onto your 305 will lower compression. Need to usually have them milled to make the combustion chamber smaller which will raise compression back up.
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Car: 1983 G20 Chevy
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Re: Vortec heads on a 305
You can run vortecs on a 305, theres alot of info out there, people have done it.
two main things; you need a vortec specific intake manifold, and just bolting stock heads onto your 305 will lower compression. Need to usually have them milled to make the combustion chamber smaller which will raise compression back up.
two main things; you need a vortec specific intake manifold, and just bolting stock heads onto your 305 will lower compression. Need to usually have them milled to make the combustion chamber smaller which will raise compression back up.
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Re: Vortec heads on a 305
You'll need to mill .030 to .040 off the decks to get them back into the 58cc range which will then make them likely unusable on a 350 later.Like was said above,find a set L30/305 059 heads.They don't have the fastburn chamber of the 906/062,but they flow in the 220 cfm range.We've also used them on older 307 builds as well.Great heads for an iron OEM head.
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#8
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Re: Vortec heads on a 305
I've used them on a 305 WITHOUT milling them. Stock 305 heads have chambers about 58cc. Vortecs are listed as having 64cc chambers, but if you take the time to cc them you'll find they're actually around 62cc plus change. Not enough of a difference I felt like milling them, so I threw them on as-is. They absolutely blew the stock heads into the weeds, performance-wise, despite the slightly lower compression.
Note, I was using them on a 305 with factory flattop pistons, so I was starting with 9.5:1 compression to begin with. Probably low 9s once the stock Vortecs were bolted up top. The engine didn't care about the slight loss of compression. The Vortecs still made more power everywhere in the RPM range and didn't nose-over on the top end like the stock heads.
Note, I was using them on a 305 with factory flattop pistons, so I was starting with 9.5:1 compression to begin with. Probably low 9s once the stock Vortecs were bolted up top. The engine didn't care about the slight loss of compression. The Vortecs still made more power everywhere in the RPM range and didn't nose-over on the top end like the stock heads.
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Vortec heads on a 305
I've used them on a 305 WITHOUT milling them. Stock 305 heads have chambers about 58cc. Vortecs are listed as having 64cc chambers, but if you take the time to cc them you'll find they're actually around 62cc plus change. Not enough of a difference I felt like milling them, so I threw them on as-is. They absolutely blew the stock heads into the weeds, performance-wise, despite the slightly lower compression.
Note, I was using them on a 305 with factory flattop pistons, so I was starting with 9.5:1 compression to begin with. Probably low 9s once the stock Vortecs were bolted up top. The engine didn't care about the slight loss of compression. The Vortecs still made more power everywhere in the RPM range and didn't nose-over on the top end like the stock heads.
Note, I was using them on a 305 with factory flattop pistons, so I was starting with 9.5:1 compression to begin with. Probably low 9s once the stock Vortecs were bolted up top. The engine didn't care about the slight loss of compression. The Vortecs still made more power everywhere in the RPM range and didn't nose-over on the top end like the stock heads.
Everybody gets caught up on static and dynamic compression ratio, when in reality its cylinder pressure that you want and cylinder pressure is highly dependent on head flow, cam timing, intake and exhaust dynamics and ignition timing.
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