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Old 06-18-2010, 10:34 AM
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305 Vortec heads.

Does anyone know how much they flow? How alike they are to their 350 counter parts? I have found very few reviews. Mostly bad.

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Last edited by ThirdDegree; 06-18-2010 at 11:50 AM.
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Old 06-18-2010, 12:08 PM
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Heads are supposed to be good

They are great for up to 400 hp but have limits. there really efficiant and make lots of power with low lifts and work flow best with flat or dished pistons in stock form..comp make a tool to machine the valve seat to fit regular springs and presto a good street head. most real high power stuff ive seen has been with roller tappet setups in the 270 @50 duration rangs lift doesnt need to be high to make power.
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Old 06-18-2010, 12:13 PM
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I saw engine quest has a bare head listing for 380 a head. Do you know where to find these complete and new?
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Old 06-18-2010, 03:19 PM
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Quote:
Originally Posted by ThirdDegree
Does anyone know how much they flow? How alike they are to their 350 counter parts? I have found very few reviews. Mostly bad.
Where have you been? The magazines and books are full of Vortec reviews though we're 15 years past their introduction so they don't capture headlines like they used to.

In test after test compared to other production Chevy heads they deliver a 20 to 60 horse improvement by just bolting them on. 20 horses against older small chamber heads like the 462 or L98 when ported and 40 horses against these heads unported. 40 horses against large chamber heads like the 441 or 882 ported and a solid 60 against these heads unported. Plus the Vortec doesn't give up much bottom end torque, not enough to be felt. There are heads like the GMPP Fastburn which is essentially an LT4 head made for conventional coolant flow which will out flow the Vortec and certainly many aftermarket heads that will but they all give up a lot of bottom end to do it and cost a lot more. Then again the GM Vortec does require a Vortec specific intake and whether you get one from GM or off the aftermarket they are a bit pricey.

With Vortec heads and a cam like the Comp 262 to 268 with a 650 to 750 Holley and full length headers, the engine will make around 400 horses with an otherwise production bottom end. With changes to the piston to a D dish to improve the squish/quench characteristics and get the compression up around 9.25:1; it is possible to move that number toward 425 from 350 inches and have a very streetable motor that will take an automatic without having to up the converter stall.

Bogie
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Old 06-18-2010, 04:03 PM
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Wow. I had to copy and save that^^. Good future reference.
Quote:
a cam like the Comp 262 to 268..
Is this^^ roller or flat tappet?
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Old 06-18-2010, 04:50 PM
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Im talking 305 vortecs vs 350 vortecs, not pre vortec vs vortec, fastburn etc. I have been doing Fords, like what it says in my intro post. The 305 is flat tappet.
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Old 06-18-2010, 05:40 PM
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Quote:
Originally Posted by ThirdDegree
Im talking 305 vortecs vs 350 vortecs, not pre vortec vs vortec, fastburn etc. I have been doing Fords, like what it says in my intro post. The 305 is flat tappet.
305 heads while called Vortecs are not in that they do not include any of the features of the L31 Vortec found on the 350. The 305 vortec is simply a rehash of the 305 heads, some are slightly better than others but none offer the advantages of the L31 Vortec. Something GM's advertising department knows nothing about.

Back in the 1970s and 80s it was popular to use the 305 head as an inexpensive and quick way to get the compression up on a 350. For a 350 this took porting to 350 port dimensions and installing 350 size valves, an activity as like to find coolant as result in usable ports. Regardless of the ports achieved, unfortunately the 305 combustion chamber is inefficient at best. It has the spark plug in a distant location from the center of the cylinder bore as with the large smog chamber 350 heads of that era resulting in a long burn time that requires too much advance which causes the engine to be detonation sensitive and fuel hungry . While most rodders are carried away with port and valve sizes as the path to power, the subtle shapes of the combustion chamber are equally as important if not more-so toward power development. This is where the really important changes in the L31 head occur. The combustion chamber of the L31 head returns the lost knowledge of Sir Harry Ricardo to engine design. Over at Ford it's the GT40 head and at Chrysler the Magnum LA or Ram head. All of these heads push the spark-plug as far toward the center of the chamber as the valve location permits, introduce the so called heart or liver shape which provides dual side squish and quench for fine fuel and air mixing (squish) and an area of heat sink (quench) which builds detonation resistance. A beak is projected from the squish/quench deck between the valves to isolate and redirect intake flow from going out the exhaust valve during cam overlap. All this is long known technology from before WW-2. These configurations can be found used on the 1953-55 Lincoln Y block and the 1954-55 Ford Y block, in a somewhat simplified form on the 1955 to 1970 Chevy small block, as well as others. But gradually these features were removed by the finance cost cutters at the factory which had the effect of reduced engine efficiency and detonation resistance. The factory's figured that the cost they saved of a few cents per head which reduced your performance and increased your operating cost due to higher fuel burn rates, and the increased emissions into the environment could just be transfered to the end user. This worked into the mid 1980's when increasing government regulation on emissions and fuel mileage finally forced them back to original and more efficient design principles.

The incorporation of electronic fuel injection and Honda's stratified charge combustion chamber being the final irony as both are American inventions rejected by American manufacturers back in the 1950s. EFI was developed by Bendix using the then new transistor technology and offered as an option by Chrysler in 1956 and 57 but people were more interested in putting their extra money into air conditioning. The hugest irony is that the stratified charge technology used by Honda was developed by Texaco under a government contract with NACA (the predecessor of NASA) to develop a method to increase the range of bomber aircraft so that Germany and Japan could be reached by bombers from the continental United States should England and Hawaii fall into enemy hands.

Anyway 305 heads on 350's is old hat. The work and cost it takes to make them competitive against a comparably equipped L31 Vortec headed engine isn't worth the outcome. The money is better spent on L31 heads even for, and they will fit, a 305, just getting the valves into the cylinder bore, but just is more than good enough in this case.

Bogie
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Old 06-18-2010, 08:10 PM
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Liver shaped? That gave me a much-needed chuckle, thanks for that.

Anyway, you might be thinking of a different organ- possibly kidney??
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Old 06-18-2010, 09:09 PM
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Quote:
Originally Posted by ThirdDegree
Does anyone know how much they flow? How alike they are to their 350 counter parts? I have found very few reviews. Mostly bad.
Take a look at POST #478.

This entire thread is a good one, lots of Vortec info, mainly on the L31 5.7 heads, not the L30 5.0L heads, but good nonetheless.
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Old 06-18-2010, 09:21 PM
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Quote:
Originally Posted by cobalt327
Take a look at POST #478.

This entire thread is a good one, lots of Vortec info, mainly on the L31 5.7 heads, not the L30 5.0L heads, but good nonetheless.
Very good link. I've never anything bad to say about the 059's (probably because my DD is powered by an L30). It was definitely a decent powerplant for it's time and place. For anyone who's interested in some flow numbers, these are from the Stan Weiss flow chart:

Vortec L30 "059" casting:

0000 Int Ex
.100 68 47
.200 128 103
.300 179 138
.400 205 152
.500 221 163
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Old 06-19-2010, 07:02 AM
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Yes see, those flow numbers arent bad for a 305 head. But the real problem when using vortec with older EFI systems is in the base. It costs $450 bucks just to complete the combination. It all adds up to too much cash for the performance you get. I would be better off with some worked s/r torquers from world or maybe even the box stock TFS 175cc 23* head. Keep in mind I am simply trying a head and cam package on a LB9 305 for better performance. I choose the vortec head because we all know it flows better at lower lifts, which is where TPI likes to make power and TQ.
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Old 06-19-2010, 01:24 PM
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Reworked S/R Torquers?! You still need the baseplate and those heads will cost just as much as vortecs.

You gotta pay to play. How much you want to play? Why would you even bother with a 305 TPI? You could probably get a whole 350 TPI for a couple of hundred. What are you looking for, torque or hp? TPI is all about torque.
If you must stick with a 305 then....Stock vortecs will handle a cam like a Comp XE 256. Want more cam? Then get the valve guide boss cutters that will allow more lift. Pick a pair of vortecs up at the local yard for $200, get your vortec TPI base, and your cam and lifters for $150 and you will have gained 40 horses and torque down low for $800 (or less if you shop smartly, scoggin dickey has the price for baseplate at $399, now you're at $750). Cheap for the gains you make.
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Old 06-19-2010, 02:24 PM
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Quote:
Originally Posted by cool rockin daddy
Reworked S/R Torquers?! You still need the baseplate and those heads will cost just as much as vortecs.

You gotta pay to play. How much you want to play? Why would you even bother with a 305 TPI? You could probably get a whole 350 TPI for a couple of hundred. What are you looking for, torque or hp? TPI is all about torque.
If you must stick with a 305 then....Stock vortecs will handle a cam like a Comp XE 256. Want more cam? Then get the valve guide boss cutters that will allow more lift. Pick a pair of vortecs up at the local yard for $200, get your vortec TPI base, and your cam and lifters for $150 and you will have gained 40 horses and torque down low for $800 (or less if you shop smartly, scoggin dickey has the price for baseplate at $399, now you're at $750). Cheap for the gains you make.
Local junk yards have NO vortecs. E-bay is the next place, but thats about $400. I can get a set, worked for $700.00 with beehives, guide plates, machined for .600 lift, ls1 style valves.. NEW! I was told NOT to cut them down to 58cc chamber, because it would alter the chambers too much. IS THIS TRUE? I know about paying to play. I play for a living. Just wanted to know if anyone had some cheaper alternatives. thanks.
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Old 06-19-2010, 02:48 PM
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Consider RHS vortec, better casting and more flow compared to production.
These heads new for ~$850 a pair assembled.

http://www.flatlanderracing.com/rhs-...rotorkerv.html
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Old 06-19-2010, 04:13 PM
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What about milling the head .036" to get the chamber I want?? If milling about .006cc off the surface ='s -1cc... A local machinist told me that that would not be a good idea. Honestly he didnt sound like much of a hot rodder. I can mill .024" thousands minimal for a 9:1 compression.
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