Ok well then how about these heads?

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HotrodDaddy43
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Ok well then how about these heads?

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Smiliesafari
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Re: Ok well then how about these heads?

Post by Smiliesafari »

It depends on what you are trying to achieve. I don't see a big difference in these heads. Have you considered GM iron vortec heads?
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1Gary
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Re: Ok well then how about these heads?

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In a way I agree with Skip in what you want to achieve.Might be just me,but it seems everyone reaches out for the Vortec card to play.Some because of a compression increase,but you get that with at the end of the day,heads that don't match flow numbers very well with the aftermarket has.And Vortecs by the nature of what makes them Vortecs really can't be ported on the intake runners.It's the rough surface in the runners that make them work as Vortecs.The ideal intake runner size for 350/355 is 180cc.Not much of a trade off(you no matter what you do will always have some sort of a trade off)in the bottom end.Fact is your dealing with a very heavy vehicle that has the aerodynamics of pushing a sheet of plywood down the road.So for the street light to street light type of consideration you I suggest should build in a van as much bottom end as possible.And for yrs this site has suggested a rear end gear change(or in a AWD both ends with the same gear ratio)to bring the V6 4.3's up into the beginning of it's power curve.That even if later you swap in a V8 is useful.If you don't have posi to add it in at the same time is a real plus too. I am strongly suggesting a build plan starts at the rear end first and it's effect on choices for compression ratios,which impacts cam choices, which impacts which heads,which impacts power curve results in normally drive ranges for your van.My point is your spending the money and should see the results from that as much time behind the wheel as you can.


Because I don't know you that well,you might know what I am about to suggest you look at in the following links.If you do know this stuff,please don't be offended.

The static compressions ratio is the pure mechanics of what is the compression given a compression chamber size.It can be found in this link under engine compression."SCR"

http://www.csgnetwork.com/automotiveconverters.html

As you will see there are a number of formulas including a rear end gear ratio that tells you at what speed what the RPM would be that you might find useful.I suggest you bookmark it.

The dynamic compression ratio is what is the compression while both intake and exhaust is open bleeding off some of that compression because of the cam profile in it's overlap."DCR" Again you might want to bookmark this link because of many useful formulas.

http://www.wallaceracing.com/Calculators.htm


Now while I was figuring out the 383 build,what I found is the parts market really isn't geared for the "medium" performance street vehicle for today's gas.Well atleast in my case something that was intended for performance,regular gas and a cam for easy tuning of a EFI.So it took some finagling with piston choices,rod lengths,deck height,and head choices to get to a final build sheet for a good matched 9.3 compression ratio.Honestly before that because of the race engines in the past we have done and those not really taking into account the factors of a street vehicle I hadn't realized how lacking the parts market really is for a street car/daily driver.

I hope this helped,

Gary
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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1Gary
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Re: Ok well then how about these heads?

Post by 1Gary »

Here is 108 SBC builds.It is alittled dated,but does have some window shopping benefits:



http://www.ryanscarpage.50megs.com/combos1.html

If at all possible,I suggest you get a 96 and up block that is a roller hydro cam block.Buying that over a hydro conversion which it pretty expensive will save you money along having all the benefits a hydro roller has.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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Mr_Roboto
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Re: Ok well then how about these heads?

Post by Mr_Roboto »

How high are you looking to/are willing to spin this sucker up? That's a big question with looking at aftermarket heads. If you're not willing to spin it high enough for the cubes to use it there's no use getting big heads if anything they'll hurt you.

The Vortecs are decent, but honestly they require some work to the valve train stuff to bring em up to par. This includes time at the machine shop. The exhaust ports need some work too tbh. The other thing I'd look into is the Dart SHP heads. I mean, you've got other things besides flow to keep in mind like chamber design, aluminum vs. iron compression and weight. Overall I'd probably actually do something like this over the Vortecs. The other thing is do you have an intake already? If you're looking on the secondary market or have something already a non-Vortec intake is usually cheaper and easier to obtain. Even new you can have a premium for the intake that's significant, ~100 bucks seems typical. This is a hidden cost to the Vortecs in my opinion that a lot of people over look and it closes the price gap quickly IMO. The stocker EFI setup is supposedly good to ~400hp from what I've heard and the intake its self is actually well designed I just don't like the fuel system attached to it over all.
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1Gary
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Re: Ok well then how about these heads?

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We are finding the advertised cc runner size isn't as important as the cross section.So some companies cc rating really doesn't matter.What is more important is the brand of who's heads they are.RHS is one example who's design of the head does account for cross sections.Now I am not talking about engines operating in upper rpm ranges,but tailor design heads from the slightly over stock to race engines.You can tailor a torque curve to better apply to street driven vehicles,but don't really have much hp.It is one of the trade offs.The formula for all engines rule of thumb is .5 x c.i.= the size of a intake runner.Knowing that with my 383 build it should need a 195 cc intake runner.I am going to use a 180 cc intake runner to keep the velocity up for a lower bigger torque curve,but I know it will only have in the range of 350 to 375 hp.All these yrs we have been sold on hp and really to get the biggest bang for the buck you spent is torque and not hp.Take that and with the knowledge you built a stroker for it's torque ,you put on heads to use what is natural for a 383.Tailor built so to speak.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY

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HotrodDaddy43
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Re: Ok well then how about these heads?

Post by HotrodDaddy43 »

well now that I've found a job again. I've gone off the deep end and decided to put a great big turbo on something. Okay not great big but I have wanted to turbo something for a while now and this is it. So thanks for all the input I am going to start researching what I need to learn about doing this. so I will start another thread and ask a lot of questions there. lol
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1Gary
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Re: Ok well then how about these heads?

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Me and turbos not so much.But Mr_Roboto knows alot about them.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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Mr_Roboto
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Re: Ok well then how about these heads?

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1Gary wrote:We are finding the advertised cc runner size isn't as important as the cross section.So some companies cc rating really doesn't matter.What is more important is the brand of who's heads they are.RHS is one example who's design of the head does account for cross sections.Now I am not talking about engines operating in upper rpm ranges,but tailor design heads from the slightly over stock to race engines.You can tailor a torque curve to better apply to street driven vehicles,but don't really have much hp.It is one of the trade offs.The formula for all engines rule of thumb is .5 x c.i.= the size of a intake runner.Knowing that with my 383 build it should need a 195 cc intake runner.I am going to use a 180 cc intake runner to keep the velocity up for a lower bigger torque curve,but I know it will only have in the range of 350 to 375 hp.All these yrs we have been sold on hp and really to get the biggest bang for the buck you spent is torque and not hp.Take that and with the knowledge you built a stroker for it's torque ,you put on heads to use what is natural for a 383.Tailor built so to speak.
There's a ton more to head work that cross sections. I've been reading some of the theory that Dart is putting into their heads these days. They are using wet flow to determine more realistically how the heads should flow. Supposedly the new Pro1s flow a few cfm lower than the new ones and make more power. Cross section is a good raw indicator but the overall design is very, very important.
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Re: Ok well then how about these heads?

Post by 1Gary »

Mr_Roboto wrote:
1Gary wrote:We are finding the advertised cc runner size isn't as important as the cross section.So some companies cc rating really doesn't matter.What is more important is the brand of who's heads they are.RHS is one example who's design of the head does account for cross sections.Now I am not talking about engines operating in upper rpm ranges,but tailor design heads from the slightly over stock to race engines.You can tailor a torque curve to better apply to street driven vehicles,but don't really have much hp.It is one of the trade offs.The formula for all engines rule of thumb is .5 x c.i.= the size of a intake runner.Knowing that with my 383 build it should need a 195 cc intake runner.I am going to use a 180 cc intake runner to keep the velocity up for a lower bigger torque curve,but I know it will only have in the range of 350 to 375 hp.All these yrs we have been sold on hp and really to get the biggest bang for the buck you spent is torque and not hp.Take that and with the knowledge you built a stroker for it's torque ,you put on heads to use what is natural for a 383.Tailor built so to speak.
There's a ton more to head work that cross sections. I've been reading some of the theory that Dart is putting into their heads these days. They are using wet flow to determine more realistically how the heads should flow. Supposedly the new Pro1s flow a few cfm lower than the new ones and make more power. Cross section is a good raw indicator but the overall design is very, very important.

Yeah I read about the wet flow tests.It makes sense.My point is two fold.The days of port matching with a die grinder and gaskets is rapidly fading away.Much more have been found in the tech R&D and the CNC porting done right.The other thing is you can't really take intake runner size as it is advertized.There is a ton more than that as there is a ton more into CNC porting..................Some of the off shore companies have a hard enough time just producing reliable heads let alone CNC port them.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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Re: Ok well then how about these heads?

Post by Mr_Roboto »

1Gary wrote:
Mr_Roboto wrote:
1Gary wrote:We are finding the advertised cc runner size isn't as important as the cross section.So some companies cc rating really doesn't matter.What is more important is the brand of who's heads they are.RHS is one example who's design of the head does account for cross sections.Now I am not talking about engines operating in upper rpm ranges,but tailor design heads from the slightly over stock to race engines.You can tailor a torque curve to better apply to street driven vehicles,but don't really have much hp.It is one of the trade offs.The formula for all engines rule of thumb is .5 x c.i.= the size of a intake runner.Knowing that with my 383 build it should need a 195 cc intake runner.I am going to use a 180 cc intake runner to keep the velocity up for a lower bigger torque curve,but I know it will only have in the range of 350 to 375 hp.All these yrs we have been sold on hp and really to get the biggest bang for the buck you spent is torque and not hp.Take that and with the knowledge you built a stroker for it's torque ,you put on heads to use what is natural for a 383.Tailor built so to speak.
There's a ton more to head work that cross sections. I've been reading some of the theory that Dart is putting into their heads these days. They are using wet flow to determine more realistically how the heads should flow. Supposedly the new Pro1s flow a few cfm lower than the new ones and make more power. Cross section is a good raw indicator but the overall design is very, very important.

Yeah I read about the wet flow tests.It makes sense.My point is two fold.The days of port matching with a die grinder and gaskets is rapidly fading away.Much more have been found in the tech R&D and the CNC porting done right.The other thing is you can't really take intake runner size as it is advertized.There is a ton more than that as there is a ton more into CNC porting..................Some of the off shore companies have a hard enough time just producing reliable heads let alone CNC port them.
Pretty much all of the raw Procomps are actually shipped into the US as bare castings. The final work (porting, valve job and other machining) are only going to be as good as the company doing them. By the time you get into all of the porting to make a Procomp flow well you're getting bucks ahead to buy good heads. If you're just looking to shave a few lbs, probably get some power over a set of unported double humps and get a set of heads that aren't cracked (for vintage SBC heads this can be a trial) the Procomps can fit the bill. Overall I'd rather eat ramen for a month or two extra and get some of the Dart, Edelbrock or Brodix heads though if you aren't willing and able to port on them yourself. If you can, then these heads would be a decent solution potentially.

I'll disagree on hand porting being dead. A machine can only do so many angles, besides this the program is only as good as the person programming the machine makes it. Usually the higher end "CNC jobs" are actaully finished up by hand porting.

Another thing worth nothing is that the areas that benefit most from porting can be done fairly easily by an experienced porter. This includes the bowl and the valve job (probably the most over looked part of porting.) I had a buddy of mine that took a set of heads to a pro porter, he spent about 2 hours in the bowls on a set of 8445 Buick V6 irons. They made within 5% of what a set of GN1s did which are CNC ported. He spent $200 on that work versus $1200 on the GN1s. For a street car would the 5% really be worth it versus $1000 that could be spent on a billet retro roller cam or other components? Yeah full out porting is great for the race guy looking for a couple extra HP at very little concern for the price but the average joe isn't going to notice that much in all probability.
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1Gary
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Re: Ok well then how about these heads?

Post by 1Gary »

Alex-I disagree with you about hand porting mainly because duplication is a issue that all the major head companies have said was the original reason behind going to CNC 5 position programing.Well that and labor costs as you know profit is going to always be behind the motive.The programing that is used is a simulation for flow not trial and error.RHS being the for runner.

I agree with you to buy known brand names for the product they make in the first place and for the dollars they have to spend in R & D.Pro-Comp had/has some issues that I really don't want to get into details in this thread.All I am going to say is "A deal really isn't".Like anything else.............ya get what ya paid for.
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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