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87IrocTim
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PostPosted: Fri May 12, 2006 9:25 pm    Post subject: possible bad news Reply with quote

well i was told my heads were 2.02 intake and 1.6 exhaust. but i looked up my head casting numbers today, and they came out to be one of like the worst heads made. 1.74 intake and 1.5 exhaust. thats complete junk. even if bigger valves were put in, those heads would still not breathe for shit. i mean, the motor runs good and all, but my question is would i be able to tell if this head is really that shitty from how it runs? i mena i know it owul dbe holding back power, but would it hurt high end horsepower? my motor has been at and almost past 7000rpm, and didnt take long ot get there, would a head this crappy be able to do such a thing? the casting number is 3927185. and if i were to buy new heads, which would you prefer? i was looking at either the cast iron sportsman II's with 72cc chambers, 2.02/1.60 valves. or aluminum heads with 64cc chambers 2.02/1.6.
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10sec.et
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1969 Oldsmobile Cutlass

PostPosted: Fri May 12, 2006 10:37 pm    Post subject: Reply with quote

i was having problems with the factory heads on a 383 Chevy so i bolted on a set of sportsman II heads and they made a HELL of a lot more power. i would definitely suggest those.
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Aerosmith
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PostPosted: Fri May 12, 2006 11:25 pm    Post subject: Reply with quote

I have Dart Iron Eagles...64cc chambers, 215cc intake, 2.055/1.60 valves. I'm completely satisfied with them.
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jeep_406
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1972 Chevrolet Nova

PostPosted: Sat May 13, 2006 8:41 am    Post subject: Reply with quote

If you're happy with the performance, I'd drive it. Take it apart during the winter if you have to.
I run Sportsman II's on my 406 and am happy with them. They had extensive port work especially on the exhaust side. But if I was hunting for another set of heads I'd look seriously at an aluminum set. There are so many to choose from now.
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clay
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1972 Chevrolet Nova

PostPosted: Sat May 13, 2006 8:54 am    Post subject: Reply with quote

I agree with jeep_406, I also run the Sportsman II's, but I did some port work on them, especially on the exhaust side. Flow numbers aren't outstanding out of the box (especially the exhaust) and are very similiar to the Vortecs which are about $300 - 400 cheaper. Go to Chevy High Performance's web site and look for the cylinder head flow database. They tested a lot of heads a while back and it will definately help in the decision making process. Clay
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disturbthepeace1
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1965 Volkswagen Beetle

PostPosted: Sat May 13, 2006 12:46 pm    Post subject: Reply with quote

if your are going to consider spending the cash, I would highly rec the edelbrock performer rpms, i have used these along with the victor jr's and mde nothing but power with them... do your reserch and look at Chevy High performance.com head data base youll see that the AFR's flow some amazing numbers with smaller intake runners. perfect for a smaller motor like yours... by the way i suggest whatever head you choose get a 64cc chamber.. the 9:1 with a 74cc chamber isnt consider a real power freindly combo.....
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Paul P
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1971 Chevrolet Chevelle

PostPosted: Sat May 13, 2006 12:47 pm    Post subject: Reply with quote

My 406 has Dart II sportsman Aluminum heads with a lot of port work as well. They are the bottleneck to making more power though. The heads flow numbers support 522 HP by the numbers and the motor made 532HP on the Dyno.
I do have an upgrade planned though. I have some Seriously ported Dart 17 degree heads with the matching Wilson intake and Jesel shaft rollers. I have yet to install due to lack of cash to do the upgrade. They are capable of supporting well over 650+HP airflow wise so when it does happen it should be nasty... Twisted Evil

For the 305 I recently read an article in July CHP magazine titled torquey 283 page 14 that there are Sportsman S/R torquer 305 (PN 42650-1) which feature 58cc chambers, 171 inlet ports, and 1.94/1.50-inch valves. They come assembled with .560 lift springs.

There are also some Trick Flow 23 Degree 175cc heads for your motor on page 92 of the same magazine they are $1100.00 for the pair and probably make more power and have .600 lift springs installed.

These sound like good heads to use for your application. thumbsup

The big valve heads meant for 4 inch bore smallblocks won't clear the 305's small bore of 3.740 so don't waste the money on them they won't fit!!!!
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87IrocTim
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PostPosted: Sun May 14, 2006 10:03 am    Post subject: Reply with quote

i have heard a lot of good about the sportsman II heads, i did want aluminum heads so i could run a little higher compression but they are offly expensive. first of all im going to find out what type of pistons i have, whether they are flat-top or dished or whatever, so i can make a better decision on what combustion chamber size to get. im going to look up every head that all of you suggested, and write down some prices and specs, and ill get back to you soon. thanks for the help so far. Tim. Paul P im not sure if you knew but its a 350. Im not sure if you knew because you mentioned 305's a lot in your post.


oh yea and jeep 406, ill have the money for new heads in late june or early july, so i think im going to buy them, and hold on until late august to put them in, because its running damn good at the moment.

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87IrocTim
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PostPosted: Sun May 14, 2006 10:38 am    Post subject: Reply with quote

ok well i did the research, and so far i think im going with edelbrocks performer rpm's. they make one with 70cc chambers, so it will pretty much be a direct replacement, and it costs $979.99 for both so thats not half bad. so basically to install these, im going to need the bolt torque specs, already have a torque wrench, a new head gasket, i think im going to go a tad thinner to bring up the compression slightly, and intake manifold gaskets. is there anything else im going to need to put these in? obviously im going to reuse my rockers, and my pushrods are brand new. and is there anything i need to know about edelbrock rpm heads, like any porting needed or bad reputations or anything like that. thanks a lot so far. i was looking at Dart and Brodix heads, but a little too pricey for me.
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Paul P
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PostPosted: Sun May 14, 2006 11:25 am    Post subject: Reply with quote

Ooops! sorry I thought it was a 305 my mistake. Shocked
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af2
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1933 Willys Coupe

PostPosted: Sun May 14, 2006 11:30 am    Post subject: Reply with quote

Myself I would go with the Protopline/Proaction head in a 180 cc runner. The reason is the combustion chamber design and excellent flow at .500 lift. I am running the World Mototown heads just because of the chamber. Here is a good pic of the design.http://cgi.ebay.com/ebaymotors/235cc-pro-topline-iron-heads-chevy-sbc-350-383-406_W0QQcmdZViewItemQQcategoryZ33617QQitemZ8065136477QQrdZ1QQsspagenameZWDVW
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SMOKEmUP
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1979 Chevrolet Camaro

PostPosted: Sun May 14, 2006 12:09 pm    Post subject: Reply with quote

Since you're changing heads, now is a good time to adjust the compression ratio and dynamic compression ratio, DCR. Measure the deck height then select a head gasket which will give you a good quench height, try to target about 0.045". Try to set the DCR so it works out to about 8.0 : 1 for iron heads and 8.5:1 for aluminum heads. The DCR is dependant on your camshaft so you'll need to know the intake valve closing point ABDC of the cam.

For cylinder heads I would stay under 200cc intake port volume, anything bigger and you'll lose low end. Make sure the springs are setup to handle the lift of the cam you plan to run.

What cam are you running? Do you plan to change it?
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87IrocTim
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PostPosted: Sun May 14, 2006 1:56 pm    Post subject: Reply with quote

i am running comp cams high tech mechanicle. it has 250 intake duration, and 260 exhaust duration, with .532 intake lift and .555 exhaust lift. its still brand new so i dont plan on buying a new one. im jsut trying to find a new pair of heads that can breathe better, but be pretty much a direct replacement. the performer rpm heads have a 170cc intake runner and htey have a .575 max lift. which thickness head gasket do you recommend? i know i dont have domed pistons and i have 70cc chambers, so it has to be a rather low compression, around 8.0:1, i would like it to be 9.0 or 9.5:1, should i run a compression test and see hwat im running at? i want to up my compression, but i also dont want to mess with the motor too much.
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af2
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1933 Willys Coupe

PostPosted: Sun May 14, 2006 3:01 pm    Post subject: Reply with quote

I would run at the most a 64cc chamber and #1010 Felpro head gaskets. I really dislike the chamber in the Performer head. There are a lot of other heads that have the heart shape combustion chamber that is a proven design.
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SMOKEmUP
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PostPosted: Sun May 14, 2006 3:10 pm    Post subject: Reply with quote

What are the rest of the specs on the motor?
Bore, 4.0 ?
Stroke, 3.48 ?
Rod Length, 5.7?
Deck Height?
Piston Dome Vol.?

What is the intake valve closing point @ 0.006"? If you don't know what is the cam part #?

I agree with AF2. You can do much better than edelbrock heads.
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