will a set of heads really change performance

[71Seth]

I have a sb400 in my 71 c-10 which has been pepped up a bit with .040 over with speed pro flat tops, comp 292H mag. edelbrock rpm performer intake, 750 holley duel feed, accle super coil we put a set of valve springs on but dont remember what they were. But it still has stock heads. I feel like this engine has great potentale right now but the poor flowing heads are killing it. What is a good set of heads that will flow good and give a performance increase w/o completly digging out my pockets. I like the look of aluminm a lot. better to buy complete or bear heads? Should i just look for some double humps? what sizxe cc should i get.
thanks seth

[71Seth]

whoops..............suppost to be on engine board but what the he!!

[Project1970]

My guess is yes, your heads certainly aren't helping things. I wouldn't go out looking for camel humps though; those plus work just about equal a lot of aftermarket heads out of the box in flow rates, but for a lot more money...and I wouldn't go Vortecs with that much cam, they're good heads on a milder engine but it sounds like you're going for more.

cc-wise, it just depends on what compression you want to run.

[71Seth]

whats pushing the limits of compression on pumped gas??

[Project1970]

I would try and keep it at 10.0:1 or close to that range if you don't mind running premium. You could probably go as high as 10.5:1 or maybe higher with aluminum heads; I know a lot of cars from the factory have 11.0:1 these days, but they also have knock sensors.

[71Seth]

thanks man
who else?

[bigjimzlll]

OK..i'll give it a shot...Dart iron eagles..pro-topline...world products..those are good iron heads..all around 800.00..complete...I like the idea of buying them bare and having a machine shop put them together..better QC.. for aluminum heads..AFR 190s are the best..Trick flow and canfields are next and the edelbrock rpms..the AFRs ae 1200..canfields and trickflows around 1000.00 and edes are around 900.00 With 76 cc heads the cr is 9.47-1 with 67cc its 10.43 10.43-1 is good with either aluminum or iron heads, with that big cam
Jim

[Eddie H.]

Most of the stock 400 small block heads were 76cc open chamber low compression "smog heads". They leave a lot to be desired in a performance engine.
There are many good performance heads out there, it just depends on how many "cubic dollars" you want to spend.
Personally I think the AFR heads are the best for building power. They're a bit pricey at around $1500 a set for assembled heads, but probably worth at least 50 hp or so on your engine combo.
The Edlebrocks are around $1100 and are pretty good heads also.
There are several cast iron performance heads available , but I don't have any experience with any of them, except the 202 double hump factory heads.
In any case, I would go with assembled heads and be sure to drill them for steam holes. With flat top pistons, I wouldn't use any smaller than 67 cc chambers. this should keep compression around 9.5- 10:5 ( depending on deck height and head gasket thickness)

[mikep]

I am of the opinion that there is no possible way that you can beat the flow numbers or the price of the pro topline heads. The 200 cc models are a modified vortec design with a greatly improved exhaust port and will outflow anything within $600 of their price range and not just at higher lifts either . Its all across the lift range. They are available in 55, 64 and 72 cc chamberings They retail for around $750 fully assembled or you can get the aluminum ones in kit form to be assembled by your machineshop for less than $800. You cannot beat that! There are so many options to the pro toplines it is hard to see why you would buy anything else. I'll be buying a set in the next month ! As soon as the damned board approves my bonus!

[DanoDMano]

Hey MikeP, I hope Seattles Best dont screw you out of that bonus!!

Thanks again for the Intake and Carb, it is gonna be nice!!

[casey]

Mikep, it's always a pleasure reading your posts, you sure seen to know your stuff, thanks for sharing.When I build my 383 I know who's brain I'm going to pick

[crazy longhorn]

a link to flow # http://www.airflowresearch.com/ go to articles, & look at flow to go, & flow to go part5. From what i see, AFR is top dog,& the Canfeilds are about next in line. a couple thing to look at on heads are balance in flow In vs Ex, & take a look at the .400 lift point as a quick compairison. The low lift # are also important for that good throttle responce. Personally the iron heads didnt impress me too much, & if you compair the .400 point , & the low lift # on the edelbrock 200 E tecs vs the iron head below them ....you will see what i am talking about. Im running on the street, so what i look for is good low lift #, good # @ .400 lift(that valve will spend more time @ the .400 point on opening & closing, than it will spend @ .500 lift), & also good balance in flow......crazyL

[mikep]

No doubt the AFR's and the canfields are excellent heads ! For the money though the Pro Action aluminum 180 cc intake port heads flow within 2% at .500" of the AFR's 190 cc and match the AFR's to within 1% of their flow numbers all the way down the line . The 220 cc aluminum pro actions flat blow the AFR's out of the water all the way down the line. Thats all for at the very least $400 less than the AFR's offer. I notice that the pro action heads are conspicuously absent from the AFR flow comparisons . Perhaps they only decided to include American made heads . Pro Actions are cast in Argentina and finish machined in the US ( Dont let their ads fool you. "Down under" does not always mean Australia ) .


I'm sorry . I think the original question was will heads really make a difference. The answer is yes . With a matching cam , intake and carburetor you could quite easily pick up a hundred to hundred and fifty horsepower . You also have to look at your converter if you are running an automatic and your gearing and size them to match your engine combination. That 400 CID motor of yours can hit 500 HP without struggling too much but you have to make sure that the rest of the truck is equipped to take advantage of the horspeower in the range where the engine will be producing it. The other question is what are you going to do with 500 horsepower. Thats a lot of power to be dragging around all the time. Sucks a lot of gas you know even sitting at idle or driving the kids to little league.

[crazy longhorn]

the Pro action Iron lightings are listed in Flow to go part5.....in a 220, & a 235 cc runner. The low lift # dont look good, but the y do pick up after .500-.600 lift. I didnt see the 200 cc versions for compairison tho.....

[mikep]

http://proshaver.com/ProCatalog.pdf

heres the catalog with the pro action flow numbers. check the 180 through 220 cc aluminum head numbers. for the pricing they are pretty impressive compared to the AFR's. Of course the low lift flow numbers will suffer with the larger ports. 235 cc ports are friggin huge and are not a fair comparison to the 190 AFR's. They do go up to 242cc for people who just cant get enough. I used to run a 351 cleveland with 4V closed chamber heads. You could stuff a Big Mac in those ports. Soggier than hell on the low end but over 4000 rpm it was a different story !

[crazy longhorn]

Yes, the larger ports will be soggy in the lower range on rpms. Thats just a given that we understand! as far a flow numbers in compairison , you might look at the diff in flow numbers from one site to another on the same sized heads. I looked at flow # on the iron lightnings on the pro topline site & compaired them to the Same heads tested by CHP on the AFR site (a 220 runner, & a 235 runner), & the numbers were way off......if they do flow as good as Pro topline claims they are damn good heads no doubt! To me it looked like the numbers might be "inflated".....might be worth a look see........crazyL

[bigjimzlll]

The pro-toplines look pretty good..I do believe they are inflated though..here are some actual flow numbers by actual people http://www.chevytalk.org/threads/sho...5&o=31&fpart=1

[crazy longhorn]

Thanks for that link Bigjim. Those numbers are more inline with what I was seeing from CHP testing. The flow looks good @ .500 & .600, but the lower # dont compair with AFR or Canfeild. The guys on the Olds board talk about the edel olds heads not flowing as stated also. sometimes, i think that independant testing keeps the manufacturer a little more "honest"......crazyL

[Reumster]

My Trick Flows made a big difference, from 194 camel humps I had

[71Seth]

thanks guys. got alot more detailed info than i had guessed i would on this. I am tring to build a bad ass street/strip engine here that will just put around town looking for prey mostly. Came into this knowing gas mileage would suck. Like i said before power feels good but could be more. I know a ass load of it is going out that 3.08 gear that came in the truck. I am looking now for a set of 3.73 posi and would like to get a set of tubs and huge meats. This is NOT a daily driver. Tranny is said to have a apx2200 stall is this too low? I am on a buget right now, looking for performance without going broke. I will spend $ To get a good product, but i'm not going out to race at the track for top dollar every wknd. Ya know. I'm new to the performance seen, need help making good decisions. All the guys around here drive or race f*#ds, so i cant look to them. What size runner do you recomend for my app. Can i do any good for around 1000 or less for a set? sorry, i'm a newbee just looking for some simple help. thanks yall
seth