Thread: which head??

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Talk with the tech staff at AFR and Brodix. See what they have to say and what they recommend. Like I said previously, and I can't say it enough times, "Do your homework!" You cannot make an informed choice without it. Have you called any turbocharger manufacturers to see what they recommend? Do that, too.

it appears that afr dont have a 72cc head... only a 74cc head.. that would lower my compression lower then 8:1 which IMO only gets better for forced induction.. ill all them

Dave

I agree with rumrumm. you should check out the AFR heads. They have some of the best flowing heads in the business. usually the smaller the port size the faster the velocity of the incoming air. You might get more air with the bigger ports but it wont be coming in as fast. sooooo what does this mean? A smaller amount of air but it will be coming into the engine faster. Usually you will get more flow until you get into the 4500 plus rpm range then the big port heads will really shine. It is knid of hard to explain without going in engineering terms. Just a couple questions. What stall speed will your converter flash at? What rpm will you be launching at? If you have not thought about it, you should call ATI and tell them what you will be running, they can build you a converter to match your application. Hope this gives you something to think about.

As I say, I'm no judge when it comes to engine building. But I have learnt one thing: Do it right now or do it again soon. It always pays to get info first. I didn't say the Dart heads are bad. Dart is certainly one of the best firms yround for aftermarket heads. But I was just trying to say that maybe for a twin turbo 350 those Dart heads might not be best choice. Almost every firm has heads in the 72cc region. But you might consider getting 76cc heads with a better chamber shape and have them machined down to get 73cc or so.
With a turbo you'll be seeing higher cylinder pressures so you wouldn't want heads that are known to be crack-prone. There are some castings that are quite heavy, but have thick castings and they won't brake. I think aluminum isn't a good choice, it isn't as strong as iron and might not survive the higher burning temperatures without warping soon. But that depends on how much boost you want to run later on. And on whether you want to use an intercooler and which one...
You see what I mean? Your first step has to be finding out what you want to do with the engine, what setup your planning for and whether you want a full blown racer or a daily driver which sees the strip now and then. Sketch out possible engine combos on a piece of paper and note what specialities you have to look out for.
You see? There's more to successful engine building than a set of good heads when everything else is already fixed. If your starting from scratch on this engine (except maybe for the short block), then do it right and find out FIRST what goal you want to achieve. Then find out what numbers you're aiming at (like 8:1 CR, 350 ci, 180cc intake runners with good bias...). Then see what parts that fit in this project you can get hold of. Then go and build the engine, drive that car into the 11s and have a lot of fun with it for years to come.
Or you buy everything YOU want. Then assemble the engine. Then find out it only puts out 300 HP. Then fiddle around, idle is crappy and power is low, engine doesn't turn higher than 5000 RPM and you loose every race
I hope you get what I'm trying to say. Make a sketch of the complete setup you want (this will prove more difficult than you think). Then make a list of brands to chose from. Then make a list of parts within those brands... Don't forget the small things like valve springs, retainers, rods (6 inch or 5,75 inch?)...
I can't give you any direct advice on your heads though, because I've never built anything not normally aspirated.
Hope I could help,
Max

I called AFR and Jason was a big help.. I told him what I felt I wanted to do with the engine..

mainly weekend warrior streetable with the ability to hit the track and have fun and get soem good pull up to about 6500rpm then shifting

he recomended the 195cc heads with 74cc chamber, says they will be there if I end up boring the block bigger they will flow great with the twin turbos, and not be to much in order to not run a crazy cam ..

he also recomended I upgraded the valves and springs with a upgrade package to suit the forced induction properly..

1500.00 for the set.. more then the darts but atleas tthis guy seemed alot more knowledgable and gave me the truth behind what I have been told by the local shops here..

Dave

ok I have done this with AFR and dart.. ill call brodix later

Dave

I am partial to AFR because they worked great for me and lived up to all expectations. My 383 (which has their 190 heads) with a relatively mild CC Magnum 280 hydraulic cam made 450 hp and 468 ft. lbs. of torque on the dyno, and it is so streetable my wife could drive it (if she wanted and if I let her). LOL! I have no problems with Brodix, Canfield or Dart. They have great parts, too. I chose AFR because they have the best flow numbers and a lot of guys on another Chevy website think very highly of them.

thx for you opinion I will keep collecting info from others as well

Dave

ok well after some conversations with brodix and some other place.. cant emember off hand.. I think AFR will be the best choice..

so there 195cc @ 74cc head will be what I will go for and I will get the upgraded spring/valve package with it..

I just ordered pistons today so once they arrive a few more things the the block gets worked, balanced, and assemebled then to heads

Dave

If you order AFR heads, buy them direct from AFR. That way you can be sure to get what you talked about. Keep in mind that they make up a set heads on a per order basis, and they do not have any pre-assembled sets on hand. That is why it will take about five weeks before you get them.

yeah they are actually 13 weeks behind right now.. I will buy direct but not yet..