nealro

Easy there tiger - did someone from Procomp **** you off or what? Not to get too off-topic for the poor guy just wanting an answer to his question but... From your comments, I assume you've not had good luck with Procomp. I tend to agree with your statement that the cheap stuff from China is junk - I however have yet to see proof that these heads are cast in China - I'm not saying they aren't, just saying I've never seen proof, just hearsay on forums. I have e-mailed Procomp about this and am awaiting a response. I also did not say they were any better than AFR or Dart or anybody else. I was simply sharing my opinions and experience. For the record, Procomp electronics is/was based out of Australia when I bought my heads and now their website says California. So let's just do a little expirement, I'll try em out, run the **** out of them and see how they do, if they crap out I'll let you guys know and then I'll go out and get a set of AFRs .

my77stang

^ there are a handfull of guys in the 5.0 section who have bought these heads from various websites or ebay sellers, and have had problems in the long run with them. so there's that.....

being someone who is "intimate" with cylinder heads seeing as how i spent 5 years doing cylinder heads in a machine shop i have seen what works and what doesnt.

there are OEM aluminum heads with inherent flaws, which lead to catastrophic failures. for example, 1.9 ford escort heads LOVE to drop seats, and 3.0 V6 mitz heads like to drop guides (mitz later added clips to keep the guides from falling down) 2.8/3.1 chevy V6's also drop guides.

why? its from one of two things - impromper machining so you end up with press fits that arent tight enough, or poor metallurgy where the heat "softens" the aluminum up enough for the seats and guides to move.

then we run into cracking which some castings are inherently prone to happen based on the design and/or molds, again.... from OEM manufacturers.

knowing this, i would never be able to convince myself that some off-branded chinese company could make something that will hold up to the rigors demanded by high performance applications.

just food for thought dude...... food for thought

Starfury

GT40P heads, while good for performance, are NOT good for early Mustangs. They require special headers to clear the altered-angle spark plugs, and to my knowledge there are only a couple of manufacturers who make them, and they're all really high end ($500+).

Standard GT40's are good, but I don't see the sense into putting money into rebuilding a set of factory heads (which will probably run ~$700 once all's said and done) when you can just pick up some solid aftermarket heads for $300 more. World Products' Windsor Jr. heads are very good out of the box, durable (cast iron), and relatively cheap ($1k).

my77stang

the world windsor jr's flow crappy when compared to all the newer aftermarket though. if you want cast iron look at RHS heads, they make cast iron and aluminum

Starfury

You're also talking about quite a bit more money for the RHS heads. Windsor heads are cheap, and flow better out of the box than even ported stock heads

67mustang302

As far as Procomp heads...they don't get the best of praise from those who use them. The alloying in them isn't that great. And no matter how good the head looks you'll never be able to tell unless you're a Borg from Star Trek with a molecular imaging subspace scanner for a left eye that you can use to see the molecular grain structure and alloy composition of the metal. It's what the metal is like at a microscopic level that matters. Bad alloy mixtures and dispersment combined with poor grain structure = metal that fatigues and fails.

As far as port and valve sizes....if you think that 165cc intake runners or 1.90 intakevalves are too small for top end power, then you don't understand how an engine works. I'm running out of the box AFR 165's on mine, they have 1.90 intake valves and 165cc runners, and my 302 will pull WELL past 6,000rpm witha hydraulic roller cam without slowing down one bit, and that's with a modest sized cam and a 570cfm carb on a dual plane intake. 180+cc intake runners on a 289/302 are for something that you want best top end power with little concern for overall torque. Stock AFR 165's are capable of supporting well in excess of 400hp naturally aspirated. Smaller ports keep intake velocity up and make more power in a streetable rpm range(up to 6k+ rpm). Larger ports need more rpm to get the same velocity

andrewmp6

go nuts and buy these http://www.araoengineering.com/Ford/frdsmb.htm

nealro

Put your safety glasses on everyone, we've started a wee-ing contest over who knows more! I agree with you, velocity over volume, but it does depend on the head as to whether say a 165cc runner will have better velocity than 180cc or 215cc will have better velocity than say a 230cc. I'll add a link below in this post, I'll bet you can spot at least a few configurations where the larger runner outflows the smaller, not always but it happens. For the record, your AFR 165's do outflow AFR 185's. Now in real life, not on a flowbench, there are a lot of more aspects to consider, it may not always work out that the larger runner beats the smaller and vice-versa, as already mentioned valve size and bore diameter are going to come into play as well as cam lift and duration. Ah, we could argue much further on the subject but this chap would never get an answer to his question.

Well rumblestang, as you can see there's lots of options and lots of opinions on the matter, so you may have to just do a bunch of homework to determine what will fit your needs best. You'll need to take into account how you want to drive the thing, ie are you gonna bracket race on week-ends or just want a decent street rod or just a little better performance from your daily driver. You'll also need to take into account the specs of your cam as well as what intake and carb you'll be running. And of course the big one, $. There's a lot of factors in determining a package that works well together.

I came across this website that is a tabled collection of flow ratings on tons of different heads with different valve sizes, port volumes and combustion chamber sizes. Check out the Windsor section, learn what the numbers mean and make a decision based on that info as well as tips you hopefully gathered throughout our bickering like, there is such thing as too big (valves and port volume) and velocity over volume. Also while you're looking at the link, keep in mind there are lots of factors involved in choosing a good head, don't base them solely on the benchflow numbers.

nealro

I don't want to start any additional discussion about ProComp heads but wanted to pass on the response I got from ProComp after e-mailing some questions. The following is an unedited copy and paste of their response:

I understand were you are coming from, but the truth is that any product that you speak about in forums on the internet will have both positive and negative responses.However what I can tell you about the head is that It is the former ProTopLine head(don't know if you are familiar with it). The castings are actually made in Australia. We did try to have them manufactured elsewhere before but we did not like the quality of the product nor the response we were getting from our customers or our vendors,(That is probably were some of the bad feedback came from).You can go on Direct Motion.com for specs on the head and flow numbers. Just click on the upper right hand corner on the "DM Motorsports"logo ,you will see all the numbers.Please let me know if there is anything else we can do for you.Thanks
Jay Verduzco
Procomp Electronics
605 S. Milliken Ave. Unit A
Ontario, Ca. 91761
Tel: 909-605-1123
Fax: 909-974-1155
Web: www.procompelectronics.com

my77stang

i coulda swore protopline's castings turned into RHS heads[&:]