How much H.P. from home ported 351w heads..........

I am building a .030 windsor and I am wondering how much power you guys get with a stock stroke hyd cammed engine with a set of mildly ported windsor heads, compared to say AFR out of the box. I am thinking of an air gap intake and a hyd. cam around .500-.550 lift and 285-295 advetised dur. at about 108 to 110 sep. I cant afford alloy heads so I must stick with iron windsor. I have a set of 69's and a set of 76's that I could use........Bob

you want..

http://www.jason.fletcher.net/tech/f...a/castiron.htm


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Wow, a lot of information.

Two things seem clear: you can buy better out of the box from World Products, etc than you can port yourself... an order of magnitude sufficient to put the idea to rest if you are doing anything but an RV engine or a resto. Getting a set fresh out of the box is probably the most economic way to get a 302 up in power.

The other: don't just look at .600" numbers -- look at the entire range (esp. if you top out in the .500's for lift!). The true determinant of a good responsive head is the low lift flow, the area 'under the curve'.

Valves only spend an instant at peak lift; the bulk of the filling comes at the low and mid ranges of the lift (which it will see twice, functionally) when the downstroke on intake is creating the biggest delta, or pull against the port.

Peak lift coincides with the lowest delta, usually when the piston is already down the hole or darn close to it.

Good Luck!

Use the 69 heads if money will allow, install exhaust seats, 1.60 ex. valves, 1.94 int. valves and port your brains out.

If you got no money at all, or just enough to freshen it up use the 76 heads, just port them and have a three angle valve job done, they already have hardened seats. Work on the exhaust side of the head first and if you feel up to it do the intake side, it does take a while if you are as particular as I am. It will breathe a lot better than not doing any port work at all. A few days on a grinder will be the cheapest horsepower you can find and the most gratifying.

But if you got a bunch of money kicking around or can get a set used by all means get them.

Link to my porting pics. http://topham.kicks-ass.net/gallery/album04

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I ported a set of '70 351w heads and wrote a post on the home porting forum on this site. In general, the heads were put on a 331 and i'm using a 282S Comp Cam (236 @ .050 and .528 gross lift). Horsepower (with full length dual 2.5" exhaust) is about 395 at the flywheel based on the last chassis dyno of 313 RWHP. I used 20% drivetrain loss for a C4 automatic and a 9" rear to derive flywheel HP. Open header flywheel HP is most likely over 400 and 410-415 if I were to venture an estimate. I'll be going to the drags this year so i'll see what she does.

So long as your not building a big cubic inch engine or a full out race engine, you can achieve a nice running street engine with ported 351w heads. Use the 69's...better than the later heads you have.

_________________
Tracy Blackford: Corona, Ca
'65 FB Mustang 331 with H-beam 289 rods, KB 322's, 282S cam, fully preped 351W heads. Built C4 and 3.50 9" posi




<font size=-1>[ This Message was edited by: blkfrd on 6/7/05 6:08am ]</font>

I like the way Tracy thinks! I love old Ford iron.

Ray

My 70 351w heads were good for 11.70 in a 3100 pound car with a 306.The heads were mildly ported
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Its all about the combo.


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Ported factory head, when it's a GOOD port job, work fine on small cubic inch engines.

Trust me, I'm proud of my 289 heads, but I've got almost as much money in them as a stock set of aftermarket heads... and I put in a lot of hours of tedious work into them. I'd like to build another small cubic inch 289 headed engine, but I want to go faster, and there just isn't that much more room to grow with the factory iron.

If you plan on buying all new parts and getting all the fancy machine work done, you're dollars ahead to go aftermarket. If you have a cheap way to get machine work done, have a line on inexpensive hardware, or just want to grind away on a set you don't plan on doing a lot of work to.... by all means, grind your heart out! It is a very satisfying project. It's definitely horsepower earned and not just bought. [img]/phpBB/images/smiles/icon_wink.gif[/img]

Good Luck!
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