Cylinder head porting

[CTGSTANG]

Hey guys! I've decided to break down the 40 year old original 302 and my first mod is to take care of the cylinder heads. I don't have enough money to buy a good new set of AFR heads so I'm leaning towards having the original heads ported, polished, new springs, and freeze plugs. How much HP do you think the porting will get me? As always guys, thanks for the advice!

 

[droptop73]

It depends on the rest of the engine work. If you use a mild cam and smallish intake, carb and exhaust probably not much. It all depends on your intent. Cleaning up the valve bowl and a good valve job can increase low lift flow, hogging out the ports will help high lift / high rpm flow.

 

[sm3570]

No need to pay someone to do a head job!

http://www.7173mustangs.com/thread-want-a-good-laugh

 

[Wolverine]

For what it is worth....

My pony car experience is:

73 Mustang Fastback, 351 2V Automatic. New until stolen, 1985

70 XR7 Convertible, 351 4V Top Loader, 1977-1980

73 Mustang Convertible 302 650 Holley, Hedman Headers, Weiand Intake Manifold, HIPO Heads(whatever that means).

Based on my experience(built by previous owner, run into the ground by me) I would not bother with the 302. New heads sometimes mean new exhaust, new manifold because the ports don't always line up. Sure, there are ways to get power out of it, but it is probably a lot easier to just step up to a 351 for an extra 50hp.

Be patient, find a cheap 351 block(W or C) and build it with 2v Cleveland heads. There are LOTS of guys here, droptop73 in particular, who can tell you exactly how to extract power for the street from this setup. Probably for a lot less dough.

If you do a search of partslist on the forum, you will see I am compiling a list of every single piece needed to build an engine. Copy to a spreadsheet and compute the costs....if you dare!!!

Good luck...

 

[Chris Womack]

I also rebuilt the 302 in my 71, and used the original cylinder heads too.

I did all I possibly could at the machine shop to improve performance:

* ported in bowl area

* street competition valve job

* enlarged valve seats

* oversized stainless steel intake and exaust valves, (the AFR heads are using 2.05" and 1.6" - mine were a little bit smaller)

* machine for srew in studs (for adjustable valves)

I thought the expense was acceptable at the time.

I also finished out the block with a good hardware, e.g., nice pistons and push rods.

I wanted a car that performed well and could still drive to college, so I used a Crane 260 duration cam ~ .440 lift and a Holley 600.

 

[sm3570]

Before the '72, my dad had a '71 that he built the 302. I'm not sure of the cost, but I know parts for the 302W are cheap and his '71 was a BEAST even with the "little" 302.

All I did was burnouts in that thing.

 

[MeZapU]

I ported some E7 heads, gave em a valve job and installed them onto my 85 GT. Gained .4 seconds in the 1/4 mile and three mph. That's on a much lighter car. You may see a 10/20 h/p improvement tops but don't expect it to be anything comparable to a set of aftermarket AFR's or the like.

If you need anything to the heads other than a valve job, start adding up h/p gains per dollar spent and those aftermarket heads start looking better and better.

 

[BigPinoyHunk]

for the coast of SBF heads, you are better off paying 1000 for aftermarket heads.

now with big blocks, you can come out infront with ported iron cuz of the cost of bbf aftermarket heads. i got fully all out porting and bigger valves on my heads for less than the cost of new heads by 25%.

i think people usually pay 1000ish for head porting which is about the cost of aftermarket assembled heas.

 

[Totalled]

If you can't afford aluminum, I'd yank a set of GT40's off of an Explorer.

 

[c9zx]

You can get these http://www.edelbrock.com/automotive_new/mc/cylheads/ford/sb_estreet.shtml for less than it would cost to (professionally) port, replace valves, guides, springs, retainers, keepers, and the valve job. You would need to buy studs, guide plates, hardened pushrods, head bolt bushings, and rocker arms. None of this is cheap. Before you do anything you need to decide what the end product is supposed to be and figure out if it is attainable given time and money constraints. If you decide to buy heads you need to do a lot of research to make sure they are a good fit to the other components and the end product goal. There are dozens of SBF heads available, not all will meet your needs (port volume, chamber volume, valve size, springs). Have a complete and realistic plan before you buy the first part. Chuck

 

[CTGSTANG]

My plan is probably 300 HP max throughout the entire project. This car will never be a screamer just want it to have some spirited fun. Keeping the C4, mild cam, cylinder heads to match with the current edelbrock intake and 600cfm carb. It's a rest cruiser. I dont want to get too deep into the engine yet since it will need paint in a couple of years and we will be moving for my work here within the year too.


Thanks to everyone for the advice! Those E-street heads look good for my purpose and will be looking for comparable ones on eBay.

 

[c9zx]

Which Edel intake do you have, the performer? The 300 HP is a realistic goal, maybe a little more. When you start shopping cams, get the flow data from Edel for the heads, if it is available. Consider a quasi-custom cam as it is not much more and will likely be a better fit to your particular set up. If you think you can live with headers, I'd suggest them. Stay with a "smallish" primary (1.5) and collector (2.5) size as you are looking for torque. HP is great but, in your set up, torque is what will make you smile. Consider a set of Tri-Ys. Old school but they work. Good luck with the car and the relocation. Chuck

 

[72fastback]

getting heads ported and polished with new seats and guides is more expensive than buying aftermarket. especially for the 302. I had my Cleveland heads completely redone. And I now I wish I got aftermarket heads. Don't get me wrong the 4v heads are great but I would of gained even more power especially low end with aftermarket heads.