heads, how much hp gain??
 

looking in the new Summit cataloge, they advertise GT40 heads, complete for $538.00. sounds cheap enuff...

185 cfm flow, 1.84 intake, 1.46 exhaust..

I know, way better than the current 86 heads..

what can i expect in the way of performance increases??

well, those are the GT-40 "P" heads. they are different than the GT-40 heads.
http://www.geocities.com/MotorCity/Pit/5755/gt40p.html

that link will help you know a little more about them. thay are a godd step up from what you have now but will require specific headers.

take care,
adam

thx for the link, looks like it's an affordable decent performing head..

Stock heads :150ish cfm

185 cfm flow, 1.84 intake, 1.46 exhaust.. GT40 P's

Aluminum Heads:,260ish, 270ish, 280ish just depends on which ones you get. Wait! And save up some more money, 90-100 cfm is well worth the extra money. TRUST ME.

Stock heads = 155cfm
GT-40P heads = 190cfm
Most aftermarket aluminum heads (Holley, Edelbrock, etc)= 220-230cfm
TFS and AFR 165 = 250cfm
Race heads = 260-280cfm

Stock intake = 135cfm
Explorer intake = 190cfm
Cobra/GT40 intake = 200cfm

The big flow aftermarket aluminum heads won't give you any hp over the GT40P heads if you don't have the rest of the setup to use them.

Quickest people running GT40P's? I think the Trophy Stock guys are down into the 11's pretty good, trapping over 110mph on them. Ford crate engines are rated at 320hp with them, and most people get an additional 20-30hp more than that with more aggressive aluminum headed combos. It's all up to you, but for a street car on a budget, the GT40Ps look damn good to me.

What's the next step up from the GT-40P heads (Price and performance-wise)? Not sure if I want to spend like 1000-1100 for some heads, but I can spend more than 550.

I have the BBK shorties, which don't work on the GT-40P heads (YAY!)...so that is another reason I would be opting for something else.

Is there a good medium between the two? If so, what kind of gains could I expect with my setup and what do they flow (cfm).

Thanks,
DoranW

Get yourself a Jeg's catalog. ;)

For a step up you may want to consider one of the following heads, all found at Jeg's:

Roush 200 cast iron: 200cc intake, 64cc combustion chamber, 2.02/1.600" valves = $399.99 each, assembled.

World Windsor Jr 180 cast iron: 180 cc intake runners, 58 cc combustion chambers, 1.94/1.600" valves = $397.99 each, assembled.

I run the Windsor Jr's and love them. I believe Summit carries the Roush heads. I know they carry the Windsor Jr. heads because that's where I bought mine. Try their website to compare prices.

Cool, that sounds pretty good :)...any ideas on gains (HP)? What should/could I run with a T5 and drag radials in the 1/4?

Thanks,
DoranW

These should get you 25 to 35 hp. I went to the twisted flow trick flow aluminum heads. I gasket matched the intake to the head using a ported version gasket. I now push 414 hp from a 30 over 351 Windsor, and I was getting 315 hp when running these heads on a 289.

I love the low end torque, and I love the high end acceleration. The only downside is that I tend to tear up the intake gaskets and then suck them. I get clouds of white smoke about once a year, but the intake gaskets are cheap, and fairly easy to replace on a 66 stang. 400 hp comes at a sacrifice.

If you go with iron heads, you will have less gasket failures, but it will ping on pump fuel unless you kill the compression. I have 10-1 compression and can run base regular fuel without pinging.

Try these heads if you need cheap. If you want to tear up the boulevard, the trick flow kick butt!

The Windsor Jr.'s work good for me.

a set of SVO GT40 heads currently for auction on ebay...

I have found Ebay motors to be a ludicrous place to buy the GT40 Irons. The old used sets routinely finish up over $500!!!

Find a set of used GT40's from a swap meet, have the cleaned up and put a little porting on them. The GT-40P's will require new headers as you have noted, I just didn't know if you had any mods. If you didn't, you'd be buying a set of headers and it wouldn't matter anyway :D

Most 180cc+ intake port heads are going to kill lowend.

As far as the alumium vs iron debate. Iron will be more reliable when it comes to gaskets, and fit. They will make more power than it's twin in aluminum. They do not allow you to run as much compression or timing as alumium heads, and they are much heavier than aluminum heads.

It's your call, but since you seem to be wanting to stick near the $550 area, the irons should be what you are looking at.

GT-40 Ported
GT-40P Stage 1 (requires new headers)
Windsor Jr.

Those would be the one's I'd recommend.