torn b/w iron gt-40s or afr165!

[Foxfan88]

AGH i cant decide, i want to go alum then i consider gt-40s will help alot and cost less.

But i want to have a step up, be different, my friend has a HCI with ported Pheads i duno i just feel like goin aluminum....

plans for the engine are B-cam and cobra intake. I think the gt-40s would be a perfect match for them. but i also want to go aluminum, to save weight and make more power. but the alum heads seem like they migh be overkill for the B-cam.

The gt-40s will be much cheaper also.

i dont know, i cant decide.

Goals are a 12 sec street car.

post your advice!

 

[Grn92LX]

Go with the gt40's if all you want is a 12 second street car. The 165's are nice but why would you use a B cam with them? You can get used gt40's for around $400. New afr's are over $1300. The price difference isn't worth it for this particular combo.

JUst do valve springs in the 40's and have them clean up milled.

 

[DMAN302]

Go with the Gt40's and a nice port job from Tmoss..with the money saved over aluminum perhaps look at a better cam.

 

[bentley429]

Go with the gt40's if all you want is a 12 second street car. The 165's are nice but why would you use a B cam with them? You can get used gt40's for around $400. New afr's are over $1300. The price difference isn't worth it for this particular combo.

JUst do valve springs in the 40's and have them clean up milled.

This seems like some good advise FoxFan, if you were running a different cam, had the extra $$ and wanted abit faster car it would be a different story. But for your setup i looks like GT40s would be a good choice, I have also heard good things about the Thumper E7s . Another idea is to put the gt40's on and for that little extra run a 75 or 100 shot, used kits go for $400 easy. Good luck!

 

[stang8urimport]

You really can't compare GT-40s to AFRs... They're in a different league... If you want 30-40 hp gain, get the GT-40s... you want 90+ HP gain (with the right combo), go with the AFRs.

 

[dragnazz5.0]

yeah, id go with the gt40s and possibly talk to thumper about getting a set of ported ones. but if you decided on the afrs dont put a b cam in it. atleast go with an anderson cam or a trickflow cam

 

[Roland69]

The 40's will kick the SOTP gauge up a few notches and are good to help you get in the 12's

 

[maverick0716]

Another good thing about aluminum heads that I don't think anyone has mentioned is weight savings. You would save 50 lbs. off the front end (where it's needed most) if you go aluminum. In this case however, the other guys are right.....if you keep the b cam then you might as well get Gt-40's which are also a very good head.

 

[rd]

The iron GT40's should get you into the 12's without two much trouble. I have 2 sets of them and there is probably a lot more potential in my main setup, if I ever get to tuning.

All that said, I decided to go to AFR's. Sometime this summer I should have them on there. They should also carry next years stroker also.

 

[Tonys96Cobra]

For what you want out of it, go iron! You can always spray it or s/c it later if you need more.

 

[Foxfan88]

i've also heard that iron heads are better for a supercharger, at least for a mild build up, since the alum head will dissapate heat more, the engine will emit more heat and heat up the supercharger and the incoming air.

the iron head will contain the heat and will give off less.


are all the gt-40 heads the same, like are the actual 93 cobra heads the same as say a lightning head or the early explorer head?? i've heard some have the 1/2" bolt holes.

also looking at some flowcharts i got to wondering, how well will a FULLY PORTED TO THE MAX set of gt-40s flow? say as good as the 165s or performer heads??

 

[stang8urimport]

i've also heard that iron heads are better for a supercharger, at least for a mild build up, since the alum head will dissapate heat more, the engine will emit more heat and heat up the supercharger and the incoming air.

the iron head will contain the heat and will give off less.

:SNSign:

 

[Foxfan88]

:SNSign:

uhhh...makes sense to me, if an alum heads gives off more heat and makes the engine bay hotter, making the blower hotter wouldnt that just hurt it? i mean it wouldnt be horrible but in theory?

 

[Roland69]

a set of iron 40's worked would be a good gain. Your theory makes sence to me but the air would be moving around so much that you would hardly tell the difference in temp's.

 

[DMAN302]

uhhh...makes sense to me, if an alum heads gives off more heat and makes the engine bay hotter, making the blower hotter wouldnt that just hurt it? i mean it wouldnt be horrible but in theory?

Your thinking about it the wrong way..you want the heat to disapate. Your thinking, like the sun does, the heat from the heads will radiate out and heat up the components in the engine bay...not the case. The 'supercharger' would experience no ill effects from aluminum cylinder heads...in truth they would be an advantage in making power with any engine addition.

 

[2000xp8]

Don't waste your time or money on gt40's. Or the b cam. Especially if you are considering afr's. If this was more like ported e7's vs gt40 irons, i'd say do whatever, but it's obvious you are going to want more power.

You'll be back in no time for more power.

You don't "need" afrs to make a very potent combo, you can get a set of used gt40x, edel rpm, or Twisted wedges. Probably around $900 or less.

Gaskets, pushrods and other misc parts add up, so you don't want to do this twice.

Headwork on a $400 set of gt40 irons, would likely add up to the cost of buying aluminum heads.

 

[eric88gt]

I'm gonna be one of the very few here to say go ahead and run the b-cam if you can get one cheap. I've been running 165's and a b-cam with a cobra intake for a 3 years now. Still speed density, with stock injectors and fuel pump, it's best is a [email protected]. That was with a 1.78 sixty foot. Just because it's old and cheap does not mean it doesn't work, it may not be perfect, but it's not as bad as people make it out to be.

 

[352Ford2]

Don't waste your time or money on gt40's. Or the b cam. Especially if you are considering afr's. If this was more like ported e7's vs gt40 irons, i'd say do whatever, but it's obvious you are going to want more power.

You'll be back in no time for more power.

You don't "need" afrs to make a very potent combo, you can get a set of used gt40x, edel rpm, or Twisted wedges. Probably around $900 or less.

Gaskets, pushrods and other misc parts add up, so you don't want to do this twice.

Headwork on a $400 set of gt40 irons, would likely add up to the cost of buying aluminum heads.

I have a 350 bucks into my gt-40 heads total including purches price (fully ported by me, new springs, retainers, locks, couple valves, valve job, etc) Just have to be smart with what you buy, try to avoid something that doesn't need to much machine work and do the porting and as much of the work as you can yourself.

not a bad bang for your buck

thermal proberties of iron and al. AL disapates heat much beter than irons heads (you welders out there will agree) whitch is good and bad. As we all know from Thermodynamics heat is energy and when it leaves the combustion chamber it is lost HP. IF everything is equal an identical iron headed engine will make more power, but in this world we are limited by many things. The biggest things are fuel and the fact that most al heads are designed better than their iron conterparts. The fact that al heads bleed out heat alow you to run more cr, boost, etc, without problems with pre-igition on a given octane/specific gravity of fuel.

 

[maverick0716]

I'm gonna be one of the very few here to say go ahead and run the b-cam if you can get one cheap. I've been running 165's and a b-cam with a cobra intake for a 3 years now. Still speed density, with stock injectors and fuel pump, it's best is a [email protected]. That was with a 1.78 sixty foot. Just because it's old and cheap does not mean it doesn't work, it may not be perfect, but it's not as bad as people make it out to be.

Those 1.72 rockers help that cam a lot though. If someone was going with a B-Cam, I would only recommend 1.7's (or 1.72s) with it......screw 1.6 rockers.

 

[Foxfan88]

i have 1.7s, should put the lift at about .512 not sure tho