Cobra Gt 40s

[a91what]

Under drive pulleys are pointless they weaken the charging and cooling system. for what 3hp.....

Gt40x heads are IMHO overpriced for what you get. better to get gt40p heads and headers. oh and a new cam.

 

[Stanger76]

No I'm not 100% sure they are untouched e7s. Fuel pump is stock for sure because he let me know it was but the injectors are not stock they are either 24 or 30s but I believe their 30s and u may be right I could be going backwards with gt40 iron heads. They did everything to the car that's been done except the nos which I had done so it seems tfs 170s would for sure be a upgrade and not to costly. I know it seems afr would be what everyone says to go with but for the price I'm thinking tfs. May be a dumb question but how do I go about checking valve clearance? And which tfs heads? I went on summit and seems they have about 10 different sets of 170s. Srry I know it seems I list another aftermarket part or upgrade each post. I should've written it down so I could remember it all.. when u get 40 it's harder to remember then when I was a young buck

 

[Stanger76]

I'm trying to avoid going in to change the cam unless it's absolutely necessary

 

[Gearbanger 101]

Under drive pulleys are pointless they weaken the charging and cooling system. for what 3hp.....

Gt40x heads are IMHO overpriced for what you get. better to get gt40p heads and headers. oh and a new cam.

I guess it depends on what you consider overpriced? Plenty of used examples out there. I paid $600 fresh out of the machine shop for my set. Good for 60hp over stock and knocking 50lbs off the front end of your car. The TFS and AFR's will admittedly make slightly more horsepower out of the box, but the difference isn't vast.

The "P's" no matter the condition are going to require a valve spring upgrade, new valve seals and a proper 3-angle valve job. Get a set with some miles on them and they might need guides too. Suddenly those "budget" GT40P's aren't so budget anymore? And in the end, you'll still be on the low end of the power scale compared to the rest.

You also need to consider how "on a budget" one is is going with the aluminum castings. The GT40X's will accept the stock rocker arms and bolt on right out of the box. No fuss, no muss. The TFS and AFR's will require a stud mounted rocker arm and pushrods upgrade no matter what.

Any of the aluminum heads are going to require a head bold reduced kit, as they're all drilled for 1/2" head bolts. So budget for that too.

It's all relative to performance per dollar, really?

 

[deathb4dismount]

why nitrous if it is only a street car?

 

[Stanger76]

Because it sounded really good about 7 months ago so I bought and installed the kit and have used it obviously on the street since it's not been to the track maybe 5 or 6 times. Also doesn't hurt to have when playing with some of the new Chevy's lol

 

[Stanger76]

I'm not saying it will never visit the track but even if it does it will be only occasionally.

 

[Stanger76]

What gain difference would it be between gt40x and tfs 170s? Would the tfs out of box be that much better then the x heads?

 

[Black1987]

What gain difference would it be between gt40x and tfs 170s? Would the tfs out of box be that much better then the x heads?

http://www.hotrod.com/articles/ccrp-1302-six-budget-ford-heads-that-work

 

[General karthief]

Between the heads tested there was only 20lbft tq and 15 hp difference. Looks like a matter of extra parts expense and future mods.
Please stop say'n 'nos', thats for teenagers that don't even own a car. At least thats my opinion, but then I'm older and grumpy!

 

[FoxMustangLvr]

Resale value too. Some people like to stick to Ford parts too so there's that. TFS is very popular with 5.0's and AFR too. It's up to you.

@karthief Nawz! Is that better?

 

[Gearbanger 101]

http://www.hotrod.com/articles/ccrp-1302-six-budget-ford-heads-that-work

So the TFS 170's bested the GT40X's by 18hp/11tq on an engine dyno, through a big breathing carb/intake and an open exhaust.

Now, switch that intake out for a more restrictive Cobra EFI upper and lower and add a full exhaust to the mix (not simply open header like the comparison above) then convert those numbers to SAE net and those differences are cut by about half.

Like I said, the TFS heads are better, but not by a huge margin.

Not sure if it would be a big enough margin for me to justify the cost of new valve train components to go along with it? But that's just me.

 

[General karthief]

Resale value too. Some people like to stick to Ford parts too so there's that. TFS is very popular with 5.0's and AFR too. It's up to you.

@karthief Nawz! Is that better?

YES

 

[General karthief]

So the TFS 170's bested the GT40X's by 18hp/11tq on an engine dyno, through a big breathing carb/intake and an open exhaust.

Now, switch that intake out for a more restrictive Cobra EFI upper and lower and add a full exhaust to the mix (not simply open header like the comparison above) then convert those numbers to SAE net and those differences are cut by about half.

Like I said, the TFS heads are better, but not by a huge margin.

Not sure if it would be a big enough margin for me to justify the cost of new valve train components to go along with it? But that's just me.

I agree with you, considering future mod, bigger, better, faster, more money!

 

[Gearbanger 101]

Resale value too. Some people like to stick to Ford parts too so there's that. TFS is very popular with 5.0's and AFR too. It's up to you.

@karthief Nawz! Is that better?

At entry level like this, one is really as good as the other. Some perform a little better than others, but their cost reflects that. Some are built to a higher standard than others and their cost reflects that too. Pick the one with the cost vs quality vs performance balance you can live with and buy it. If going from a straight performance stipulation, the AFR's and Trick Flow heads only really start proving their worth at a street car level in the 190-225cc ranges IMO.

....but then Ford has their M-6049-Z304A head, which is a pretty darn good choice too.

Lotsa different ways to skin a cat.

 

[Black1987]

So the TFS 170's bested the GT40X's by 18hp/11tq on an engine dyno, through a big breathing carb/intake and an open exhaust.

Now, switch that intake out for a more restrictive Cobra EFI upper and lower and add a full exhaust to the mix (not simply open header like the comparison above) then convert those numbers to SAE net and those differences are cut by about half.

Like I said, the TFS heads are better, but not by a huge margin.

Not sure if it would be a big enough margin for me to justify the cost of new valve train components to go along with it? But that's just me.

I was just providing a somewhat baseline for comparison. Never said either was better. Personally any of those heads will get the job done. Just shop around

 

[General karthief]

I was just providing a somewhat baseline for comparison. Never said either was better. Personally any of those heads will get the job done. Just shop around

I agree, just consider the cost of extras, are they not all pretty much bolt ons with the exception of rocker arms? None requires dedicated headers? Just wunder'n.

 

[Black1987]

I agree, just consider the cost of extras, are they not all pretty much bolt ons with the exception of rocker arms? None requires dedicated headers? Just wunder'n.

Push rod lengths also have to be checked. Depending on the head's design and valve size, PVC (piston valve clearance) will have to checked.

The only heads that I know of is the GT40ps.

But yes pretty much bolt on

 

[deathb4dismount]

Honestly if the op really wants to stick to his around $1000 budget, he already has pedestal mount rocker, I would stick with the ps and any money saved I would throw at the suspension, better yet throw the money right at it. I would rather drive a solid 215 hp car that puts the power to the ground than a sloppy 300 hp car.

 

[General karthief]

Honestly if the op really wants to stick to his around $1000 budget, he already has pedestal mount rocker, I would stick with the ps and any money saved I would throw at the suspension, better yet throw the money right at it. I would rather drive a solid 215 hp car that puts the power to the ground than a sloppy 300 hp car.

What is meant by 'sloppy 300hp car'?