Gt40 vs Flotek heads

[Squarewheels287]

Wondering if anyone has or knows much about the Flotek heads. Currently looking around for a set of gt40 heads but around here they seem pretty rare, and the ones that do pop up are right around the same price as the Flotek heads, wondering if they'd be a good replacement for the gt40 or if they are less than stellar.

 

[franklin2]

Never used them before. But they already have screw in studs and guide plates. That would sell me on them. How are you going to adjust the valve train on your GT40 heads? Try to use shims under the bolts? Original Ford heads of any flavor are not that great. The reason chevy engines are so popular for racing.

 

[Bigmatthew86]

I was just in the same boat. I have a 96 Explorer engine in my Ranger so I already had gt40’s. If I didn’t have them I would opt for some aluminum heads. You’ll need springs for the gt40’s so it will cost more than just the heads. In my research it looks like the best china heads are the afr enforcers. Castings all seem to be the same but afr uses better parts in them. If you’re having to pull the heads I don’t think I’d go through the work for iron heads. Unless you find some that have been worked for a great price.

 

[Squarewheels287]

Makes sense, I'll probably go for one of the entry level aluminum heads unless I stumble on some gt40s that are a steal. Just got a running but higher milage motor, figured it would be easier to freshen up and do some upgrades before I install it.

 

[19Walt93]

Never used them before. But they already have screw in studs and guide plates. That would sell me on them. How are you going to adjust the valve train on your GT40 heads? Try to use shims under the bolts? Original Ford heads of any flavor are not that great. The reason chevy engines are so popular for racing.

Ford engines have non adjustable valve trains because they aren't prone to cam failures like grenades/SBCs. Once the lifter preload is set, it stays set. I know Chevy engines are popular because of all the hours I spent standing around in the staging lanes while the guts of another SBC were cleaned off the strip.

 

[Bigmatthew86]

If you have the engine on a stand I’d do everything now. Timing set, water pump, gaskets, hoses, heads, cam. Do it all now, so much easier than in the car. While you can do most in the vehicle it’s so much easier out. I’d probably run the enforcers with the smaller valves so I didn’t have to worry about notching the pistons. They look like they flow pretty well out of the box & can be ported to preform very nicely if you wanted.

 

[franklin2]

Ford engines have non adjustable valve trains because they aren't prone to cam failures like grenades/SBCs. Once the lifter preload is set, it stays set. I now Chevy engines are popular because of all the hours I spent standing around in the staging lanes while the guts of another SBC were cleaned off the strip.

I am not knocking Ford engines. They are what they are. Make decent power and will get you there reliably. But if you want to start messing around with the camshaft or go to larger valves, in the old days it was very costly doing all the machine work to modify the Ford heads. Your only choices were to pay a bunch of money to the machine shop, or try and retro fit 351c heads onto the small blocks.

Now the aftermarket has stepped in, if you want to make any power with a Ford engine you should change the heads to aftermarket with the adjustable valve train, larger valves, modified combustion chambers, etc.

 

[19Walt93]

My Mustang weighs 3320 lbs with me in it and runs 13.8 @ 102 mph on street tires. It has an 86 roller cam short block, Speed Pro pistons, ported GT40 heads, a mild(210/218@.050) Isky cam, and a Performer intake with a 600 Holley. Other than the ones with SS emblems, I beat every early 2000's, bathtub shaped Camaro I raced. 80's and 90's 350 Camaros were no competition at all unless highly modified. Aftermarket heads are absolutely better than most stock heads but my wallet wasn't that fast.

 

[JoshT]

ported GT40 heads,

That's the one I'm trying to decide on. I'm going to have two sets of GT40 heads and two intakes.

I know that aluminum heads would probably be a little lighter and offer a little more (talking budget aluminum here) performance over stock iron heads, but they also come with a price tag. I think I could get a set of GT40s and the intake ported for what a set of aluminum would cost and get more performance, but loose the weight advantage. I know ported aluminum would be best, but I'm not paying for aluminum heads and to port them.

So

ported GT40 heads + ported GT40 intake

-vs-

Stock cheap aluminum heads + stock GT40 intake

I kind of want a stock under hood appearance (ignoring that Ranger didn't come with 5.0) so really leaning towards the GT40 heads.

 

[franklin2]

That's the one I'm trying to decide on. I'm going to have two sets of GT40 heads and two intakes.

I know that aluminum heads would probably be a little lighter and offer a little more (talking budget aluminum here) performance over stock iron heads, but they also come with a price tag. I think I could get a set of GT40s and the intake ported for what a set of aluminum would cost and get more performance, but loose the weight advantage. I know ported aluminum would be best, but I'm not paying for aluminum heads and to port them.

So

ported GT40 heads + ported GT40 intake

-vs-

Stock cheap aluminum heads + stock GT40 intake

I kind of want a stock under hood appearance (ignoring that Ranger didn't come with 5.0) so really leaning towards the GT40 heads.

You still didn't say how you are going to adjust the valves if you need to on the Ford heads. Order shorter or longer pushrods?

 

[19Walt93]

You still didn't say how you are going to adjust the valves if you need to on the Ford heads. Order shorter or longer pushrods?

Shim them for correct lifter preload and forget them. It' ain't a Chevy, the cam isn't going to wear out fast and require readjustment.

 

[Bigmatthew86]

I’d sell the gt40’s & put that money towards aluminum heads. This is coming from a guy with gt40’s on his truck in the garage. If you have 2 sets to sell you should have at least $500 in heads. Run the gt40 intake, get the lower ported if you can swing it. If not run it as is & port it later if you want. It looks like the afr enforcers flow more out of the box than ported gt40’s & you lose 50lbs off the front end. I’ve seen several sets of twisted wedge heads on marketplace in the $12-1400 around here as well. So you’d probably be happy with the 40’s but you’ll probably end up wishing you’d have gone bigger. You’ll need springs & pushrods anyway. So if you get them ported you’ll end up close to the $1000 mark I bet.

 

[85_Ranger4x4]

Make sure you go with a good head, things can get lost in translation when you cheap out on heads. Guides not sized right or wear fast and you get a smoker, slave labor didn't size the hole right and it drops a valve seat at 6k rpm... all of the sudden your cheap heads ain't so cheap.

Shim them for correct lifter preload and forget them. It' ain't a Chevy, the cam isn't going to wear out fast and require readjustment.

I totally floored a 60yo coworker of mine when I did my V8 swap, he couldn't belive a boring old crown vic 302 had a high tech roller cam lol.

 

[franklin2]

Shim them for correct lifter preload and forget them. It' ain't a Chevy, the cam isn't going to wear out fast and require readjustment.

What do you do if the pushrod needs to be shorter? A shim won't fix that. Shave the heads to true them up, if you deck the block any, aftermarket cam and a valve job, any one or a combination of those could throw your lifter pre-load off.

It's a big problem everyone overlooks until they try to start the engine and it's won't run or runs rough. Take a compression reading and some of the cylinders are low on a just rebuilt engine because some of the valves are hanging open. But sometimes the moon and the stars align, and everything is ok.

 

[19Walt93]

What do you do if the pushrod needs to be shorter? A shim won't fix that. Shave the heads to true them up, if you deck the block any, aftermarket cam and a valve job, any one or a combination of those could throw your lifter pre-load off.

It's a big problem everyone overlooks until they try to start the engine and it's won't run or runs rough. Take a compression reading and some of the cylinders are low on a just rebuilt engine because some of the valves are hanging open. But sometimes the moon and the stars align, and everything is ok.

If a pushrod needs to be shorter a shim will absolutley fix it, if a pushrod needs to be longer it's a little more work- but you're only going to do it once. I rigged up a measuring device with my combination square so I could check pushrod length-which usually varies some- and move them around as needed. Worse comes to worse, if you own the GT40 heads a set of adjustable pushrods or rockers would be cheaper than heads. Ford used to sell .060" extra long pushrods if you want to set preload with shims.