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Discussion Starter #1
After considering my options, budget, and being realistic about exactly what I am going to be using my 63 Falcon for, I have decided that rather than going for expensive aluminium Trick Flow 58cc TW heads, I will instead go for the plentiful, cheaper, milder, more tried and true GT40Ps (kind of like this) Should be more than enough pep for what I'll be doing with the car!

Its on the stand, in the build up stage. I currently have:
'88 5.0 Ford block, .030" over
TFS Stage 1 cam
Block decked -.006"
0.47" Fel-Pro head gasket compressed thickness
GT40p heads 59cc with uprated springs (probably get the Trick Flow spring kit)

I have not chosen pistons yet (the old ones are knackered as someone rebuilding the engine before I bought it fitted incorrect shallow rings to them!! A mess!!), so wanted to hear what pistons people recommend I use. I am leaning towards the KB311 pistons, as they are compatible with the Trick Flow Twisted Wedge heads so in the event I later on decide to change to these heads, I have the right pistons already fitted. And the +4cc pistons get me to around 9.3-9.5:1 compression ratio.
But I read people saying not to run hyper pistons, and the KB hyper is particular get a bad rep? Is this only the case if you're racing (which I won't be), and putting nitrous through it (which I won't be)?

I don't mind choosing OE equivalent replacement cast pistons like Speed Pro or Sealed Powers offerings to be honest, as there's plenty of guys using stock flat top pistons with these heads and cam with good numbers. How to these stack up, as they always seem popular? What piston would best match the factory OE ones? My existing pistons have around about a 1.600" comp height. No notches, no valve reliefs. I'm happy to shave the GT40p heads to up the compression a bit if I really have to.
I just want some cheap-ish, good pistons that will work the same or a bit better with the GT40p heads (59cc or a little less if I skim them) than the stockers.

My other question was: I have set of 1.6 Lunati Roller Rockers, which are on 7/16" studs. If I run the GT40p heads, is there any way I can run these rockers? I know you can get a 3/8" stud conversion kit for these heads, but I don't see anything for 7/16". I know I have the option of modding them heads for these studs if needed, but is there a 7/16" conversion kit available? And if there is, is it any good, or is the rocker geometry all over the place?

Thanks for reading! I value your help and advice folks!!
 

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I own a 65 mustang with GT40P heads. Our engine bays are same and what I can tell you don't even waste your time. By the time you get the valve job done on the heads you could have saved a bit more and got a better set of heads. I leaned on a friend and he machined them, milled them and put better springs in them. I have roughly 300 in them. And still they suck. Not as bad as E7s. But still suck. Once I had my awesome GT40P heads installed I ran into header issues. Because the plug have a different angle no headers would work ether. The only headers are JBA or Sanderson and wow 400 for a set of 1 5/8 primaries, that also sucks. And unlike fox mustangs that have ample engine bay space you will ht the falcon's shock towers. Valvetrain be damned.

The only way your going to get 7/16 rockers on that head is if you machine them to use studs instead of pedestals. 7/16 studs on a GT40P heads is the perfect example of lipstick on a pig.

Now I didn't say it couldn't be done, I did and there is no way in hell I would ever do it again. Big waste of money. Should have saved a bit more and picked up a set of AFR 165. And bought cheap headers.
 

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I have been using Speed Pro hypereutectics in my 302 for years without any problems. And they have had several bottles of nitrous sprayed to them. Basic H273CP.

They don't have the dual intake reliefs for Twisted Wedge heads, but the shallow intake valve angle of the TW head typically doesn't need a relief with that cam.


I wouldn't put the money into a set of P heads to convert them to stud mount. Stay with a pedestal rocker. The stock ones aren't bad but some of them won't clear the retainers of the TFS spring kit.
 

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Discussion Starter #4
I own a 65 mustang with GT40P heads. Our engine bays are same and what I can tell you don't even waste your time. By the time you get the valve job done on the heads you could have saved a bit more and got a better set of heads. I leaned on a friend and he machined them, milled them and put better springs in them. I have roughly 300 in them. And still they suck. Not as bad as E7s. But still suck. Once I had my awesome GT40P heads installed I ran into header issues. Because the plug have a different angle no headers would work ether. The only headers are JBA or Sanderson and wow 400 for a set of 1 5/8 primaries, that also sucks. And unlike fox mustangs that have ample engine bay space you will ht the falcon's shock towers. Valvetrain be damned.

The only way your going to get 7/16 rockers on that head is if you machine them to use studs instead of pedestals. 7/16 studs on a GT40P heads is the perfect example of lipstick on a pig.

Now I didn't say it couldn't be done, I did and there is no way in hell I would ever do it again. Big waste of money. Should have saved a bit more and picked up a set of AFR 165. And bought cheap headers.

Thanks for your reply Gregor. I guess it boils down to how I intend to use the car though, and how the heads compliment the other parts in my combination. I don't plan to race the car, stroke it or boost/spray it, and simply have not got the money for Trick Flows or AFR's, nor can I justify the extra cost when that money could be better used to go into the rest of the car.
I have already read enough articles, tech features and forum posts about Gt40p/dual plane intake/1 5/8" header/TFS1 cam 302 ombos to convince me this route offers the right combination of usability, cost and performance for me and this particular car.

I certainly agree the 7/16" RR's are overkill though, and are indeed lipstick on a pig! I'll probably sell them and either use the stockers or, more likely, buy a set of pedestal roller rockers for GT40P's instead.
 

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Discussion Starter #5
I have been using Speed Pro hypereutectics in my 302 for years without any problems. And they have had several bottles of nitrous sprayed to them. Basic H273CP.

They don't have the dual intake reliefs for Twisted Wedge heads, but the shallow intake valve angle of the TW head typically doesn't need a relief with that cam.


I wouldn't put the money into a set of P heads to convert them to stud mount. Stay with a pedestal rocker. The stock ones aren't bad but some of them won't clear the retainers of the TFS spring kit.

Good advice, thank you. Are you saying you used H273CP's with GT40P's or TF heads?
 

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Good advice, thank you. Are you saying you used H273CP's with GT40P's or TF heads?
I use them with 2.02 Edelbrock Performer RPMs, they do not have the TW specific intake reliefs. They should have a mile of clearance with P heads and a TFS stage 1 cam.

But due to the shallow angle of the intake valve on TW heads, it is very common for them to still clear with smaller cams when used with normal pistons.
 

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I'd suggest a ProMAXX head with a set of Wiseco PTS pistons. 491.00 for the pistons wit rings. About 850.00 for the heads, ready to run.
 
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