[race4food]

I've read through the entire thread but the debate about the navigator heads vs the 03/fr500 heads is still in the air.

What is the concensus about the Navigator heads? Are the ports just too big?

 

[johnny-longtorso]

i am only 20 got a lot of life left lol ...

Sorry for digging up such an old post - but if that's you in the pic and you're looking for a long life in the service industry I'd highly suggest you consider eye protection when working like this. I was an ER orderly for 2 years, and when you get something in your eye about the only thing they can do is dig it out, and to say it's an unpleasant process is something of a grand understatement. The tool is called a "spud", and in a supreme bit of irony looks quite like tiny carbide burr.

I've only ever worked a set of iron 351C heads, but know that crap was flying _everywhere_.

Just tryin' to help.....

Don

 

[Screamn03]

What is the concensus about the Navigator heads? Are the ports just too big?

The way I read it is the exhaust port on the navi is too small and requires alot of work (money) to get them to 03+ status.

 

[Induction Concepts]

Yea, what would be nice is if one of you 'head gurus' would make up a summary of these 13 pages, something short and sweet and then modify the very first post in this thread to include that info, to save people from having to wade through this much info. Then they can always wade in if they WANT to. Too simple no?

 

[Screamn03]

A summery:

Here's a link to an article that appeared in 5.0 last year:
http://www.svtperformance.com/forums/showpost.php?p=2173843&postcount=6

I'll add what you said to the things to do list:
http://www.modularfords.com/showthread.php?t=7434

Everything you said Rad is being worked on, just a matter of time.

 

[robaccobra]

4v port heads

There still are no aftermarket heads for the 4V Modular, besides the FR500 heads from Ford.

Here is a list of the current offerings

• 93-98 Cobra/Mark VIII heads (I believe they are the same head
• 99-01 heads
• Navigator heads
• 03 Cobra heads
• FR500 heads

With that being said, which heads are the best? Do some work better with blown applications? I have been told the 99 heads flow less but have more velocity than the early model Cobra/Mark VIII heads. I have also been told that the 03 heads are best out, they have rectangular ports instead of oval ports. Also, does porting help these heads much?

This seems to be a really good topic, and I hope some of you modular gurus out there can help answer the questions here, and possibly back up your answer.

hi the expiriense I have porting heads is that the only way to find out wich is best, is by using a flow bench. all so the porting in invers D works like a dream but u have to spend to much work, all so no all the time biger ports works better in other words if u dont have a flow bench u can lost insted of wining, if u want just polish the ports and get of all the ages that way i am shure u will dont regreat. sorry my english is a little rusty.

 

[Madferraristi]

Head Identification

Can anybody help me ID my Navi heads.

The engine that they came from bears a 12/99 build date but there are some parts anomalies.

The casting number on the heads is RFXL 1E6C064AE.

 

[Faststang]

NorCalCobra That is nice looking port work. Do you have flow numbers on those heads?

Agreed that is a great job bro!
IMHO though I would leave the intake side with at least a 120 grit finish to help fuel atomization. Especially in the B heads where port velocity is low on the injector side!

Good stuff though!

 

[XR8TED]

Sorry for digging up such an old post - but if that's you in the pic and you're looking for a long life in the service industry I'd highly suggest you consider eye protection when working like this. I was an ER orderly for 2 years, and when you get something in your eye about the only thing they can do is dig it out, and to say it's an unpleasant process is something of a grand understatement. The tool is called a "spud", and in a supreme bit of irony looks quite like tiny carbide burr.

I've only ever worked a set of iron 351C heads, but know that crap was flying _everywhere_.

Just tryin' to help.....

Don

Yeah that was a older pic I have since learned my lesson well not from porting but after work I was on my way home and a piece of cast iron went into my eye and had to get it drilled no fun for sure.. I use saftey glasses a real dust mask and i wear my ipod under my ear phones.. I never used to like that but since I am now the head cylinder @ R.M.I so I can't afford to miss work cause I did not protect myself.

 

[XR8TED]

Agreed that is a great job bro!
IMHO though I would leave the intake side with at least a 120 grit finish to help fuel atomization. Especially in the B heads where port velocity is low on the injector side!

Good stuff though!

I never really post finished product pics to often... I usually go over the port until it is completly smooth and go back over it to ensure the port is uniform.. But there is a textered finish in the end...

 

[XR8TED]

On another note I have been doing tons of testing on the #3/04 heads as far as chamber work... We have just got are newest toys one from joe mondello we recieved his newest version of the wetflow setup and also a prototype tumble port meter from Audie tech... Once we get this up and running we can go deep into r&ding these things.. Here is some flow numbers from my latest stage 1.5 street heads...

 

[ATOMonkey]

Here is the data from this thread and others concerning cylinder head flow. I've tried to compile it all as best I could. Hope it helps.

 

[ITS BACK]

I know about the work needed to get the ports to match up between the 05 GT's head and 03-04 Mach/99-01 Cobra intake, but what about the bolt locations? How far of are they?

 

[fpv_gtp]

great info

cheers

 

[aleborjas]

is there any adapter for the heads to use a 99 up supercharger or intake on my 98 cobra stock headed!

 

[PGreenSVT]

is there any adapter for the heads to use a 99 up supercharger or intake on my 98 cobra stock headed!

Yes, they are called tumble port heads and you can find them at a variety of price points depending on the year.

 

[aleborjas]

where? i need them

 

[markolson]

Yes, they are called tumble port heads and you can find them at a variety of price points depending on the year.

He's saying you need to do a head swap.

Aleborjas, you have been posting this question all over the internet. The answer is that nobody makes an adapter of any kind that will let you use a newer twin screw supercharger or intake manifold on our B-heads. Nadie hace cosas. Lo siento.

 

[97DOHC]

Question: Is there a market for Navi heads? I know that they flow great at high rpm and in ported form are probably one of the best heads to strap to a 4.6L. I may have stumbled upon a graveyard of these heads with a gentleman who states that he has about 100 of these heads. I am going tomorrow (hopefully) to check out these heads. Do people desire these heads? Please let me know via PM if you are interested or if you know someone who is. Thanks all

 

[97DOHC]

Nevermind my last post...the guy had countless 5.4 SOHC Heads...no dice