GT-40 or AFR 185 ??

[RangerSVT]

Poll time

First, a little background... Some of you know I have a V8 powered 02 Sport Trac using a 99 ex for a donor. I'm planning a big boost in power, but am undecided on which set of heads to run. I will be using my 89 mustang block (currently has about 120k miles, but will get freshened up with new bearings and gapless rings), ported and polished GT-40 lower intake, custom adapter mounting a ported and intercooled eaton M122, and either a P & P GT-40 head with the valves opened up to 2.05/1.60 (or as close to that as I can get) or a set of AFR185 heads. The cam is slightly over stock, but I'm thinking of going with the FMS X cam. This is a 4wd truck, will have an upgraded 4R70W, will be used for towing and occasional light wheeling but 90% of its life will see street use. Not taking it past 6k rpm, but it will see anywhere from 10-20 psi boost levels. My ST is already SCT tuned and will get a custom tune once built.
I don't want an all out hotrod or dragrace machine, but I do want a good balanced setup with years of reliability.

Now for the question, do you think I should go with P&P GT-40 head with larger valves or run the AFR185 heads? What are your thoughts on each, and why?

SVT

 

[Hahnsb2]

GT40s are said to lift easily under not much boost...

 

[RangerSVT]

Dasfinc ran 8-9 psi boost on his 90k motor for a few months with no problems, either way, as I didn't mention, I'll be using copper head gaskets and ARP head studs, but thanks for the info, I didn't know that

SVT

 

[Hahnsb2]

Dasfinc ran 8-9 psi boost on his 90k motor for a few months with no problems, either way, as I didn't mention, I'll be using copper head gaskets and ARP head studs, but thanks for the info, I didn't know that

SVT

A recent discussion.
http://www.theturboforums.com/smf/newbie-tech-forum/critique-my-302-fox-set-up-for-the-newbee/

 

[RangerSVT]

A recent discussion.
http://www.theturboforums.com/smf/newbie-tech-forum/critique-my-302-fox-set-up-for-the-newbee/

Good reading. I still have the E7 heads, you think they would be better than the GT-40's with a P&P plus larger valves (economy route) vs the AFR185's? Either way, I'm thinking the AFR's are the better choice, but also the more expensive way. I'm looking at about 1500 for the AFR's, and probably half that if I go the other route, P&P + larger valves on stock heads...

SVT

 

[Hahnsb2]

Sorry, don't know too much about the 5.0, just that I've come across multiple accounts of GT40s lifting. How much power you looking for? Past 500whp the stock block is a time bomb anyways. Aluminum heads will tolerate more boost/timing since they dissipate heat better.

 

[RangerSVT]

I'm not planning to go past 500, but I also plan on squirting the pistons to help dissipate heat and with boost. I'm also thinking of water meth shortly after its running, not for more power, but for more reliability and fuel economy...

SVT

 

[Tominator]

Boost never saw a set of heads it didn't like!

You'll be very lucky to see 12PSI out of either setup.

GT40X has less flow that the AFRs, but the more restriction the more boost.

I'd get a custom cam aimed at torque and concentrate on that instead of HP numbers. Under 4000RPM the difference in HP numbers will not amount to much and even to get to 450HP you'll need a redline near 6500 or above and if you give the Eaton enough pulley to go that high you'll sacrifice some boost down low.

You have an automatic tranny and need to upgrade the convertor unless you go for torque down low as possible.

Meth is for HP and not economy BTW.

 

[RangerSVT]

I'm after more unrestrictive flow rather than watching the boost gauge climb, and I'm building more for torque than HP, since that's primarily what the intended use will be. Thought of stroking, but that combined with the Eaton will be way over the safety mark for the block. I looked at the rated rpm's which turned my attention to the X cam, it has a lower operating range than the rest, but a good RV/torque cam is what I'll be after. I'll be upgrading the trans internals as well as converter, and on the water meth, most use it for power, but I've read a couple times that it helped some in the mpg's. Mostly wanting to lower intake temps and see about upping the mpg's.

SVT

 

[Tominator]

but I've read a couple times that it helped some in the mpg's. Mostly wanting to lower intake temps and see about upping the mpg's.

That's sales literature. Meth injection DOES NOT lower the intake temperature any appreciable amount on a street motor. All it's benefits are in the combustion chamber.

The water does nothing until it turns to steam and absorbs heat. The methanol raises octane allowing increased timing. Most run a 50/50 ratio but only during higher RPM operation and use a boost sensor of some kind to activate the pump. A warning light if low on meth and an activation light to tell you it's working.

You will need a method of tuning...I use a PMS.

Additional gauges are required. Wide Band O2 and IMHO a fuel pressure gauge to be safe. Don't forget a boost gauge!

IMHO anything over 6lbs and you'll need all this in addition to the motor work though the internals really need nothing fancy.

 

[RangerSVT]

That's the main reason why I chose to use my mustang block over the ex block, it already has forged pistons. And the gauges will be in the truck, I have a narrow band autometer af, but I'll get the wideband setup before I start this monster.
Guess I need to do more research on water meth. I don't plan or intend to run in the upper rpm range(4-5k mostly except for when I get the happy foot syndrome, even then it'll stay below 6k). Now I'm thinking I may not run water meth. I really want this to be a reliable setup, safe operating range and as efficient as possible.
Thanks for all your input, I really appreciate it and learning from everyone's input...

SVT

 

[Hahnsb2]

Water/meth does lower IATs (only when active of course) and gives you a bigger safety margin (and of course allows a more aggressive tune) but it won't increase economy because it should only be active under boost, and if you're in boost, you're not getting economy. I'll be running it on my Dakota since I have no IC, if I had a roots/screw blower I'd certainly run it too.

 

[badmts]

They don't mess around in DYERSBERG .If you are going to show up at the Sonic out on the by-pass you better have a 347 minimum and you need to SPRAY that bad boy,but if you only want to talk smack and bench race the high school kids at the Sonic on St.John st. then the small heads and little motor should be ok

 

[RangerSVT]

I'll have to look into it. As far as sonic goes, decent food, decent scenery (sometimes), but I'm not building a fast food competitor, even though I'm still a teen. 20 years ago I used to street race, but I've cleaned up one too many wrecks in my life and learned people's lives ain't worth the risk. I'm building this is for me.

SVT

 

[Jfive]

Here is an article I suggest reading to help with your decision. http://www.airflowresearch.com/articles/article087/A-P1.htm