Ok, so I made a post the other day thinking I had gt40 heads and got a bunch of good information.. but I just found out that I have e7tes.. so now I have new questions, keep in mind, I know about the big 3 (cheap, fast, reliable) and I want to go more cheap and fast...

1. Heads: I could buy gt40s or even gt40ps, but I could also buy some aluminum heads with valves and springs, but then I know I'd need all kinds of other **** (rockers, studs, guideplates, girdles etc etc) to get em running, wouldnt I? Do gt40ps flow enough air to make 300whp with supporting mods (cam, upgraded valve springs, roller rockers, dual plane intake, open 421s, and a spot on tune)?? How much should I be ready to spend to make 300 whp?

2. Carb cfm: So I get the basic idea; within reasonable sizes, smaller carb = better throttle response, more midrange torque, less top-end power, and a bigger carb = less throttle response, less midrange torque, and can make a little more top end power... I once thought that at a high altitude I just want more more more air everywhere that I could, but after thinking about the big carb/small carb thing I started realizing that the carb is the very end of the intake vacuum system.. in thin air, with a big fat wide open carb, it won't make enough vacuum to even pull air through the carb into the motor. At high altitude, I should use a smaller carb, so that vacuum will be stronger and the motor will really be able to get the carb sucking in air. Is this right? I live at 7200 ft and the track is at around 5500. I've been told anywhere from 500 to 750 cfm, I'm thinking 550-600 would be best after I did a little research, but I want to hear others opinions. keep in mind, 5500-7200 ft elevation and looking for the nice 300 whp mark

 

yeah doesn't everyone....until reality smacks them in the face, sorry cheap and fast don't belong in the same sentance.....try again

 

1. port the gt-40's, gasket match everything, tfs-1 cam and a rpm air gap, and all supporting mods at your elevation mid 13's maybe low if you can drive

2. move to sea level 600 cfm will be fine

 

If your stuck at that altitude , your also stuck with that air density and pressure.
supercharger will make believe you are at sea level..

 

haha yeah I'm aware of this.. I can cough up around $2,000 for cylinder heads, cam, distributor, intake, carb, etc, but I want to know if it's feasible to achieve my goals for less. I know that plenty of 5.0s make 300 whp naturally aspirated around here.. and this is going in an 86 mazda rx7, not a foxbody... anyway here's my current plan:
1. gt40p heads with ported intake runners, .03 oversized exhaust valves, upgraded valve springs, 1.6 roller rockers
2. tfs stage 1 roller cam
3. edelbrock performer rpm dual plane or ford racing victor jr single plane manifold
4. 550 cfm holley 4 bbl
5. summitracing HEI distributor
6. no a/c, underdrive alternator, fluidampr balancer
7. running a t5 through mazda 4.10 LSD

any problems or things that don't fit? or is this a solid setup that could have a nice balance of driveability and power? I don't care so much if I make exactly 300 as I care that I still have enough torque through the middle of the rev range and a linear or close to linear power curve. Is this a good setup for this? It's for a drift car lol so help me out cause I chose the ford motor

 

I don't think there is any way to know for sure if you will make 300hp or even how close you will be. If you know of some people up there that have a dyno sheet showing there numbers you could look to see what setup they are using.

And while it is not uncommon to see a 5.0 liter engine with some good bolt on parts get up to the 300hp range , the deciding factor here is your altitude . If you want to make good torque at that altitude you will surely want to keep your rpms high.

I would be highly suspicious of any claim of getting to the 300 hp range for 2 grand. Heads alone with all that work will likely eat up your budget in short order.

 

Of course if you skimp out and get all used parts with out any knowledge of previous use or build , there is a chance youll get lucky with some good parts . I just don't think its worth the risk in the long run.

 

Run a supercharger and call it a day. You need a lot of air

 

run the 600 carb just rejet it and use a lower hg power valve...do some testing with squirters and the linkage cam to open the blades faster or slower,,you will need to play with cam timing

 

Like was posted above, use a 600CFM carb and tune it from there. The last carbed cars ever built at Ford used a 600CFM carb.
I'd go a couple sizes smaller with the jets for a start and then maybe play with squirters to see what the car likes.
If you are trying to race at that altitude, use more gear than you think you need, like b4.30 instead of 4.11