As the title states, I am getting ready to put a stock mustang 5.0 H.O. cam in an explorer 5.0 with gt40p heads. I have read that the stock explorer valve springs are weak, so I am going to try and assemble the heads with the springs from a set of H.O. E7 heads. What I need to know is...
What is the installed height and presure specs. for the mustang?
What is the lift of the mustang H.O. roller cam?
What is the spring presure at lift?
I believe the lift is .444. I would think that the GT40P heads could handle that with no problem. I put a E303 in my 88 HO with the original 163,000 mile springs and it will still go 6500rpm. That cam is .498 lift.
Both motors have a factory roller cam so the springs will be sufficient(though just barely) for either cam. If you are going through the trouble of changing the springs use an aftermarket set with higher seat pressure and a greater spring rate. Stock seat pressure is only about 80-90 lbs with about 190-200lbs open, and this deminishes over time as the springs weaken and causes the valves to float at higher rpms(4500+).. which means a loss in power. The recommended springs for the Comp cams roller I just installed have 130lb seat pressure and nearly 300lbs open for example.
Why use a Mustang HO cam when there's probably a thousand newer, better cams available?
I was gonna mention something about that but the OP didn't mention what vehicle this was in so I figured I'd wait and see. As the Baron was indicating, while the HO cam and GT40 heads will produce more peak HP on the 5.0, that peaky powerband is not the greatest in a 4500lb truck.. makes the motor feel even weaker below 3000rpm. This is just an FYI in case you happen to be putting this motor in an F150 or Bronco.
I am putting this in a 66 2wd f100 in front of a zf trans. I am open to suggestions on the cam, but I am honestly surprised to hear that the mustang cam is a poor choice, seems like a mild cam. What would you recommend?
If curb weight on this is closer to 3500lbs then 3.55 to 3.73 gears will produce good results, it the weight of the vehicle that hampers street performance with a small V8. The HO cam is pretty mild as cams go, it produces a nice broad powerband on a stock EFI motor, but once you deviate from that combo of parts the powerband shifts. You didn't mention if this was going to be a carb or EFI motor and what intake you are using.
It is an efi motor, I will be using the explorer intake, and a mustang A9L ECU, dizzy, etc...
I understand how the powerband shift works, but this is where I get confused. OEM engineers spend a lot of time to put a good combo together. But on the explorer, why did they use these better flowing heads, throttle body, and intake, basically high(er) RPM stuff, and use a wimpy cam?
The way I am looking at this is, I am building a 2001 explorer 5.0 with a cam upgrade. Considering that my f100 probably weighs the same if not less than the explorer that the motor came out of.
I think I had better upgrade the springs in case a bigger cam will be installed!!
I would look into a TFS Stage 1 cam or an E303 cam and look into some port work for the heads and intake manifold. Those springs that are in there will be just fine for the stock cam, mustang cam or most other mild camshafts. Talk to the camshaft manufacturer to get their recommendations on valve train parts though...
__________________
Chris
1994 Mustang GT
1992 Explorer XLT
2000 Expedition EB
I understand how the powerband shift works, but this is where I get confused. OEM engineers spend a lot of time to put a good combo together. But on the explorer, why did they use these better flowing heads, throttle body, and intake, basically high(er) RPM stuff, and use a wimpy cam?
Considering the requirements they have to work within it's amazing we get a vehicle that moves.. they have to meet emissions targets while making the motors docile, quiet, smooth, powerful, and reliable. The Explorer cam is a mismatch to the GT40 top end for sure, especially if you look at the HP potential(300+), but the 5.0 truck intake is an even bigger mismatch considering the puny cam the early motors got. Who knows why this happens. The 5.0 is no TQ monster, it won't produce much more than 300 ft/lbs no matter what cam or intake you use, the only thing that will change is where in the powerband you get that much TQ. For maximum sub 4000rpm TQ you want the HO intake(all port matched) and a sub 260deg duration cam, the smaller runners will produce more intake velocity at lower rpms and as a result more TQ down low. If you are more concerned about making max HP above 4000rpm, then go with the the GT40 parts and select a 270+ duration cam to compliment what the motor will naturally do. It all comes back to how much air the motor can move, if you put these GT40 parts on a 5.8 they are actually a bit restrictive at higher rpms, because the bigger motor can move more air. See here for more info..
I would look into a TFS Stage 1 cam or an E303 cam and look into some port work for the heads and intake manifold. Those springs that are in there will be just fine for the stock cam, mustang cam or most other mild camshafts. Talk to the camshaft manufacturer to get their recommendations on valve train parts though...
I like my E303. With 70mm TB and MAF, along with the Explorer intake, it makes great power from about 2500 to 6000rpm. Nice lope at an idle as well.
If I were to step up the cam, what about the ECU? My previous thinking was with the explorer setup and HO cam, the A9L ECU and 19lb injectors would be OK. With a bigger cam do I need to do some ECU mods, and use 24lb injectors w/ the matching MAF sensor?
I wouldn't worry about matching injectors and MAF and instead plan on getting a dyno tune. They can adjust for all of that in the tune as well as making sure that you get the most out of the combo while knowing that it is safe and not going to let go.
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Chris
1994 Mustang GT
1992 Explorer XLT
2000 Expedition EB
No dyno yet. I still need a good set of heads. The old stock E7TE's are at their limit.
But so is my wallet for awhile. Our plant is closing soon and I'll be temperarily unemployed for a bit as of July 28 right now.
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