Holley SysteMAX II

DFG 5OH

Active Member
Aug 28, 2004
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Louisville, KY
I was reading through my Summit, and saw the Holley SysteMAX II kit for the 5.0 Mustang. It looked, and sounded good, producing Horsepower: 350 @ 5750 RPM, Torque: 350 ft./lbs. @ 4000 RPM. I've never really heard anyone talk about this, and i know you'd need quite a bit more than the kit includes, the biggest thing being a beefier transmission. Would this kit be worth the money? I dont hear much about Holley products, so i dont know about their quality. Would this be a way to go, or just piece together AFRs, Eddy Intake, and a Custom Cam. Sounds cheap for the HP and Torque gains, i didnt think you could build your own combo for less than 2500, and push those numbers???

Help me out if i'm wrong
:shrug: :shrug:
 
Dyno numbers are misleading. I can guarantee you that those were engine dyno numbers because the camshaft that comes with that combo is garbage. 350 FWHP x 15% drivetrain loss = 297.5 RWHP. That's generous. They didn't say what kind of gas they were using or what kind of camshaft timing, either. Go figure. There is a reason.

With a custom cam, the 300 RWHP number can be elipsed quite easily and the car will be very streetable. Ed Curtis has a good grasp on the Holley heads because they are nothing more than a pre-CNC'd AFR head. He'd be the man to talk to.

Joe
 
I believe those combos have dynoed around 285-290rwhp...but peak numbers don't mean much...I would look into something like the TW packages...those seem to be putting up good reliable power and streetability...I'm sure they are both fine combos for the money...
 
Matt, my dad has the holley systemax II kit on his 91GT. Adding the kit, 30lb injectors, fuel pump, rockers, and 70mm t-body took him from a 13.6 at 98.9mph to a 12.6 at 107mph and this was with the "old original" holley cam which was CRAP, they have changed it since then. He then sent the heads and intake to Ed Curtis to be ported, installed a custom FTI cam, standard bore SRP pistons (for PTV clearance), 4.30 gears, and bogart D10 wheels. With these parts he ran a 11.95 at 115mph. He recently added to that a PA racing tubular K member, a arms, coil overs, and strange adjustable struts. His new best is a 11.8 at 117mph.

Rick91GT also ran this kit for a while in his 91GT and he knows a lot about the kit as well. I do think its a good kit, the heads are not the best out there but they have a 2.02" valve (that clears the stock pistons) and flow pretty well with some porting. There were a few times that we were going to throw in the towel and swap the heads for something else, but after working on the combo and getting the bugs worked out, its flat out hauling ass. That 11.8 was with a 1.7 60'! We haven't weighed the car since doing the front suspension, but it weighed 3350lbs with dad in it when it went 11.9 at 115mph, and the front end only dropped ~60lbs MAX, so its still no lightweight.
 
No problem! BTW- we got the kit at advanced auto. :LOL: Seriously! At the time it was the same price as everyone else and my dad felt better ordering from someone "local" in case anything went wrong. We didn't have to pay shipping, but we did have to pay tax on it. I know Ed was pretty impressed with the heads after he got down with them.