Thread: Aftermarket Head Options?

Good for the money, but you'll pay a premium! What's your plan? XPZ is upper end, so you're right to do it right, will benefit most from Stage3 or better heads. Flow is flow... Either ZZP or Intense. I like Intense Racing better, that's just an opinion but not based on performance cause I've never had ZZP heads.

ZZP XPZ:
217/225 .352/.333 116 N/A

Old info, but good to know anyways:
ZZP's Comp Cam XPZ grind:
1. Scott Kleis w/ 425WHP (I/C, G5 m-90, ZZP Alum Heads, 9:5:1) [STD]
2. Fred Cakanic w/ 421WHP (I/C, G5 m-90, ZZP S3 Heads, 9.5:1) [STD]
3. Zooomer w/ 413WHP (I/C, G5 m-90, ZZP S4 Heads, 9.5:1) [STD]
4. ALancour w/ 400WHP (I/C, G5 m-90, ZZP Alum Heads 10:1) [SAE / Mustang Dyno]
5. House w/ 393WHP (non-I/C, G5 m-90, ZZP S4 Alum Heads, 1.7 rockers)

I found those lists to leave some pertinent information out, like exhaust size, etc.

Anyways, I go for as much as the pocket can tolerate... Lol
Don't forget to save some scratch for the Trans too ; )

You will be interested in a turbo when you can save thousands from your 5k budget and spank m90's with oem heads.

Qwik ported oem heads on the Turbo Regal. 608 whp 570tq at 18psi.
Broke the transmission for the 11th time when we hit 26psi.
Juuuust sayin....

$5k... I'd go Whipple if you are set on staying SC
: )

but you'll definitely need some Trans investment no matter what and as mentioned above, these aren't bulletproof at all as you probably already know.

Port the stockers and don't bother wasting money on vendor head work.

Also wasting $5k on a 1500 dollar car is comical, too. EVEN more so on a blower setup that'll do 400WHP~ on probably it's best day.

DIY heads are definitely doable, with Youtube today, there's not a thing you can't see, learn. So if you have some time and space, you can port, polish you heads and save a bundle. But that wasn't the question... On that note...

Honestly, unless you're tracking the car and looking to eeeeek out every last drop of HP, the heads aren't worth it. Is why I said you'll pay a premium. Will the Vendor Heads flow better than DIY, of course. Enough to justify the premium $, not so sure. You can buy used, but be wary of the seller... Have the heads checked, they are prone to cracking but usually even when cracked, don't effect much performance wise. Biggest benefit is getting rid of casting defects that GM doesn't bother to do. Then polish all the runners...

: )

it honestly isn't worth it over a good teardown and cleaning and hitting the casting to machined area's of the intake and exhaust port.

our engies rotating assembly geometry is optimized for low/midrange Tq. and trying to move the power up top isn't helping you much without some serious manifold pressure to overcome the poor cylinder filling over 5000rpm

to put things in perspective. a local had a full tilt stock cam l67 engine (1.9 rockers/IC,e85,headers 2.8) and did 311 at the wheels at 11psi

a local I put a used 54mm kit on his 97 l36 TurBonnie, bone stock to the 4t60e the same kit with a s1x cam on the old car made nearly 450 at the wheels at 16psi, at 10psi it put down 380.

Tq to melt the tires at any speed, enough that its set at just 7 psi for the last 3 years without any reliability issues