merim123

Ok, I love these heads posts every time we get one. It's an amazing learning experience. Thought I'd share this since I just found it on the web.

From their website.....Take full advantage of this high-flow "CNC" ported cylinder head. The Pace "CNC" cylinder head starts out as a brand new LT4 assembly and is sent off to ET Performance in MI, where the intake ports as well as the combustion chambers are "CNC" machined for optimum flow potential resulting higher horsepower. These heads are complete with valves, springs, and studs. Check out out the flow numbers below:

***AS CAST From GM LT-4 Head***
Valve Dia.: 2.000" 1.550"
Lift Intake Exhaust
0.100 68.5 54.2
0.200 130.4 101.6
0.300 181.0 133.5
0.400 217.1 155.2
0.500 244.0 166.3
0.550 234.0 169.4
0.600 235.0 172.0


***12363287ET CNC Ported LT-4***
Valve Dia.: 2.000" 1.550"
Lift Intake Exhaust
0.100 70.6 46.9
0.200 134.1 96.8
0.300 192.0 132.2
0.400 237.6 165.5
0.500 268.5 184.6
0.550 273.8 189.8
0.600 277.5 195.3

Ai

I've seen those on pace parts for $2200, and I'd beinterested to see what they actually flow for sure. If the #'s are accurate, then they're on par with a fair worked LT4 head - not good, but considering some of the garbage people sell, definitely not bad.

The only bad thing is that they come with garbage stock components, so if you want to buy them and run them, plan on throwing that stuff in the trash and spending $ on decent components

Someone want to buy a set and send them in to be checked out? I'm curious


-Phil

merim123

Phil, I still plan on buying your stuff, just a timing thing...

I'm just curious how good/bad this is overall and you've answered that.

Ai

I think thats a pretty good deal, but a well ported LT1 head will outdo those numbers.

I'd definitely like to see what they do though, those arent bad #'s. Of course people have to keep in mind.. flow is only part of it. If I had a budget to adhere to, and could either have great flow with junk parts, or okay flow with great parts.. I'd pick the latter every time. Valvetrain parts are the most critical, yet fragile parts... Cheaping out in that respect can easily smoke a shortblock

Soma07

Hey Phil,

Just curious, what you and your crew think of the factory LT4 valves? Flow wise are they comparable to a Manley or Ferra?

I was thinking since they're the 'right' size (2.00/1.56) and hollow they could make a nice, lightweight valvetrain in combination with some Ti retainers.

Thanks!

Ai

FWIW, I toss those as well...

You can use them, they'll work for most people. If you're out to get what you can out of the casting though, whoever does your stuff will likely tell you to run something else .

-Phil

Soma07

Ok, so they suck

Too bad, I thought I may have been on to something Oh well...

Thanks again!

Ai

For alot of people, they arent the limiting factor, so it just depends on what you're trying to do

NightTrain66

The #'s do look descent and from the increase they probably did not take out ALOT of cc's either. The LT4 STARTS OUT bigger than a LT1 with a back-hoe ran through it. Like Phil said, a LT1 head would work better for most peoples needs. IMO I would either use a stock LT1 and if ya need more CFM and can handle the extra runner volume I would jump to some AFR's.

The flow #'s do look realistic, They are not claiming "81" cfm at .100 lift or "152" cfm at .200 lift like some people. They are probably gonna flow close to what they say.

Phil mentioned the parts that come on them are junk and probably are. Ya might check with them and see what stuf is on them but it is probably either factory GM or private label stuff.


NightTrain66