Considering upgrading my zz4's heads and cam

[CDaniel525]

I put this in the C3 Perf section but didnt get many replies... figure'd id try here

I am considering swapping out my stock ZZ4 heads for some AFRs and the HOTcam that I already installed for a Compcam...
I posted this setup a few years back, but no one ever seemed interested in it... its basically a stock zz4 bottom end with the AFRs and Compcam... I already have the single plane intake, 750 carb, and good exhaust...
I can see doing this setup for under $2500 myself. Doesnt seem bad to achieve 500+Hp IMO.
I have some questions tho as im no expert on building up a motor.

The stock ZZ4 heads are 58cc chambers, but the smallest you can get in a AFR is 65cc. I am presuming I would need to have the heads milled to retain my 10:1 compression ration? or how close would the ratio be running the 65cc and how much HP/TQ would i lose by not matching the 58cc? If I decide to mill the heads, is this something AFR can do from the factory and tack on the price? Or am I better off buying them from summit and having a shop mill them down?

This setup makes some serious power above 6000RPM and AFR recommends their higher rating springs and a "Hydra Rev Kit" IS this something I should definitely get? if so there are 2 different types, ones for factory lifters and one for aftermarket... im guessing the zz4s would be factory??

Here are the cam specs...
Part Number 08-444-8
Engine -Present Chevrolet
305ci-350ci
8cyl.
Grind Number CS XR300HR-10
Description
Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.562 0.58
Duration At 0.006 Tappet Lift 300 306
Valve Timing At 0.006
Open Close
Intake 44 76
Exhaust 87 39

These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 248 254
Lobe Lift 0.375 0.387

Lobe Separation 110


Lastly, is this somethign that I would be able to do on my own? Or have to have a shop do... I am definitely mechanically advanced... already did the HOTCAM, but with help of my father. Changed the intake a few times, but like I said am capable of working on things... if I do it, whats involved in doing the heads? im guessing its fairly simple bolting and unbolting them, and dropping in the other parts?? Also, when I did the cam last time, I dont remember using cam timing wheel... is it completely necessary.. if not, how should I approach that install??

Thanks in advance with all the questions!
Chris



Parts list
1 - Heads $~1400-1500 + milling?
2 - Springs - $108
3 - Hydra Rev Kit - $240
4 - Cam - $256

Im running a Tremec TKO 3.27:1 first gear trans, 3.55 gears, and use the car mostly for racing/hard street driving. Im thinking about 500HP will get me into the 11s Nat. Asp. if not close. Im running 12.8 @ 107 all day long with ~400HP

Combo 102 is a GM ZZ4 350 cu. in. engine with AFR 195 heads and a Comp Cams hydraulic roller cam. With an 850 carb and 1 3/4 in. headers, this engine produces 506 HP and 436 ft-lbs of torque. This engine shows what that adequate induction and exhaust systems are imperative for more power. 3 in. mufflers could have helped a bit, though.

Displacement: 350 cu. in.
Carburetor: Demon 850
Heads: Air Flow Research 195, with 2.02/1.60 in. valves
Intake: Edelbrock Victor Jr.
Camshaft: Comp Cams hydraulic roller, with 0.562/0.580 in. of lift and 248/254° of duration @ 0.050 in. of lift.
Exhaust: Hooker 1 3/4 in. headers and 2 1/2 in. Flowmaster mufflers
Pistons: GM high-silicon aluminum
Rods: GM
Crank: GM forged
Ignition: MSD 6AL
Comp. Ratio: 10:1

MAX HP: 506 @ 6500
MAX Torque: 436 @ 5500

[Cris]

Chris:

You didn't really state what you are building the motor for. Street with occasional strip use? Strip with occasional street use? The cam you listed is a HUGE cam for a 350, and will require high RPM's to come alive. Probably higher than a hydraulic set up is really intended for. You need to plan on this motor spinning above 7000 RPM to take advantage of the cam. It will not be a street friendly cam. I would also be a little leary of running a ZZ4 lower end much above 7000.

You also didn't state which AFR heads. I am assuming you are looking at the 195 Eliminators. They would probably flow well enough to get you to 500 HP with the appropriate cam.

I do not know the details of the ZZ4 pistons and deck height, but figure going to 65 cc's on the heads will drop your compression from 10:1 to around 9.3:1. I would recommend you download one of the many compression ratio calculators on the web to really flush this out. AFR will mill the heads for a nominal fee. Check with them about your combo.

You might also want to bend the ear of a (reliable) engine builder about your combo. You'll be money ahead.

Regards, Cris

[CDaniel525]

Thanks for the reply Cris...

The car is going to be used mostly for strip plus some occassional spirited street runs...
i was leaning torwards the AFR 195s.. im not too sure on the new Eliminator heads... havent heard much about them?? Any details? Ill have to check their site.


I found an online compression calculator and running the AFR 65cc heads with a .021 head gasket will have me at 9.755:1 I know they have some .013 head gaskets, but dunno if there is any risk running that small?? And how much power could I be losing from .25:1 compression. Or i could have the heads milled and then there are endless possibilities!


Everyone seems to think that cam is just way too high of a RPM range tho... so im beginning to wonder what kind of power I can make with those AFR 195s and the HOTCAM i have in there now with the 1.6 rockers.. .525/.525 lift and 218/228 duration at .050

If I can make over 450-460HP by just adding those heads I might go for it, and ill know that the heads are good for over 500HP if I can find a cam good enough for the same. Stock ZZ4 heads just arent cutting it IMO

[Cris]

Chris:

AFR has the results of a 383 with the Eliminator 195's on their website. A few of the car rags have also dynoed the heads. Joe Sherman built a 600+ HP 383, but it had a pretty wild cam in it.

You do not want to just change head gasket thickness without looking at things like piston to head and valve to piston clearances. Quench is also something you want to control. (Quench is basically the piston to head clearance at the flat portion of the piston.) As you said, there are endless possibilities, but that also means endless potential problems.

You could also talk to a good head porter and get his opinion on massaging your ZZ4 heads. It might be the simplest, most cost effective solution for you.

[Deakins]

If you drag the car a lot and it sounds like you do the compcam will be just fine. With a single plane intake in a manually shifted car you will want to pull a lot of rpm to be quick and 250's duration at 50 is not that large in the performance world. That cam will pull well up to about 6000-6500 and at that point you will begin to run out of cylinder head and cam. For what you are looking to spend that will be your best bang for the buck. If you want to do the build yourself have AFR mill the heads to the desired combustion chamber volume. Then contact GM and get the specs on the ZZ4 bottom end; stroke, rod length, pin height, deck height, etc, just to be sure. Once you get some numbers you can mathematically figure out what you are working with. Now how much clearance you want to build into the engine is up to you and that will tell you how thick the head gasket needs to be in order to obtain that clearance with what you have. Don't let any of the street oriented guys talk you into a smaller cam; the 110 degrees of lob separation will help with the idle and it's not like it wouldn't idle with a 107 ls anyway. If you have any questions feel free to pm me or post them here; hope this helps.