69L71

I have a chance to pick up a zz4 with fast burn heads and LT4 HOT cam kit. The motor is used and has had a few rough miles, but its NOT blown up. If I get it, I fully intend to pull it down and give it a new set of rings and bearings. No sense in taking the risk of blowing something later. The alternative is to build up an inexpensive 383 or the 400 I have in my basement.

The car I need this for is a 69 convertible. It currently has an M21 and 370 rear. This is nice for the ZZ4/HOT, but I could make a gear swap to take advantage of the torque of the 383 or 400.

Thoughts?

robzr

I say build the 406 to rev 6500, that'll outrev the ZZ4 and make tons more torque across the board. What fun with the 3.70s!

Rob

Shark Racer

Build up a 383 out of the ZZ4. The roller lifters on the ZZ4 will give you more torque, and if you decide to go solid roller... well...
Warp 10 is possible. :)
-Steve

The Money Pit

I've built a ton of 350's and finally went 406 this time. No regrets. The torque will put a grin on your face you'll have to pry off.
Be reasonable on the cam. For the street I find I run between 2500 and 3500 rpms almost all the time,so I chose my cam to peak torque at 4000.
Don't worry about trying to hit 6500 on the street. If you can hook off the line,second will trash the trans or rear,or both for sure. Just a matter of time. The 406 you can drive like grandma,and when you need umph,just tap the gas,and it's there.

Fevre

Stroke that ZZ4. You will get about 390 cubes if you bore it .30 over. Of course the zz4 has a forged crank so you could just go 355 with 6 inch rods and get a high rev monster. Choices choices......

69L71

Its two different philosophies I’m looking at here:

The ZZ4/Hot is already there, and is complete from oil pan to intake. It just needs a carb, distributor, and starter to go. It even has a 4-speed flywheel. The ZZ4/Hot is a revver already. It’s the same motor GM sold as the ZZ430. It makes 430 HP @ 6000 RPM and 430 lb-ft at 4500. The nodular crank, PM rods, 4-bolt block, and decent factory balance should be fine to 6500 although I don’t expect to be there all that much. I can get it for close to $1500 less than a new base ZZ4.

To build a 383 or 400 to rev requires more than basic parts. Instead I’d build one or the other for good, strong torque at lower revs. My 400 is a 2-bolt (good) block with a standard cast crank. I can get a decent set of 5.7 rods without spending a fortune but I’m not gonna deal with the shorties it came with. 383s are a little easier since the donor block will already have 5.7 rods. Still, decent breathing on a stroker means better heads. Vortecs are usually a great choice but with a 400 they need substantial dishes to keep compression in line. So far the only decent dished pistons I’ve found go 10:1 with 64 cc chambers (ala Vortec). The alternative is to go aluminum. TFS heads are a great deal for the money but will still wind up being a good $1000 when all is said and done. 383s have more choices, but again, I don’t have a donor motor to start with. Then of course there’s the flywheel, and intake issues….

Regarding the 383, I’m really kinda leery about the offshore stroker cranks. I’m sure they’re fine, but the cheaper ones have shown they can be a challenge to balance. The good offshore and USA cranks are pricey. GM wants $1259 for the 3.8” crank they use in the HT383 crate motor. This is another reason to stay with the low-rev concept and stay with the cheaper cranks. To balance the driveline out I’d probably swap the M21/3.70s for an M20/3.36 or 3.08 and have tons of fun and a relaxed cruise. Of course the drivetrain swap is a pricey one too….

When all is said and done, there's no question that even a non-screamer performance 400 or 383 is gonna cost more than the used ZZ4/HOT. The ZZ is a screamer in the revs and OK in the mid-range. It should work OK with the 3.70s. The bigger motors can’t be built to rev in any sort of budget so its means going the other way. Building the ZZ4/HOT into a 383 down the road is an interesting possibility. Not one I’d consider right now though because I’d want a damn nice crank to do it right and that's not in the budget.

Also note that I already have a 427/435 4.11 coupe. I have it when I want max performance. I'd like the vert to be an all-around fun sports car with excellent power and handling. The low-rev cruiser idea is attractive to offset the coupe, but there's also something about the sound of a hopped-up small block reving its guts out.



[Modified by 69L71, 3:43 PM 7/10/2002]

VetteNut72

Quote:
______
I say build the 406 to rev 6500, that'll outrev the ZZ4 and make tons more torque across the board. What fun with the 3.70s!
______

I am running a ZZ4 with HOT cam, 1.6 rockers, 3.70 gears, p/p edelbrock heads and ProFlo EFI. The power and torque is awesome. I have the rev limiter set to 6500 and bang up against it almost before I can shift out of first gear. A 406 would be even better but will cost you more. I ran my ZZ4 stock for 2 years before I modified it and was happy until I got used to it. Personally, if I was to go larger in displacement it would be my choice to build a 420-440ci small block. If you are going to spend the money to go 406 then why not take it a little further.

I guess that the moral to the story is whatever you have you will get used to it and eventually want more.

Fevre

Just doubled checked and the zz4 has a forged crank.

Tominator

If I was in your shoes I'd build a 427 sb :cheers:

69L71

Show me how to build a good reliable 427 SB for $2400 and I'm all over it!

Right now the decision is academic. The ZZ4/HOT cam/Fast burn is in the back of my pickup truck. It also came with a brand new GM 4-speed flywheel and a performer RPM airgap manifold. I also confirmed that the motor has less that 1500 miles! Not bad for $2400

robzr

It sounds like you got a really good deal. I think you'll love the motor, a lot of guys with ZZ4s on here have nothing but good things to say about them.

Rob

Tominator

Looks like that zz4 is going to be a good motor for you, sounds like you got a good bargin.

Wish I was closer would so I could come over and watch with this project.

69L71

You can watch me from right here on the forum, Tominator. I'll have updates and links to pics posted in my sig line. But I must confess I probably won't be doing too much on this car or this motor until the wintertime or next spring. I need to get the 69 Tri-power coupe finished first.

BTW, the motor was far more impressive than I'd imagined. GM really pulled out all the stops with this baby. The 1.6 roller rockers are just sweet looking!