Thread: ZZ383/425 Hp GM Performance

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Just found this forum,looks good.I just picked up a crate motor from GM and wondering if any-one has any expierence with them?Its a ZZ383/425 HP c/with aluminum heads.Would also like to replace the plastic timing chain cover but am having trouble sourcing a polished aluminum one,if you know who produces them would be great.....thanks in advance

This is what you want: http://store.summitracing.com/partde...7&autoview=sku

You'll have to polish it yourself, but it is the only one that comes with a cam button for roller cams built in and isn't too unreasonable in price. Oh, and I do suggest a bigger cam while you have the cover off. GM likes to undercam their motors.

thanks for that, will try to get the cam specs on this thread

Well, I take that back about the cam. Looks like they were pretty generous, especially with the lift.

just in the process of figuring out rear gears with a beefed up 700r4 trans and 31.5" tall tires..........looks like 4:56 any thoughts

You will need at least the 4.56 gears. With the overdrive, tall tires, and 4.56 gears, you'll be burning only 2200 rpm at 65mph which is just right for a highway cruiser.

FWIW, I run 3.89:1 gears in my '32 and would not want to go any deeper with te 700R4's low first gear. I thought about 4.11's but I'm glad I went with what I did. The 383 I have with a CompCams 280 Magnum cam likes that gear choice.

thanks guys for the input,exactly what I`m after,feedback before I shell out a bunch of coin.Lynn how tall are your tires?Thanks again.

33delivery, what is your idea for the car? The 700r4 has a 3.08:1 1st gear, you are gonna ROAST the hides at every light with a 31.5 inch tire. Besides the concept of overdrive is to lower engine RPM on the freeway. 2200 revs at 65 is quite a bit these days. I realize it's a hot rod with a hot motor. Just some perspective, my wifes car a stock 95z-28, 275 horse with a t-56 trans. The motor runs about 1700 at 65, just loping along. I'm not exactly sure but, I believe a 3.50 gear with a 30 inch tire and a 3.08 1st gear wil be like a 4.11 overall gear. Anyway I just wanted to give you a little more info. Oh yeah, I didn't use any calculators for that just off the cuff from building my car. I'm runnning a blown 406 w/700r4 w/29.5 inch tire and 3.00 & 3.50 rear gears. I like the 3.50's the best, but I like low rev's on the hiway! Good Luck...

thanks blwn31.I guess what I want is everything,will be attending some of the bigger rod runs in the lower 48 "Good Guys + NSRA" closet one being 1200 mile round trip,we really enjoy the cruising at these events.Will be travelling in groups to and from so want to make sure I`m not last.There is a dragstrip not far from here and they always have "run what ya brung" and also street rod drags so don`t want to be last there either.and lastly this car is a "phantom",the engine compartment will be pure "bling"and did I mention its also got "fatties"So this is why I joined this forum to get the knowledge and expierence from you and the rest of the participants of this forum.I need to learn to post a pic of the rendering I have....help....thanks fer now

check out Sallee chevrolet in miltonfreewater orygun.they sell the same engine and have anything ya need for it.

thanks fer that jd.just heard from friends in British Columbia forest fire creeping in around his house and rod shop.They need rain in BC, Prairies have had enough go figure...............33

Originally posted by 33delivery
thanks guys for the input,exactly what I`m after,feedback before I shell out a bunch of coin.Lynn how tall are your tires?Thanks again.

I'm running P285 70R 15's. They are spec'd at 30.5 inches in diameter.