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ZZ6 or SP383

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  • SP383

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cubic inches please, more cubic inches please.
 
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Discussion Starter #4
Couple links to explore the details of both of those would help a lot.
ZZ6



SP383


 

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cubic inches please, more cubic inches please.
Bigger is better

Originally published in Sports Car Illustrated in February 1957. "There's no substitute for cubic inches."

 

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Depends on the application.
GM always puts some goofy parts in their engine. Forged crank, hypereutectic pistons and PM rods? ***? Personally, I don't like the powdered metal con rods and hypereutectic pistons. Im not a super-fan of externally balanced engines. When we did my dads 383; we decided to go with a more basic cast crank, 6" forged rods and SRP forged pistons. We were able to balance it internally. He ended up around the same price as the SP383, having it done locally.

If its just a mild cruiser? The 383 hands down. It'll be so comfortable to drive in the 1500-4500 range, and make so much torque down there...you'll never consider a NA 350 again.
I highly recommend the new AVS2 annular booster Edelbrock for a lot of street/mild strip apps.

To be honest, my dads old-school -462 heads/260H hft cam/600cfm Edelbrock/Performer Airgap (not RPM) 331 got worse gas mileage than his 383 does. The 383 runs cooler, makes an easy 100hp/like amount of torque more and is super mellow to drive. He was afraid when I was going through all the options, because to his mind, 450hp is a "race" engine and cams with durations in the upper 220s are high strung. You can hide a lot of duration in 388ci. Its a Jones cam and around 224/228 duration and .510 lift, similar to the SP383 cam, and his heads are Pro-Filer All Americans.
 

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More weirdness in the ZZ6:
The cam is listed as a 208/221 deg dur at .050" Thats a LOT of split for a modern head; not so for the 58cc L98 vette heads the cam was originally paired with.
Furthering the weirdy factor is a SINGLE plane intake and a spec for a 770cfm Holley. to make 400 horse. Which means most of that 400hp is where most of us would never see it, and ripping the singleplane off for a basic RPM dualplane-type design would probably net some noticeable gains on the street.
 

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Check out BluePrint engines. Save yourself a couple thousand. They make good power, have a long warranty and are pre run before being shipped.
 

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For what you're getting, I think the GM engines are very overpriced. I'd grab a shortblock from them maybe...and put a better cam and better heads on it. Also, as noted above, the ZZ6 with the single plane and a pretty mild cam is just stupid. You're basically wasting $250 on that single plane intake. To make matters worse, GM also puts on an .051 head gasket killing the quench and compression on any head.

Long story short, I wouldn't spend a dime on a ZZ6. The 383 isn't a bad motor.
 

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I agree with Bill. The SP383 is about $7K and comes with a single plane intake which isn't the best bet on the street, even on a 383. That's probably $250 to $300 down the drain off the bat. It also has a dated cam and so-so heads.

Here's what I'd do instead.

Blueprint Engines shortblock with better cam (not as big of a duration split, but still pretty mild for a 383) $4K

AFR 195 Cylinder heads with .028 head gaskets, ARP bolts, pushrods, and roller rockers - $2300(ish)

Performer RPM (or similar) dual plane intake with plenum notch - $250, give or take

For $500 less (minus a little elbow grease bolting everything together) you have a motor that would probably make 25-30 more HP/torque, maybe more

I won't get into the LS stuff, but it's gotten to the point where an LS crate motor is comparable in price to the SBC crate motors and frankly, they're superior in almost every way. If all you want is 400-450HP, it's gonna be tough to beat an LS3.


This thing is what, $500 more than the SP383? Of course, you need supporting components, but it's kinda disgusting to be honest.

I put a 421 Dart SBC motor in my '56 a few years back. If I could do it over, I would've put a modified LS3 in it.
 

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Discussion Starter #14
For those of you not a fan of the ZZ6 or SP383, two questions:

1) Aren't the BluePrint heads no-name brand from China?

2) What do you think of the Shafiroff 350?

 

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For those of you not a fan of the ZZ6 or SP383, two questions:

1) Aren't the BluePrint heads no-name brand from China?

2) What do you think of the Shafiroff 350?

Blueprint heads are very likely off-shore castings yes.

That Shafiroff motor is a little spendy, but it's still cheaper than a ZZ6, likely has a better cam, has comparable heads, and has an intake better matched to the motor than the ZZ6. I wish they posted the cam specs...to make 415HP on a 350 it probably has a cam in the mid/high 220's, maybe even into the 230 range.
 

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“2) What do you think of the Shafiroff 350?”

another weakling,
383 offers so much more torque (with very little loss of quick revving ability) allowing more cam. Street 383’s regularly produce 500 HP

Almost same price to build either.
 

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Discussion Starter #17
“2) What do you think of the Shafiroff 350?”

another weakling,
383 offers so much more torque (with very little loss of quick revving ability) allowing more cam. Street 383’s regularly produce 500 HP

Almost same price to build either.
What do you have in yours?

What do you recommend?
 

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“2) What do you think of the Shafiroff 350?”

another weakling,
383 offers so much more torque (with very little loss of quick revving ability) allowing more cam. Street 383’s regularly produce 500 HP

Almost same price to build either.
A 383 with 500 HP is probably going to need a cam into the 240's as well as a single plane intake, and possibly a spacer. I doubt it'd be very street friendly, but yes, it's certainly possible. Building one with an aim at 450 or so would probably make it much more friendly on the street.
 

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Agree with Hutchenc, you will definitely loose some street friendly manners with NA 383/ true 500 hp combo.
 
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