LayZ

Since the zz4 crate motor makes 350Hp with the fast burn heads. Is it possible to put them on the vette until i can afford AFR's?

vader86

yeah, they might not have the upwards potential of the AFRs but theyre still pretty good.

tommelton

Huh??? The stock ZZ4 head is NOT the FASTBURN head. The stock ZZ4 crate motor head is the late L98 Corvette head.

The FASTBURN head is basically an aluminum Vortec head, and requires the Vortec style intake. The ZZ4 head requires the non Vortec intake.

Tom Melton
82 CE
86 Z51 Coupe with ZZ4

LayZ

That clear'd that up. A guy had offered me the heads off a zz4 said that they were fastburn.

Marcho Polo

zz4 heads are like the 88-91 D port heads... right?

HWoods

the 385 horse zz4 version is alum vortec heads, I believe

gtsyellow

there's a bit of a mystery here, the 113 casting which i had on my car are exactly the same casting the zz4 has. however it's possible my heads were replaced as the last owner really overheated the engine. if someone else with a stock headed 1990-1991 is on, check your casting numbers under the valve cover mine are 10088113 this is also the zz4 casting. with a 3 angle valve job and the bowls cut, good valves like manley pro-flos and some porting you can make these heads really wake up. anyone who knows the basics of head porting and has some skills can get around 225-230cfm intake flow at .500 lift from this casting. TPIS gets about 250 cfm from theres with the larger valve and vastly more experence than the average engine builder.

tommelton

The ZZ4 crate motor uses essentially Vette D-port heads. GM has the Fastburn 385 that is based on the ZZ4 SHORTBLOCK and it has the Fastburn cylinder heads, which are as I stated above, are essentially aluminum vortec heads.

But, no matter what the Fastburn heads require a specific vortec style intake manifold, and will not work with factory, or OEM style replacement manifolds that are designed for the normal Vette heads.

Also, the initial post was about the heads on the 350hp ZZ4, not the 385hp Fastburn 385.

-Tom


[Modified by tommelton, 7:14 PM 7/18/2002]

Marcho Polo

The casting on my 1990 heads are the same as gtsyellow mentioned....

18carfan

ZZ4 heads are almost identical to the later D-port L98 heads if not.

If you do some comparisons with the Fastburn head, you'll find that they are very similar to an LT4 head - even more so than an iron Vortec head.

The only differences between a Fastburn 385 and a ZZ4 are the heads and intake. The intake being different mostly because of the .200" raised ports present on the Fastburn heads. A 30 HP increase out of the box for a pair of heads is fairly good. Also, GM is updating the Fastburn head as we speak and is claiming a 10% increase in flow. There is also a RamJet crate engine in the works rumored to make near 430 HP utilizing the Fastburn heads and Hot Cam. Also an all aluminum injected big-block and a 572 inch crate motor too. Hopefully next year will be exciting! -Jeff

MinnesotaWhite

Ask BobZZ4 on this board...his name says it all!

gtsyellow

did someone forget the 163cc intake runner compared to the 215cc runner on the fastburn? that's a HUGE difference. the exhaust ports are quite similar however. anyway if someone were to use the fastburn heads TPIS makes a miniram to fit it, TPI won't fit, well not without major work & welding, the scoggin doggy lower might but a 215cc runner is pretty big and i'd wonder about leaking. stock fastburn heads and a fairly stout cam kind of like the one in my sig or maybe even slighty larger and the miniram will make about 450hp on a 355ci engine at 10:5-1 compression. if someone were going to do a rebuild and miniram at the same time this would be a really really easy combo to bolt togeather.

LayZ

http://www.paceparts.com/product.asp?0=243&1=246&3=788
ok I'm confused even thou you guys have said a fastburn head is like a vortec why on this site does it say it uses conventional cooling and not for use on LT1, LT4 etc. I know that LT1 cooling is diffrent. So why not these heads on the L98?

18carfan

The Fastburn head is a derivative of the Vortec/LT4 head. The difference between LT1/4's being that is designed to be used with regular (old-style) coolant flow blocks like the L98. Now, the Vortec is NOT a reverse flow head - only the LT1/4 heads are reverse flow. Iron Vortec heads will work on a L98 blockk too along with the Fastburn but the intake requirements mentioned above still apply. -Jeff

LayZ

Ah i get it now, ok it's good to start off the day learning something.

opel

I'm in the process of changing the stock iron 85 heads to the iron Vortec heads. If the heads you were offered are fastburn they are the same as the Vortec you will need the SDPC intake. You can't beat the price of the Vortec $224 ea compleat or the fastburns for $545 ea compleat the one thing you have to remember is the intake $399(It's a direct bolt on for the L98).
But if you compare the fastburn and intake $1390 with the AFR's about $1500 you are better going with the AFR's.
Dave
:flag

65Z01

LayZ, the stock #113 castings used on the '88-'91 Vette flowed to ~350hp; pocket ported to over 400hp.

If you can get those at a good price you won't need the AFRs if staying with a 350/355cid block. Just have them worked a little before installation.