73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: BULLDOG on May 11, 2010, 08:05:15 AM
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I have an oportunity to buy some used zz4 heads and put on my 350.
Here would be the combo 350 short block,zz4 heads,edlebrock rpm performer,comp cams 268 cam with 1.6 roller rockers,1 5/8 headers with true duals.
What do you all think about the zz4 heads and this combo in a 1983 K20
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This is what I think I know: ZZ4 heads are factory C4 corvette TPI heads. They are not huge on peak flow, but have excellent swirl and very respectable low lift flow. If they can support over 355 hp with the mild cam they use in the ZZ4, I don't see why they can't support 400 hp with a better cam. One thing to keep in mind is they don't have a ton of deck thickness so any decking should be limited to just what is needed to get a flat smooth surface.
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^ Does that mean they are the same as the L98 Vette heads? I thought those came on TPI Vettes.
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ZZ4 is an alum head with the "fast burn" 62cc chambers 1.94/1.50 valves, LT 4 springs. 210cc intake runner. D shaped exhaust ports. these heads and a .475/.510 lift cam will make 385HP.
Good heads will work good with your compo
Steve
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http://www.summitracing.com/parts/NAL-12556463
I have looked around the net and these heads hav ea 165 intake port and a mild cam might make good torque down low in the rpm range.
Best part about these heads is I can get them for 300.00
I
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The ZZ4 heads have 58CC combustion chambers. You might want to be careful if you are wanting to run pump gas. Depending on what pistons, deck height and cam selection you may be pushing it.
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So how will 375 to 400 hp and 400ish torque effect a sm 465
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Since these are for 86-91 vettes, would they bolt right up to a TBI manifold from '87?
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How many bolt holes dows the tpi manifold have
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^ Does that mean they are the same as the L98 Vette heads? I thought those came on TPI Vettes.
Yes and Yes.
ZZ4 is an alum head with the "fast burn" 62cc chambers 1.94/1.50 valves, LT 4 springs. 210cc intake runner. D shaped exhaust ports. these heads and a .475/.510 lift cam will make 385HP.
Good heads will work good with your compo
This is incorrect, with the exception of the valve sizes, what you are describing is the "fast burn" head.
Since these are for 86-91 vettes, would they bolt right up to a TBI manifold from '87?
No, they have traditional SBC intake bolt arrangement (6 on each side, all at the same angle).
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I have seen 750+ horsepower on sm465 with very little problems.
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My bad summit has the ZZ4 in 355 and 385HP fast burn? that ain't right. the 355Hp is the ZZ4
1.94/1.50 163 cc intake runners. 58cc chambers, D shaped exhaust, same as L-98 vette, bolt pattern 1955-86, center bolt valve covers.
http://www.summitracing.com/parts/NAL-24502609/