I already changed carb (edelbrock 650 cfm) and intake (edelbrock performer), so the car now runs without CPU help (I also changed headers and installed true duals).
I want to rise the CR, do you think those heads will make any difference? There will be some adjustments to make the heads fit on my engine? What cam do you suggest?

Thank you

 

What cc chamber heads do you have now, and what is the chamber size of the heads you want?

If you want higher compression and better flow, a set of Vortec heads would be a good choice. They are 64cc, and flow better than any other stock small block head.

Most salvage yards have them cheap as pull offs from trucks and SUVs, and they won't require much machine work.

The only problem is you have to have a Vortec specific intake manifold. Maybe sell the current one and get a Vortec manifold?

 

The heads you are talking about are the L98 or zz4 aluminum head. They are 58 cc chambers and will probably raise your compression to the 9.5-9.8 range. They will bolt on with no mods/adj but you will need center bolt valve covers. They say that self aligning rocker arms are needed but my roller tips have been doing fine on my very limited run time. As for a cam, these heads don't flow enough air to be on an engine set up for high rev power so stay with something just above a stock grind. I am running the comp xe268 but there certainly could be better cams for the L98's. I had the cam in the engine when the camel backs were on it so I left it in there when I switched heads.

The L98's do give up a small amount of hp at the top end, however their torque numbers are practically equal to the vortec. If you do the vortec you will need a new intake as Dboy said.

Basically they are a respectable light weight street head not a high rev high hp option.

 

Those 91 heads could be off a 305 w/ 59cc chambers. That would push your compression over the top.(race fuel)

 

hugie, the zz4 is only 10-1 with flat tops. If he keeps his dished pistons he will be no where near that.

I lifted this from another site it even lists the part numbers he may need.


SBC Corvette Aluminum Cylinder Head Assembly (This is also the ZZ4 350 HO Cylinder Head).
This aluminum cylinder head assembly for small-block Chevrolet V8s is ideal for street rods, fresh-water power boats, and high-performance applications. GM Performance Parts’ aluminum cylinder head assembly combines the benefits of light weight, advanced design, and an affordable price. This complete head assembly includes valves, chrome silicon heavy-duty valve springs, retainers, 3/8” screw-in rocker studs-everything an enthusiast wants in a high-performance cylinder head package!

GM Performance Parts aluminum cylinder head assemblies are based on brand new Corvette light alloy castings (P/N 10088113). The Corvette cylinder head’s advanced design features include D-shaped exhaust ports that enhance the flow of burned gases, high-velocity intake runners that provide crisp throttle response, and centrally located spark plugs that improve combustion efficiency. Valve seat inserts for 1.94” diameter intake valves and 1.50” exhausts are installed in the 58cc combustion chambers. Raised rocker cover rails with machined sealing surfaces virtually eliminate rocker cover gasket oil leaks.

This high-performance cylinder head assembly is used exclusively on High Output 5.7-liter small-block V8 engines. Unlike production Corvette cylinder heads, it is outfitted with special heavy-duty valve springs (see part number 12551483 for technical specifications(JIM: These are the same LT4 springs as the Hot Cam Kit). A pair of aluminum cylinder heads offers a weight savings of approximately 50 pounds over comparable cast iron cylinder heads. (A bare aluminum casting, less valves and springs, weighs 19 pounds, versus 44 pounds for a bare cast iron head). This reduction in total engine weight of 25 pounds each can improve handling, acceleration, and fuel economy.
Part Number ... Description.
12555269 ......... Stamped steel rocker cover.
10229162 ......... Corvette screw-in oil filter cap.
12342056 ......... Chrome screw-in oil cap with GM logo.
12338092 ........ .Valve cover hold-down bolts (8 required).
14094717 ......... Hold-down bolt washers (8 required).
14088793 ......... Hold-down bolt gaskets (8 required).
14088564 ......... Neoprene rocker cover gasket.
12557236 ......... Composition head gasket, .051” thick.
12495499 ......... Head Bolt Kit.
12495490 ......... Rocker Arm Kit.

Technical Notes: This casting does not have intake manifold heat riser or EGR passages. The exhaust port exits are approximately .100” higher than production cast iron heads; exhaust manifolds and aftermarket headers may require modification to maximize airflow. The spark plug holes are angled; check for adequate exhaust manifold or header clearance. Use 3/4” reach gasketed spark plugs with 5/8” hex heads (AC FR5LS), 904, or MR43LTS. In Rapid Fire use #8 plug. Both ends of the head are machined for alternator, power steering, and air conditioning compressor mounts. No pushrod guideplates; use rail type rocker arms P/N 10089648. This aluminum head assembly requires valve covers with central hold-down bolts and extra-long bolts with washers. A composition head gasket with stainless steel fire rings is recommended to prevent galvanic action between the head and a cast iron engine block. This head assembly is the same as P/N 10185087, except valve spring and retainer change.

These heads respond well to modest porting and a good valve job. The ZZ4 will get to an easy 378hp/412trq with just this mod. These heads do not like to ping at all, and they do not like over a 150 shot - that and the hypereutectic pistons. The intake port can get close to 180 in size after porting. The D-port exhaust means you have to check your headers and header gaskets to make sure everything lines up OK and that none of the exhaust ports are blocked in any way with everything attached and tight.
The Felpro Head Gasket with the pre-flattened steel fire ring works great and adds a little compression.

David Vizard talks this head extensively, as well as porting instructions and pictures, in his book "How to Build & Modify Chevrolet Small-Block V-8 Cylinder Heads (Powerpro Series)". Great book!

 

Thanks for your replys.
Yes, the y shoud be alluminium L98 or ZZ4 heads, and Yes, their combustion chamber is 58cc.
My problem is that I live in Italy, and trying to buy stuff heavy like heads overseas would cost the double of the price of the heads themselves...
I can get those heads complete with valve covers, all the stuff inside and cam for a really interesting price, that's why I was interested.
By the way, would you suggest to use the 91 cam or get new cam/lifters?

 

No advise on what cam to use? Will the stock 91 cam be fine for this setup?