Same old questions ... what heads to use.

[dk1977]

I have a '77 L-48. The moror was rebuilt: two owners ago and I have no idea what was done. It runs good, just "NOT ENOUGH POWER". This winter I will pull the original heads and check piston type (flat or dished) Based on that finding, I am considering the Vortec steel or the fastburn alum. The fastburns have 2.02 & 1.60 valves. The iron have the smaller valves. This is a street car, driven sparingly, but I want more power. It has a 3.55 gear and 350 auto with a B&M holeshot 2400 rpm, dynomax headers and true duals. Eldbrock performer and eldb 650 cfm carb. Now it will only stalll about 1900. A cam change will happen with the heads, another dilema. Any thoughts on the iron vs. aluminum? What cam would work best (need semi lopy idle to sound coolbut something easy on the valve train).
Any ideas ?
DK

 

[Sensei]

Try a set of Dart Iron Eagle 180 runner heads, part # 10221111. These are straight plug heads with 72cc chambers, so you can use them with pump gas. You can pick up a set of these heads new on ebay for under $800 delivered. Also a Cam Comp xe262h-10 or xe268h-10 camshaft would be a good choice. This combo should give you an efficient street machine with plenty of power without throwing alot of money away. God bless

 

[Jack]

I have a '77 L-48. The moror was rebuilt: two owners ago and I have no idea what was done. It runs good, just "NOT ENOUGH POWER". This winter I will pull the original heads and check piston type (flat or dished) Any ideas ?
DK

First ... find out piston type & likely dome volume ... measure diameter & depth of any dish ... note any numbers stamped into piston tops ... with that you can figure out dome volume & calculate CR. Also measure how far "down in hole" or if "zero deck". With that knowledge, you can choose head & compression ratio. Then you choose cam profile.

As you probably already know ... L48 came w/ dished 4vr ... about -10cc dv.

Both Flat 4vr & 2vr typically about -5cc dv.

Lotsa decent new Aluminum 64cc chamber heads for ~$750-$1000/pr COMPLETE. Most of the heads made today have the fastburn chamber ... no matter who makes em ... no matter what intake bolt pattern.

If block has NOT been decked ... Typical +30 flattop 355 w/64cc heads about 9.7:1 CR. Same w/typical dish about 8.9:1 CR.

Decent good used GM L98 vette Aluminum heads go for ~$350-$700/pr COMPLETE. Same head as on plain GMPP ZZ4. Chambers are NOT true fastburn but are small 58cc.

If block has NOT been decked ... Typical +30 flattop 355 w/58cc heads about 10.4:1 CR. Same w/typical dish about 9.5:1 CR.

Pull a head ... read & measure ... go from there. G'Luck.
JACK:gap

 

[curtis]

Check out the new Vortec Bow Tie heads here. http://superchevy.com/technical/engines_drivetrain/cams_heads_valvetrain/0511sc_vortec/ and here is a great page about the older vortecs and parts etc http://www.sallee-chevrolet.com/frame.html?/Cylinder_Heads/Vortec.html and here is a real tough cheap engine http://superchevy.com/tech/0312sc_dm15/