As in sig. The center bolts were from an '87 LB9. I ground the perimeter bolt bosses down per instructions while the heads were disassembled. When I went to put the engine together, the rail inside the gasket on the covers would not fit inside the rails on the heads. The outside width of the cover rails is 4-3/8", and the inside width of the head rails is 4-1/4". That 1/8" makes a big difference.

I had to go back to the perimeter covers, and the lack of full bosses caused stud and gasket sealing problems. Still working that out, hate having to goop silicone on things to get them to seal.

I emailed World expressing my disappointment. Their response was that they have a couple of factory center bolt covers that they use as check tools, and that this comes up every couple of months. They said feedback they've received indicated later truck covers have the narrower rail. Gee, thanks.

The heads seem great in all other ways. Just be forewarned if you want to use center bolt covers, check this before you assemble.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

That was about the reply I got from World
A** H*** Products. But mine were already installed on the engine and " They said hand grind the bosses" great reply. MY solution was to mill the inside flange on the center bolt covers to clear the cast bosses. You would think if they are going to sell late 87 heads
for center bolt valve cover they would remove the D** bosses.

[This message has been edited by Z28DJP1987 (edited November 16, 2001).]

 

On my Pro Action heads, I decided to just buy new perimeter valve covers just because I feared just that situation. Hearing stories like that make me happy I spent the extra dough.

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1985 ASCD Ram Air Trans Am 350/5spd Pro Action heads, Comp cams XR282, Edelbrock Air Gap, if it can be changed it has Readers Ride at https://www.thirdgen.org/rides/index...ew&rideid=1067

-=ICON Motorsports=-

 

I don't think you quite understand. I had already removed the perimeter bosses - I knew that from comments on these boards and the instruction sheet they sent.

It's the RAIL width the entire length of the head that is too narrow. The bosses are out of the picture, and unfortunately, that means there isn't anything for the gasket, where it goes around the bolts, to press against. Leaves a gap so oil leaks around the bolts. I've filled them with silicone, but I've still got a little leak.

 

I would recommend you go out and get another set of centerbolt covers to try, or do whatever you need to do to get your current ones to work. Valve cover gasket leaks are real nasty under high pressure, you could start a fire, and nobody wants to see that happen.

Anthony

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previous ride: 87 Camaro LT
350, A4.Comp Cams 268H, Edelbrock Preformer intake, Hedman Headers and y-pipe, gutted cat, No AIR/smog pump. 14x3" Open element K&N, Q-jet w/ D hanger and DA rods, adjusted AV spring tension and quick can.

Current ride: 1992 Camaro RS, K&N, Flowmaster, 305, T5, Black, T-tops, 84k miles.

 

I think I may have finally gotten the last of the little leakers. I don't like oil on exhaust (I've got a story to tell about that, believe me). But, I don't like spending unnecessary money, either.