Are the 305 World heads worth buying and maybe porting polishing and shaving or would it be the same to just do that to my stock 305 heads. I have a 91 305 tpi z28 with 3.73's and a lot of other stuff. Would it even make a difference if I got these heads?Please help me out. Thanks

They will make a difference even over ported stock heads. But, they need some help out of the box. The S/R Torquer 305 heads do NOT, however, require shaving, since the chambers are already 58cc.

Before I even ordered mine, I emailed World asking what, if any, porting work they recommended, saying I was considering following the guidelines put out by Standard Abrasives. Their response was to endorse the SA method, but said "concentrate on the bowls". Every test or evaluation I've seen of these heads included bowl work (also called pocket porting), and when I saw the as-delivered parts, I understood why.

I went ahead and did the full SA treatment on them. I have no clue how much improvement they made over stock heads or pocket-ported World heads, but I do know the car runs awesome.

Popular Hot Rodding did a TPI dyno evaluation last year of these heads, pocket ported, vs. 3-angle valve job stock heads. The difference was 50 hp with a Comp Cam that was close to stock (in fact, the baseline engine, which was a fresh .030-over rebuild, put out 190 hp, the same as the LB9 rating) - a bigger cam would probably show greater increase with the head swap.

Another advantage, other than the improved port flow, is an improved chamber design. In fact, this change in chamber shape leads World to tell you to use a 350 rather than 305 head gasket when you put it back together. Interesting. Plus, they use screw-in rocker studs vs the factory press-in (screw-in more reliable), 1.94/1.50 valves, and have a thicker deck casting. In general, the casting is higher quality than the factory pieces.

Only nit I had against them is the '87 centerbolt valve covers I had would not fit between the rails of the heads - not discovered until the heads were already on the engine. I had already removed the perimeter bolt bosses (per instructions), but hadn't checked that dimension because I didn't have any cause to. I reused my perimeter covers, but since part of the boss was already removed, sealing problems were the result. When I wrote to express my disappointment to them, they responded that this comes up every once in awhile, and they had a set of later truck valve covers to use as a check tool - their covers fit just fine.

Okay, long response, but the short of it is if you're going to put a die grinder to a set of 305 heads, make the heads Worlds'.

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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. ZZ3/4 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).

How much HP/TQ gain will there be with those heads & cam?


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1992 Camaro Z28
Stock
5 Spd

For the price, I would spend the extra 200 bucks and get the trickflows. If cost is not an issue, AFR's. I read a head comparson and the world torquew 305 heads improved flow over stock, but not by much as compared to the difference of the trickflows. And the TRickflow's are only 200 more that the world products. JUst my .02

I was thinking of going w/ the same heads. I don't know much to tell you about 'em but do a search, there have been several of these topics. Most I've heard about them were good.

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'91 RS
'86 IROC-Z(project)
#3

TFS 23's and AFR's are not going to work very well on a 305. The exception may be the AFR 180's. I believe your best bet would be a set of 'Vette L98 heads if emmisions are not a concern. Have the bowls ported and have a valve job done. The L98's have 58cc chambers. Aren't 305 heads supposed to be 54cc's? I could be mistaken.

You are indeed mistaken. All factory 305 heads had 58cc chambers.

The Vette L98 heads are not better than the World 305s for a 305 for two reasons:
1) They are designed for a 350, even though the chambers are 58cc, so the chambers are not optimized for the smaller 305 bore - the Worlds are;
2) The L98 aluminums, even though made for a 350, are 58cc for a reason - aluminum requires more compression than iron to make the same power. Although you would maintain your static compression, your effective power would be reduced.

Add to that the lack of the crossover passage you mentioned, and that flow isn't better over mildly ported World 305s, and you're spending your money in the wrong place with Vette aluminum L98s.

The only benefit would be reduced engine weight. With the same power (which you aren't going to get), that is worth about a tenth or less in the quarter.

[This message has been edited by five7kid (edited December 06, 2001).]

I stand corrected However.....

1) Both the L98's and the World's are a "open" chamber design. The valve spacing and angle between the 2 is identical. Neither of them would be my choice since they are both a 20 year old design but they are well priced (relatively).

2) The L98 deck's can be safely cut to 54cc's which would give a nominal compression ratio. If you where to spend an eaqual amount of money on each head (L98/World) I believe you would come out ahead using the L98's.

[This message has been edited by Acceld Z (edited December 07, 2001).]