[youngc0@mchsi.com]

I love 55 to 57 Chevy stepside trucks. I have a 55/56 made up of many donar vehicles. I purchased a 283 that was complete. the seller says it has 305 heads. The motor was built by one of his friends who moved away. My question is: What's the advantage of 305 heads over say 283 heads. Is it the design? When I look uo the specs the valve sizes are the same. Thanks

[DoubleVision]

Chamber size is close to the same also. The 305 head makes a good replacement head on a 283. One advantage is they have accessory holes so you can bolt on modern brackets, one disadvantage is they are on the light side, but this isn`t a problem as long as you don`t run it hot.

[Hippie]

Also they have hardened valve seats for unleaded fuel. Performance will be about the same. Definitely no disadvantage to using them on a 283.

[MI2600]

The 305 heads have a slightly smaller chamber, but larger valves than the stock 283 heads. As noted they have the accessory holes which opens up for differing bolt-ons. But, they also have center-bolt valve covers which do not look original.

[Hippie]

Originally Posted by MI2600

The 305 heads have a slightly smaller chamber, but larger valves than the stock 283 heads. As noted they have the accessory holes which opens up for differing bolt-ons. But, they also have center-bolt valve covers which do not look original.

Early 305 4 bbl. heads got 1.84 intake valves, early 305 2 bbl. heads have the same 1.72"/1.50" valves as 283's and both had the 4 bolt perimeter valve covers through 'early '86 just like any other SBC built since 1959. Chambers on both have been reported to vary from 55 to 60cc depending on the casting. The norm seems to be right at 58 for most 305's and for the 283 "Power Pak" heads used on the FI, 2 X 4, 4 Bbl's., '63 and newer 2 bbl. 283's and the '62-'64 327/250HP.

[youngc0@mchsi.com]

Thanks for the responces. Sounds like I need to get the casting numbers to determine the valve size and cc's. I will bw bolting on a A/C compressor on one of the heads. The comment about "don't run it hot" is good abvice. With a 55 Chevy truck you can almost stand next to the engine under the hood. Lots of air space. This should help with the cooling. Thanks to everone who responded.