1955-1960

Greg Reimer 7376 · 10-27-2010, 10:36 PM

The heads on the 59 348 are the worst in the W motor family with tiny ports. That head is exclusive to the 348 block of that year due to water cooling passages-in other words, the 348 block in 58 can only be used with the 58 head. Later heads will result in a massive coolant leak by the spark plugs. A later 348 block topped with 58 heads would do the same thing. The World block is not only aluminum, but the bore size is way bigger than any maximum legal 348 overbore. The idea of the 61 Impala or Bel Air bubbletop with a 348/250 might work, and I think the hi-po 348 aluminum intake would be a legal replacement, since it was OEM. The '61 409/360 intake wouldn't be a bad choice, and some of the 4 jet carb guys are pretty good.Thirty years ago, a friend of mine in New Jersey had a 61 Impala 348/250 horse 4 speed combo that ran O/stock, went 13.00 at 103 back then. Broke a lot of rear ends.

10-27-2010, 10:36 PM	#6
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,136 Likes: 172 Liked 705 Times in 219 Posts	Re: 1955-1960 The heads on the 59 348 are the worst in the W motor family with tiny ports. That head is exclusive to the 348 block of that year due to water cooling passages-in other words, the 348 block in 58 can only be used with the 58 head. Later heads will result in a massive coolant leak by the spark plugs. A later 348 block topped with 58 heads would do the same thing. The World block is not only aluminum, but the bore size is way bigger than any maximum legal 348 overbore. The idea of the 61 Impala or Bel Air bubbletop with a 348/250 might work, and I think the hi-po 348 aluminum intake would be a legal replacement, since it was OEM. The '61 409/360 intake wouldn't be a bad choice, and some of the 4 jet carb guys are pretty good.Thirty years ago, a friend of mine in New Jersey had a 61 Impala 348/250 horse 4 speed combo that ran O/stock, went 13.00 at 103 back then. Broke a lot of rear ends.