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Original Message
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| On rare occasion it can be done properly. |
| By Dave Shoe - 09/30/2001 2:43:38 AM; IP 216.243.158.34 |
Anyone can bore a 360/390 block out to 428 dimensions, but if you collapse a paper thin cylinder, don't blame Ford.
The 360/390 block is absolutely different from the 428 casting. The 428 welded "A" casting can generally be bored to 4.160" (+.030) and the 428 welded "C" casting can sometimes be bored to 4.190" (+.060), core shift permitting
360/390 blocks can generally be bored to 4.110" (+.060), core shift permitting, but taking them to .080" is just making a thin wall thinner. The cylinder jackets are NOT cast the same as 428 blocks, so why pretend that they are? You can either build a durable 390 from a 360/390 block, or you can build a delicate 428 engine which needs a 2V intake and avoidance of high revs to keep it alive.
Only a sonic mapping of the block will tell you whether you can bore a 360/390 block more than +.030". I've got a couple 360/390 standard bore blocks that cannot handle even a +.030" overbore without weakening themselves beyond any kind of performance use. Only offset boring will allow these blocks to see mild performance use.
The 361/391 FT heavy truck block is generally a good candidate for heavy overboring. You can find these in Ford series 600-800 trucks from 1964-78. Also, some lighter trucks sometimes got these blocks, but not very often. More often, you might find an F500-series truck block with some FT features, but not with the heavy cylinder walls of the FT. The genuine 361/391FT block can frequently be converted into a 428CJ equivalent block.
Be careful about rushing to convert a 360/390 block to a 428. Most of those magazine writers who claim the .080" overbore is so desirable have never built an FE first hand. Most of those writers are full of crap.
Shoe. |
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