Regarding comparing the ZL1 to a ford 427, I thought it was an appropriate comparison, as both were basically the top engine options available as an installed in cars. SOHC's were never installed in cars. Although they only buiilt 71 ZL1's, as installed in vehicles, the ZL1 was just an aluminum block version of the L88, which they made a little more of. Both engines shared the same cam, piston's, heads, carburetor -- I'm pretty sure.
Steelcomp, it's good to find someone that shares their opinion that the 385 is Ford's version of the BBC, with Ford copying chevy's design, with some alterations. The engineer who designed the BBC even stated so about the 335/385 Ford's.
This has been discussed before to some extent.
BBF Wins PHR Engine Masters!!
I have to say your resume sounds extremely impressive, experience I wish I had, but I chose a different career, sometimes regretting it. Although the Ford has a higher deck, and bigger bore spacing, which makes it advantageous for very large displacement engines, the BBC I think was designed specifically for NASCAR 7 liter limit, 427 ci in 1964-65. I don't believe chevy had intentions of building 600 ci+ monsters that are being built today. Maybe you can shed some light on this, but I think there are optimal bore/stroke sizes for any given displacement, so even though the 385 has a bigger chamber, larger valves or unshrouding of valves, in a 427 ci engine, I don't think its advantage is that great over a BBC. At 600+ ci, I'm sure it would make a difference. SAme with deck height and rod length, at 427 ci, I'm not sure of the significance of the advantage. The BBC does have smaller rod journals, for less friction though. And, chevy has been very good in keeping basic design parameters the same between engines, allowing easy engine swapping, part swapping between different cars and parts, where Ford seems to come up with a different design for each engine, dampner's, flywheels. bell housings. distributor, engine mounts, etc. I don't think the BBC was a bad design for what it was intended for, and Ford just took chevy's design and made it better, in some respects, depending upon the purpose of the engine.
As far as cross bolt mains, I would think it is a better design than the splayed 4 bolt BBC / 385 design, but I haven't done/read stress analysis on it. I know that the 426 hemis had deep skirts and cross bolts. I assumed that when chevy designed the SBC an then the BBC, the smaller skirt meant less weight, not more strength, even with the 4 bolt mains. Regarding what Sizzler stated, about weight, I don't think chevy ever used high nickel in thier castings, and as such, the SBC, and especially the BBC, were/are heavy relative for their size. I read somewhere that Oldsmobile used high nickel castings, and as such, made their castings thinner, such that a 455 block weighs the same, or a little more than a SBC block. So I guess there was truly a need for an aluminum BBC block. I guess Ford followed the same design as the BBC as far as casting design went. Probably with thicker (heavier) casting, there was greater room for error with respect to core shifting, rejecting engine blocks.
In my opinion the 385 was not a total design for performance, it was designed for performance for a production based engine. To me, the Cosworth ford was an engine designed for performance. The best V type engine design I have ever seen was an Allison V-12, 1710 ci, 900 lbs, all aluminum, 4 valves/cylinder, twin plugs, most bolt shanks were undercut for weight savings. Truly a purpose designed engine - maximum reliability and performance for lowest weight. The guy down the street rebuilds them. Truly a better engine design than the often proclaimed Rolls Royce Merlin.
I enjoy all of this theoretical stuff, that is, for us hobbiests.
Threaded Mode
