I plan on getting it done a little at a time. I have a good 357C in the Falcon now so luckily I am not in a big hurry. Maybe ready this time next year.

I have to build the stroker to handle my centrifugal blower so compression needs to be tame. Probably a roller cam...

Got any ideas?

I?m kind of in the same boat as you. I?ve toyed with both displacements. I have three parameters within which I?m trying stick, all of which lean me toward the 393. One, is that I?m going to run ported Aussie heads. I feel pretty confident that they?ll provide enough flow for the smaller displacement; I?m not sure about the 408. Two, I want to be able to drive this on the street. All other things being equal, the larger the displacement will raise compression. I?d really like to keep it at 11:1 (or under) due to available fuel, although there is a local airport that I can probably get av-gas, if need be. Three, I hope to run nitrous sometime, and I think I need/want to stick to the Scat products, rather than try going with the cut down 400 crank, as tempting as it may be. Like you, I haven?t actually investigated cost for that process yet, but I?m thinking it?s probably a moot point in my case since I'm leaning hard toward the 393.

Actually, a more perplexing question for me is whether to build a 6? or 5.85? (either of them being SBC-sourced) rod 393. Based on factory dimensions, using a 5.85 rod and the 3.85 stroke permits the use of a 1.44 compression height piston. Based on a 9.205 deck height, it puts the piston .010 out of the hole. The 1.44 flat top pistons are used in 6? rod, stock stroke 351Cs, so they?re considered a stocking piston by many manufacturers (makes them cheaper than custom order pieces).

Some people may look at me cross-eyed and wonder why I wouldn?t just simply build the longer rod engine, so as to get the best rod length/stroke ratio and decrease cylinder wall thrust loading?both of which are excellent points. The 5.85? rod allows for a bit more space in which to package the rings as compared to the 6? rod, especially if it puts the wrist pin up into the oil rings. Assuming the 1.44 piston is a bit "taller" (and that would depend in part on skirt design, etc.), it would permit a more stable piston in the bore?good for better oil control, tighter cylinder wall clearances, etc. Part of my potential argument for considering the 5.85 rod is that I?ll probably use block filler to help stabilize the lower portion of the cylinders, so thrust loads won?t be the issue they would be otherwise. Finally, using a 6? rod in a 408 results in a 1.5 rl/s ratio. The 5.85? rod, with 3.85 stroke, comes out to 1.52?a tiny bit better than the 408. I?m not going to say there aren?t faults/oversights in my views of all this stuff, but that?s where I?m at currently (subject to revision).

As an aside, KB makes a hypereutectic flat top in the 1.44 dimension for the Cleveland head design. It is for a 6.2 rod Clevor engine.

quote:

---

Originally posted by futurattraction:
One, is that I?m going to run ported Aussie heads. I feel pretty confident that they?ll provide enough flow for the smaller displacement;

---

My opinion, nope. A severely ported 2v head is lucky if it flows what a 4v head does bone stock. Even knowing the you dont want to spin the motor, and are after good port velocity, I would still use 4v heads. A buddy I race with has a 377C with 4v heads, he only turns it 6500, and it runs extremely hard. I just think that the 2v heads will choke the motor badly, even the "small" 393.

The other thing I hope you can identify with, looking at your race engine update thread, is money. Changing to 4V heads would necessitate spending lots of $$ to upgrade to headers designed for 4V ports, different intake and camshaft, lower gears, higher stall, etc., not to mention the work involved. My wife would probably disagree with my description of the Fairmont, but it IS a hobby--not an obsession. All of those 4V related changes would require that much more time investment...not good for the marriage! Besides...I've got other areas that I consider more pressing as far as spending is concerned. Current plans for the Fairmont are that it will spend the bulk of its use being street driven. Even if I decide to race it more seriously, I'm willing to start with a milder engine and go from there.