I was typing mine while yours posted and hadn't looked yet. Not disputing your post. Seems like all are stating kind of the same things from different angles. (Awww, how acute...Stop being obtuse!...No, I'm right!)
I ran that Crower cam @ 10.5 compression in my program. 4 degrees advance is built in so straight up is really 4 advanced. Retarded 4 degrees (really straight up) worked the best. 365HP @ 5500RPM, 378TQ @ 4500RPM and 7 Dynamic compression.
Hmmm now its got me thinking, didn't Dave Nelson's build in Hot Rod end up with about 10:1 using 300 rods? I'm wondering if notching the pistons and just rebuilding the rods is going to be cheaper/easier than figuring out the nascar rods. I don't want to start another World War Rods but the ratio with the 300s does give me pause, not to mention the increased durability you would have with the nascars. I haven't really settled on a cam as I've been trying to just get a strong bottom end with a "flexible" cr. I'm thinking that if there is one area im going to splurge a roller cam might be the best bang for my buck as far as overall improvement. Plus I figure I can always change or modify top end parts later if the desire strikes me.
Figure out what the engine is going to do power and torque-wise based on airflow. Finalize bore/stroke as to how your figures fall according to the cylinder size/rpm capability...with budget and the range of compression ratios physically obtainable in mind. Finalize the compression ratio with the vehicle it's operating parameters, and your geographical conditions/fuel availability in mind.
We used the 350 capscrew rods and short 1.19 compression height, Hyper late 90's Ford Ranger 2.5 pistons in Chris's build. The earlier rods are lighter and can use SBC rod bolts. Another thing we did was use 350 lifters and oil through the pushrods instead of the rocker shaft. The Hot Rod motor Dave Nelson did used iron heads also, much better ports and valves.
According to the calculator I used, stock 64' heads (which flow about 150cfm in stock trim according to Dan Jones) should support about 4500 rpm in a 349ci 8 cylinder, assuming 100% ve. I don't see myself trying to spin it over that anyway. My main concerns are driveability and efficiency. I really went back and forth about whether or not to even stroke it, but with the crank so accessible and the fear of future regret I decided I will try it. What are the benefits of not oiling through the rocker shaft?
In my opinion, more precise oiling to the individual rockers. Having owned 215,300,340 and older V6 plus later 350's and V6's. As the shaft wears the top end gets flooded with oil with the older system. Much more controlled in the later system. I also don't like the aluminum rockers. I went through about six sets mixing and matching until I found a good set for a 215 I rebuilt. As to Roller cam and lifters I couldn't justify the expense. The Turbo V6 guys found that you could use cheaper FWD shorter V6 lifters. Then can be upgraded with LS springs and circlip. You can even make them solid by removing internals and using a steel tube under the cup. Then you would have to find or make a spyder to hold down the dogbones. Then there is the expense of the cam. Art on BritishV8 has blanks and Delta Cams can regrind.
If you are talking about a 4500 rpm engine with 150 cfm heads and have zero intentions of upping the top end's capability with different heads or extensive porting, then there's little point contemplating serious crank, rod, cam or other mods. There's also zero reason to think a 6200rpm engine would have any less capability with respects to driveability and efficiency if the discussion focuses on boring, stroking, oiling and head work. If you pick the right parts and pieces first, the budget is perfectly do-able as a close-to-stock rebuild. Gotta develop a plan at this point.
Duffey, I ran my program with the iron heads, mild porting and gained 30HP, T/A out of the box added 60HP. That was with a drop to 10 to 1 to lower the Dynamic compression back to 7.
Thanks for the input Jim, I will have to consider that once I get to the top end. For about $1500 I can have the 64' heads flowing close to 200 intake and 150 exhaust at .500 lift. Which leads me to my reply to f85-- I would say I have more than "zero intention" of upping the flowing capability. I'm simply focusing on the bottom end because that is much harder to change. Am I incorrect in thinking that as long as I build a strong bottom end with around 10:1 compression and proper quench that my top end options are virtually limitless in regard to future goals and budgets? Even multiple iterations if need be?
Yes, That is just one example. I like Erson cams also. There are not a lot of options for the 215, 300, 340 cams. Delta can regrind whatever you want from your stock core. I have found that if I go up to 7.5 I have to cut back timing and use Octane booster. At around 7 I run pump 91 with no issues. Quench is a non factor with the aluminum 300's open chamber.
I wouldn't say 'incorrect' but I do things very different. There's a reason I cited the example I did above. I have someone else's $9k failure to sort out and solve and this could easily be you . I would keep the number flexible and determine the range of compression after you decide everything else, as stated before. It isn't productive at this stage to lock that down (I'm assuming you are referring to a .5 or so leeway). I wasn't sure if you were just using an example that was set in stone and hoped there was still a plan to grow. Text/type can be limiting The heads and induction will determine the power levels and the rpm range based on the cylinder geometry. If you want it to come in lower and with more torque before it starves out, then add stroke. Add cam after that to help shape the curve for driveability, response, etc..
I am always grateful for the input f85! And your are correct in the leeway assumption. Now, I'm assuming that offers grinding the 340 crank would increase interference with the cam? I'm just trying to figure out what my options are as far a rods/pistons go in achieving my desired cr. Also, I understand the crank needs to be machined for a particular seal?
Regarding compression and achieving a certain number, I budget in and take for granted at the same time the fact that I have no issues cutting .100" off a head, block, or the top of a dished piston to make the parts selection more flexible (arbitrary #'s, not meant to be specific to the thread) . Time vs. $$ dictates the customer pays for a part that drops in but if the choice is a $200 piston that needs a trim vs. a $700 custom, both sides benefit the in-house modification. There's a certain amount of truing things up and if you keep that in mind before final parts selection you don't have to spend twice. That's the pragmatic reason for keeping a range for compression and various recipies researched and on-hand.
Sean, Yep, on Canadian Chris. I'm a little balder now from helping him figure out the Megasquirt EFI, and I was a USAF Electronics Tech and now a Power Plant Operator. Fitech and Holley Sniper are so much simpler.
