Isky RPM 300. 228 deg. @ .050, 3.89 or 4.11 gears.

"FREE SAMPLE"

55blacktie,
Thanks for the input.  Having the overdrive working and using it was the start point of the project.  I'm figuring I'll have to take the cam down at least one size (defined as 7degrees at 0.050") to get sufficient power at 2300 rpm.  I have targeted OD cruise of 73 mph turning 2250 at ~19 mpg.  I might need to go down two sizes, but want to retain as much lumpity at idle to make it clear this is not a stock cam.
Any thoughts on the carb side?
Sweeptee

57 E 'Bird Customized for Glory

Sweeptee, I'm sending an email.

I have a repop "blower cam" that Mummert produced around the late 90s, early 2000s.  The specs are 226@.050, 274 advertised, 112 separation,.295" lift.  It has a clearly not "Stock" sound (although maybe it does sound stock if it is a copy of the correct cam but you know what I mean).
This cam does fine in .62 OD, with 3.70 rear gears and 28" tall tires, with 318ci.  In that configuration about 1800 - 1900 rpm is 70mph and while the engine clearly likes to be above 2000rpm, it did fine with that.  I imagine that the 112 separation has something to do with that.  A 4.11 rear gear probably would be better, but most overdrives are not as tall as .62 which might make a slightly taller rear gear fine, depending on the transmission.


Lawrenceville, GA

You will want a narrower LSA for "the sound." Mummert's Y-280-1-07 cam has a 2200-6000 rpm range. Its 107 LSA should give you the sound  you are looking for. The narrower LSA should also provide a little more torque at lower rpm. However, there won't be a lot of vacuum at idle. 19 mpg? Maybe on level ground, light traffic, and constant speed. A wider LSA should improve mpg and will provide more vacuum, but will diminish the sound. Everybody wants the perfect cam, but I don't think anyone has found it. There are just too many variables to consider for a street-driven car. More than likely you will have to give up something. Consider your driving habits. How you intend to use the car, and how often, should be primary considerations when selecting a cam. 

Again, thanks for input.  Really appreciate the descriptions of your vehicle, performance and cam specs.  This is exactly what I need.
55blacktie, I'll be on the lookout for the email.  And yes, Mummert's Y-284S is almost exactly what is in the car now and it is just too much for what I am wanting to do with the car.  Might work okay with a single 4bbl and an interest in constant tinkering and frequent track time, but it's too aggressive for how I'm using it.  I really like your idea of the Y-280-1-07 and the tip regarding LSA.  Seems to be in the sweet spot of what I'm trying to accomplish.  I'll be adding headers to the equation...  ;-)
Charliemccraney, thanks for the numbers on drive line ratios.  That really helped to confirm my calculations and also provided some level of confirmation about what my father told me when he ran the car in the mid to late 60's...  "I got close to 20 mpg if I kept it just over 70 at 2200 on a long highway cruise"
Sweeptee

57 E 'Bird Customized for Glory

I hate to add another level of confusion, but I've been thru this. I ran a 9:1 motor in my bird with the 270 Mummert cam. Great combo. But when I put the Mummert heads on with the small chambers, and went to 10.5:1 detonation became a real problem. We eventually worked it out with the timing curve. I don't pretend to fully understand the issue, but if you're going to less cam and you're at 10.8:1, you might need to look at the dynamic compression ratio as well as the static ratio. Ted Eaton and John Mummert were a lot of help to me on that and I've since done cam change. Hopefully he'll chime in.



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Miker,
A worthy consideration.  What gas were/are you running?   I've had dieseling as an issue, but haven't had to slay the detonation dragon thus far.  I also do not consider myself an expert in any of this.  I do know that timing (or lack thereof) has been an issue on several of my rides.  Thanks for the heads up.
Sweeptee

57 E 'Bird Customized for Glory

I was running 91-92 octane ethanol gas. Max 10%, but I've never checked it. The high priced racing fuel solved the problem-couldn't afford to drive it with that, but it didn't ping or detonate.

Solving the timing problem was helped by the fact it's a EFI car, and the computer controlled the timing. It doesn't have a smooth curve. If I were doing it again, I'd cut or replace the pistons and get back to 9 or 9.5 static.

I'm outside Seattle, 0 to 600ft above sea level. Whereabouts are you?

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Sweeptee, I sent the email this morning. 

Check out gofastmath.com. You can calculate your dynamic compression and horsepower. I0.8 static is pretty high. Milling the heads and zero-decking the block, alone, won't put you there. You must have pop-up (domed) pistons as well. A smaller cam will increase your dynamic compression ratio, as Miker said. E-85 might work, if it's available in your area. It's cheaper, but your mpg will be lower. I've not converted to E-85, but maybe somebody out there has, who will give you his 2 cents on the matter.