Target compression ratio A/J
Talking with the guy thats gonna cut my cam we figured in a zero deck clearance and so with that in mind whats the best way to get there at this point, what way makes the most sense?
Wait!
Are you saying the cam has already been ordered?
Are those aluminum heads closed chamber heads? If yes, then IQ52 has got a recipe for you in post #6.
But if your cam has already been ordered, And with Scr of just 10.15, Your Dcr may get to be in the basement. This SCr will take a fairly mild cam to be a fun streeter.If the Dcr falls too low, you will be wanting a higher stall TC to get moving.Low DCrs tend to be soggy out of the gate. Aluminum heads suck heat out of the chamber. Heat that coulda been used to propel the vehicle. This lost heat needs to be compensated for with about a half a point of Dcr. This may take additional Scr to get. So if your cam is already on the way, you may have gotten ahead of yourself.
But if you are building a track engine, then this hardly matters cuz your hi-stall TC is gonna blast your car right thru and past the soggy bottom end.
AJs ramblings;
If I had a BB for my streeter, I'd want to run 3.23s. and a stock-type stall(2200 to 2400).And that would take a strong bottom end torque supply. And that would mean a conservative cam,and a matching Dcr.In this way, first gear would be good for close to 60mph, and 3.23s puts hiway cruising on the table. I would run a small vacuum secondary or AVS-type carb that I can bring the secondaries in as early as I want to, or as late as I need to. A double pumper will just destroy the tires. A spread-bore would be even better.In this way, I would attempt to not blow the tires away on every hard take-off. As a streeter I don't need a big cam, cuz there's that speed limit thing about 5 seconds after take-off.So I can't use second or third. And a 7000 rpm redline is kindof crazy if hit 60 at 6200.
3.23s will hit 60 at 6200 with a 2.45 low,and 5% slip and 27 inch tires. This would work well with a 110*cam that peaks around 5400, or a 108* cam that peaks at 5500, or a 106*cam that peaks around 5600. Or a 104*cam that peaks around 5700.These are pretty small cams.
In an A-body, I would go for the tightest LSA cam I could get to make maximum power, with a very rapid fall-off after the peak, cuz I don't need to rev to the moon. Look; with the BB,my tires are gonna be smoking anyway, so I don't need more low-end torque. I need a top end rush from 35mph to 60 so gimme that tight LSA.
If you have looked at BB dyno curves with 110 cams peaking at 5800, you might see the power curve nearly flat from 1500 before the peak, and stretching nearly 1200 after the peak. For a streeter, IMO that is crazy. I have to stop at 65mph or risk loosing; my car, my license, or both. So if my power curve extends to 7500, how does that help me? No if the engine gets me to 60/65 at 6200 then I don't care if 200 rpm later the curve hits a wall and drops to zero!, Right? So gimme that tight LSA,that will focus the power to a higher number over a more narrow rpm band.
So then IMO a small cam on a tight LSA is the secret to a BB streeters nightmare. Then put the power in the heads.
If I ever put a new cam in my Barracuda 367, it's gonna be something like 262/272/104. A roller. With mega-lift! And ported-for-street, Magnum heads. And a spreadbore. And it's gonna run on the edge of detonation with 87E10. So, I'm gonna run 87 in the front bowl, and 91 in the back dumps, and see what happens,lol.And Ima gonna gear it to hit 62mph (the speed limit here), just after the power peak. And I don't care if it takes 4 minutes to do the quarter mile.
Then Ima gonna work on the suspension until it pulls the wheels on the asphalt, in front of my house! And then Ima gonna tune that badboy, to get mileage like nobody believes. Hyup, I got overdrive.
Dreaming is so much good therapy.
