I have a 428 cobra jet i am building to put in my 69 mach 1 in place of the stocker. I will be running 10.1 compression and the heads flow like this.
-------------Ford CJ--
lift-------intake----exhaust
0.050-----34.0------20.8
0.100-----75.7------46.0
0.200----150.0------84.8
0.300----202.0-----118.1
0.400----228.1-----145.3
0.500----235.8-----162.7
0.600----242.9-----173.9

The car will have headers and a good 4 barrel carb set up. I want 400 + rwhp. I was thinking of a custom grind comp like the CC 306. They make a Hydraulic flat tappet and i was thinking of a custom 230/244 on a 110 LSA cam. The lift would be .530/.560 on the cam. The only thing i have to worry about is power brakes. The car is a 4 spd and has 3.90 gears i may put in 3.50's. I probably won't rev beyond 5,500 these 428's are getting rare. Is that intake to exhaust flow ratio good? i noticed comp only makes single pattern cams for this motor. I think the max i could go and be a good street car would be 244/244. I would go to the ford forums but they wouldn't be able to help as much as you guys. Any thoughts or input? Thanks guys.

 

I would go with something in the 245/250 range at .050 Lift .550. The flow numbers are not great so you need some decent duration to make up for it. Go with something around a 112 lobe center as this will make sure you dont have any problems with the power brakes. This should also allow enough overlap so you dont detonate at low rpm.

 

I'm going to say a soild flat. You can get in there and adjust the lash once a year can't you? It's not a LS1 where that would be a complete bitch to do. Hell a .018 feeler guage and some sockets during the spring check up will be easy enough to do.

Going off of a Comp Cams Tight Lash lobe for the intake, I would go with a 114 LSA, since it's going to help with your vaccum the most. You can always advance the cam, and still keep the vaccum. Say 2-4 degs, that will give you a Intake Centerline in teh 110-112 range. I'd try it straight up first. A 112-110 LSA will get you a choppier idle and most likely no more power. I would just adjust the distributor springs and weights for less ign advance if you run into detonation. Doesn't look like it to me.

Then since your average E/I ratio is 64.4 you need ALOT of exhaust timing in relation to the intake. I would look at something like a 242/262 .588/.588

You gotta remember that the flat tappets make it act like less of a cam because they have less lobe area.

I would guess that a 242/262 will idle ALOT like a C306 in a LT1.

Go with a 850-870cfm carb. A performer intake (with RPM or regular will work, I'd go with the RPM PN7105) if you want to spin some more RPM a single plane would make more power. (Victor FE PN2936) I'm guessing you want to keep it below 6000rpm, still a Victor would make a good street intake still since those FE motors have such a wide lifter valley and REALLY long intake runners.

So with all of that, I would guess around 420rwtq and 380rwhp with a RPM intake. If you had more head flow, there is alot of HP there. A Victor is going to give you about 430 rwtq and 410rwhp, with max engine speed below 6000rpm. Keep the 3.90 at least too.

So my advice. A Comp 33-000-4 cam blank with 6314/6218 lobes on a 114 LSA. Solid Lifters. Comp 924 springs, A 850-870cfm 4bbl(I like vaccum secondary carbs, so that with a light spring in the vaccum will work well for you), and a Victor FE intake. That should get you too your goal, it will idle well enough for power brakes, pull hard to 6000rpm and make 400+rwhp. That's going to be a nice combo in a 69 Mach. My brother in Law has one with a 351W in it right now that he's tring to sell. Once the new clutch is in, I'm going to run him down with my LS1 SS.

BTW I also have a orginal FoMoCo Sidewinder Aluminum intake for a 428. It has a cheater N2O system plumbed under the intake from the 70's. It works and is completely bad ***. Don't know how much all of that is worth though. My guess with the prices of muscle Mustangs now adays, it's worth alot.

Hell on top of that, There is a 408W stroker here. I needs work, but it could be a 600hp Terror with the right setup.

I hope that helps. I like these odd cam questions. One day soon hopefully I can sell you all that stuff on top of it all.

Bret

 

Flat tappet sounds like a winner. You can also set the cam "straight up" and use a vacuum pump as an alternative to keep vacuum alive. Since we're on the subject, what is the trade-off in retarding a cam 2* to 4* for vacuum retention? (i.e. Going with more of a "spread" built in the cam vs. running the cam "straight up" and reducing the LSA...)...

 

stroker ace i thought you wanted a lower LSA because that raised the DCR.

 

yeah but old school you can just advance the cam a few degrees. its the ICL that gives you your DCR.

 

Turbo_Z is right, just advance for more DCR. I wanted the 114 LSA to make more vaccum due to the large duration of the lobes, because all that duration makes alot of overlap by itself. Seriously with a 114 LSA you should see vaccum levels of a 350 LT1 with a C306 in it.

Bret