I'm looking at various cam profiles. Thanks.

mark




[Modified by 81vette, 1:37 PM 12/5/2002]

 

My NA SBC 427 only pulled about 7-8" of vacuum at idle and the headlights and HVAC still worked, albiet slower. Sometimes I would have to 'blip' the throttle to create more manifold vacuum but it wasn't that bad. The cam was a 256/264 @ .050", 112LSA mech roller.


[Modified by Monty, 1:42 PM 12/5/2002]

 

I'm with Monty on the blip the throttle idea. I had a large H-flat cam and I was heading up the freeway out of Salt Lake city Utah. It was evening and getting to be the time to pop the head lights. I was going 75 -80 mph or so up hill and they didn't open so I let of on the throttle and shifted down to get them to come up. I never had brake booster problems or even considered a vacuum reserve. It was in the 7-8 range at a 800 rpm idle.

Right now backing out of the garage and turning on the headlights is iffy unless i bring up the rpm.

 

Thanks Monty, that's what I needed to hear.

BTW, my project here is slowly going together. I'm still planning to use the TKO that I bought from you in place of the 4 speed. I've purchased all of the 406 bottom end parts, and will soon get the AFR 210 heads, cam, and Holley 950 MPFI. I had some problems with the SRP piston diameters being out of tolerance for the set, so I sent them back and I'm waiting for the new set to arrive. Meanwhile, I'm about to pull the body for frame and rear end detailing. I hope to have it drivable by next spring, but that's probably more than a little optimistic.

mark

 

gkull,

My cam will be a little smaller than yours and Monty's, so from what you guys are getting I should have no problem. I plan to use the hydraboost, so the brakes won't be a problem. Thanks for the reply.

mark

 

A 415 should create good vacuum with any kind of roller cam that is streetable. I wish I could get down to your cars weight.

 

Wow, you're tackling a pretty big project, pulling the body off and trying to get the car back on the road in the spring. I guess since summer officially starts in mid-June, you've sitll got 6 months. I guess we know where you'll be spending your weekends and evenings!

That sounds like a really neat combination you're putting together. That 406 with the 210 heads and a good roller cam shouldn't have much trouble getting close to 1.2hp or more per ci which would give you an honest 500hp or so. i ran those 210 heads on a 383 about 3-4 years ago and they worked pretty well, they'll work even better on your 406. Good luck with it, and I'd love to see some pics along the way!

 

Monty,

I'm using DD2000 to get at around 540 HP at 6500 RPM with the cam I've picked. I've been messing around with cam specs in DD2000, and one thing I've noticed is that there are big differences in the HP/TQ/RPM outputs in DD2000 when entering the cam specs using advertised duration verses the .050 figures. I'm getting both cam specs off of Cranes website for the comparison.

The DD2000 help file says to use the advertised figures rather than .050, because they're more accurate :confused:. It also says that DD2000 converts .050 to advertised duration anyway. I was always under the impression that the .050 specs were more accurate, but apparently that is only true when comparing the specs of different cams to one another and has nothing to do with the actual power they produce....or so I read. This doesn't make sense to me, because I thought at flow numbers below .050 lift there isn't really much happening in the way of flow.

When I used the .050 figures DD2000 shows better torque down low, but with advertised numbers it shows better HP up top and increased RPM's. Anyway, if I can get close to 550 HP and still be streetable then I'm good. I think from the cams you guys are running I should be ok. It'll be interesting to see how close the actual numbers compare to DD2000 when it's all said and done.

mark


[Modified by 81vette, 6:35 PM 12/5/2002]

 

I always used the the .050" figures as well because as you mentioned there isn't alot of flow prior to that. Also it's just easier to compare cams, which is really what that program is good for. I wouldn't put absolute faith in what the actual hp/tq numbers it predicts are, but it's good for comparing how different combinations and specs can effect the power and torque curves as a whole.

 

Yeah, I was kinda hoping that if I put together a combination that "claims" 540 HP at 6500 RPM that I should at least get 500 HP out of it. 10% fudge figure. Hummm......maybe I should build in a 20% fudge figure just in case. :D

Talk to you guys later.

mark