I'm ditching the air-gap and 750 demon for a stealth ram. Here are the specs on the motor

406
9.8:1
Hooker super comps/mufflex
Edelbrock performer RPM heads 170cc
Advance ~36

The cam (flat tappet)

http://cranecams.com/index.php?show=...21&lvl=2&prt=5

226/234 @ .050
.453/.478

I plan on using a Megasquirt II

My questions are

1) if tuned properly can the HSR make more power than an air gap and 750 demon?

2) Am I leaving a lot of power on the table by using a relatively small cam (for a 406.)

I ran a best MPH of 111 this year but the motor feels like it falls off a little over 5 grand (stock jets in the demon? small heads?)

The car is driven about once a week on the street and will see the track every two weeks this spring.

Thanks

 

I would say your heads are holding you back more than the carb/intake combo. I think your cam is actually pretty good for a 406. RPM range being 25-65 that cam you might even want think about a single plane since it's a minimum street use and strip car.

I would look for larger port heads and go to a single plane to make the most out of your cubes and cam setup.

But that is just my opinion.

Going to the HSR you will probably see some powerloss, EFI tends to make a little less maximum power, but you will see better driveability and most likely better fuel economy.

 

I would say the heads might be an issue as well. Especially the 170cc runner. With a 406 I'd opt for more in the neighborhood of 200cc or 210's. Also I'd increase the size of the cam as well. Duration is ok, but maybe some more lift. You could run a 1.6 rocker if not already to increase the lift instead of doin' a cam swap. Try looking at the comp xtreme fuel injection or XFI cam series as well.

 

Definitely agree with the lift, although your lift numbers are common for flat tappet cams. Go with 1.6's to get up towards .500 lift get the cylinders filled a little better.

 

Thanks for the responses, It looks like the heads are actually 185s

http://www.edelbrock.com/automotive_...erf_rpm2.shtml

would this still cause the motor to run out of air over 5g?

 

In my opinion your cam and heads are small for a 406 depending on where you want the power band. To answer your original question the HSR will work fine with that cam and it will probably have better mid range power and the same top end power as your current combination.

I would look for a cam with 230's in and 240's ex duration on a lobe seperation with .550 lift. A cam with specification similar to what I listed will pull strong to 6000 RPM and will still work fine with the HSR. Your heads are on the small side for a 406 but they flow enough air at .550 lift to support 6000 RPM. One other note your compression ratio is low for an aluminium headed engine. If you end up switching heads try to pick a chamber volume that will give you near 11:00 compression.