[72bu]

72 Chevelle, 3,500-3,700 lbs (?)
406 sbc, 4.155 bore
6" rods
Dart Pro 1, 200cc intake, 72cc chamber, 2.02 / 1.6
10:1 compression
1.5 rockers
Victor Jr (current, could switch to RPM Air Gap)
750 cfm carb
1-3/4 primary, long tube Hooker Super Comp, 2.5" with x-pipe
Richmond 5 speed (3.27 / 2.13 / 1.57 / 1.23 / 1.0)
2.73 gear
27.5 (current) or 26 (possible) tire

Street performance only. Also, I have power brakes and don't want to run a canister or pump.

Car had a Comp XR276HR-10, but the fuel pump lobe got wiped for lack of a bronze-tipped rod. Also had a 3.07 gear and now has the 2.73.

I got a tech recommendation for a Howard's 111145-12 (219/225, .525/.525, 112 LSA, 1500-5600) or Lunati 20120711 (219/227, .515/.530, 112 LSA, 1800-5800) and to change to an RPM Air Gap. I may also go to a smaller 26" tire, especially if it would helpful to bump up the 5th gear rpms a little. Are these cam recommendations on the mark with the compression, trans., rear gear, etc.? FWIW, my builder suggested going a step bigger than the XR276HR-10 to something like 230/236, .550. I think that would be too much cam/too high of an RPM range. I thought about the XM276HR (112 LSA) but that also seems big with the 2.73 gear?

I have relatively little knowledge/experience picking a cam, so help is appreciated.

 

[ExcellenceAuto]

That tall gear in the rear is really gonna limit you.
With a 26 inch tire and a cruising rpm of 3000 you are going 85 mph. (see pics)
If you do lots of highway cruising this would be good. And you would stay with modern cars right up to 150+ mph. That's Fast!
So going with maybe a 3.23 rear gear might suit your driving style better, and allow you to run more of a midrange and upper cam.
You keep your 27.5 tire and at 3000 rpm you are cruising at 76 mph. 3300 rpm gets you to 83 mph. Not bad at all on the highway.
The 400 makes good torque, and your car is not super heavy and has a nice, low first couple of gears. You have a good base motor to make some power.
You want to do some soul searching on if you want to make good, or mediocre power. Your intended use. And will you want more, or be happy with some?
More guys will come in with way more experience than me.
And power brakes... That's a different story. One that will keep your motor in the medium range. But, let's figure out your gears first! LOL!

 

[ExcellenceAuto]

Spicer has a nice calculator to play with.

 

[72bu]

Thanks, I do understand I'm limited with the 2.73 gear. But the Richmond 5 Speed is designed to work with a 3.08 gear and a lot of guys run 2.73 instead. I don't think anything taller than a 3.08 would work me because 1st gear would be too tall and I'd rather not change the rear gear because that would involve a carrier swap too. It's got a nice 2-series posi in it.

 

[ExcellenceAuto]

That @!ch is gonna scream on the highway! Hope you have some good roads in your town.
And yes that is probably an ok gear for the street. You can go about 45mph in first gear! 70 in second, at full boogie.
So you will want a good torque cam. But it needs to be more than that 276. JMO. Hopefully you can get a good recommendation soon.

 

[72bu]

I misused the words "tall/taller" in my prior post (shows my lack of experience). I think the trick is going to be finding the right duration/rpm range but what do I know! At least I'm pretty sure I should switch to a dual plane for more torque.

 

[ExcellenceAuto]

I misused the words "tall/taller" in my prior post (shows my lack of experience). I think the trick is going to be finding the right duration/rpm range but what do I know! At least I'm pretty sure I should switch to a dual plane for more torque.

Yep. Dual plane for sure. And vacuum secondary 750.
I'm no expert either, but these guys will find you the perfect combo for what you are after. You could also call Straub, or Mike Jones. Howard may have even nailed it too.
I like the 230/236 but you might not have enough compression, and probably too tall of a gear for that.
But then again, I'm just a toddler still.

 

[johnsongrass1]

Custom cam is your best bet.
those heads are pretty big in the ports to get decent flow numbers so I’d stick with one of the cams chosen for you already.
A 1.6 rocker will help.

 

[ericnova72]

I'll add the change from a Vic Jr to an dual plane on a 400 isn't a smart move. Typical SBC dual plane runner cross section is planned around the peewee 350, it will hurt power on the 400" while not really improving torque enough to be worth the swap.
If it has to be a dual plane, maybe the Brodix HVH
Might want to read this thread from Chevelles.com

Edel RPM Air-Gap = HP Killer

Had the opportunity today to do an "apples-to-apples" test on a pump-gas 383". First couple pulls used a Professional-Products "Super-Hurricane" #52036. Made 462 HP @ 5700 and 450# Torque @ 4800. Bolt off the P/P and bolt on the Edel 7501, after a couple pulls, 413 HP @ 4800 and 450# Torque...

www.chevelles.com

Fill out this guy's cam recommendation form and see what he says, he is good....You'll find him on several forums as "CamKing", Mike Jones, Jones Cam Designs

Street Performance | Jones Cams

jonescams.com