Calling All Engine Builders
 

I've decided to rebuild my 402 BB from my 72 Longhorn. It's using a quart of oil every 150 miles. My goal is 425hp-475hp plus about tha same in torque. Keeping money in mind, I would like to get opinions on combinations and or modifications. I have a freshly rebuilt th400 behind it.:flag:

bore it 30 or 40 over and a nice heads and a decent cam and you'll reach that mark.

i concurr with my new 72, a good set of heads, and a nice cam and good CR would take you up there. Port those heads if you can and do all the matching possible. A nice hot cam with a good CR would take you to fun places, I'd say if you're building it for some nice power take the CR as high as you can with the gas you have available in your area.

Big 69, this was copied and pasted from a racer on team chevelle, he got that power level out of the 396 no problem on a budget. You could substitute a Holley 3310 and an rpm manifold, he used to run 11's in a full bodied Chevelle.

402 w / 10.3 to 1 compression (calculated)
Edelbrock Performer RPM Q-Jet Manifold
Q-Jet carb w / 75 main jets and 45B rods, AX secondary rods on a G
hanger
1 3/4" primary tube headers w / 3" collectors (go with Dynomax)
Factory lifter valley heat shield
Factory carb heat shield and 1/2" phenolic spacer
Moroso 6-quart oil pan
Factory windage tray
TRW aluminum water pump
Factory 7 Blade thermostatic clutch fan
HEI with power coil and mod.
Ultradyne hydraulic cam - 280/288, 223/ 231 @.050 with .525/.550 ground
on a 110 LSA and installed on a 106 Intake centerline with matching springs
Crane long slot steel rocker arms
Factory balancer
Felpro gaskets
Turbo 400 with transgo shift kit full auto valve body
Factory deep pan
ATI 10" converter # 408360(73P)
12 bolt with 3.73 gears
stock front and rear suspension with 1 3/8" sway bars and No-Hop bars
Polygraphite bushings
3" head pipes with 3" crossover and 2 1/2" tailpipes with Flowmaster
Big Block Mufflers Series 50
Mallory Comp 140 fuel pump and regulator
Factory 4-core radiator
This combo was driven anywhere and with the Q-Jet got 13 MPG on the
highway. With this cam you shift @ 5800 and with this valve lift you don't need
a roller rocker. If it's a square bore carb you want then go with the HP
series from Holley and stay away from the Demon which I believe is
junk. If you have the $ and want to step up with the 396, I'd go with a roller
setup. The problem is though that nobody makes a roller small enough for this
combo but you might want to give Comp a call and see if they'll custom grind
you one. Tell them you want a cam that's 232 / 238 @ .050 with .633 / .640
lift ground on a 108 LSA. This cam doesn't exist but they can grind it and
it has my intake lobe as an exhaust lobe for your combo. Don't let them
talk you into anything else. This setup will be 4-5 tenths quicker in the
1/4 mile and make power in the same range. However I don't recommend this
for a daily driver rather for a weekend max effort car that will see regular
trips down the 1320. BTW, this setup will set you back $1000 for everything.
Still the key to everything here is having those heads done by the right
people. Ideally you are looking for a shop that builds stock and super
stock motors and this work should cost about $700. If you are assembling the motor make sure all your clearances are dead on.

oval port heads with 2.19/1.88 valves, RPM intake, 10:1 compression, cam with around 225-235 duration@.050 and 1 3/4" headers will get you where you want.