72Vette + sb400 = 500+hp ????
Thread Starter
2nd Gear
Joined: Aug 2007
Posts: 2
Likes: 0
72Vette + sb400 = 500+hp ????
I've got a small block 400 out of a 71 gmc pickup in my 72 vette, but I want to build this up to produce over 500 hp out of it and I was told that this is possible in 400 sb,but how do I do it?
Thread Starter
2nd Gear
Joined: Aug 2007
Posts: 2
Likes: 0
as i said,I have a small block 400. I dont need to buy a crate motor,so yes I am going to build this one myself,but my question was, how do I build this engine up to pump out more than 500 horsies?? I don't want to throw in a blower. I want to keep the stock hood.
Should I bore the engine out? If so,what size?
Supercharger or turbocharger?
Nitrous Oxide?
What type of camshaft?
What intake manifold?
What carburetor setup?
What type of headers?
Please !!!! I need all the advice I can get !!!!
Thank You
Should I bore the engine out? If so,what size?
Supercharger or turbocharger?
Nitrous Oxide?
What type of camshaft?
What intake manifold?
What carburetor setup?
What type of headers?
Please !!!! I need all the advice I can get !!!!
Thank You
Instructor
Joined: Oct 2001
Posts: 155
Likes: 0
From: Corrales, NM
Omni,
I have a 400sbc (420ci) in my 80. It has a centrigifal SC (Vortech) and clears the stock hood. Haven't had it on the dyno yet but it will be way over 500hp rwhp. Anything is possible, it is just a question of how much you will spend.
Ken
I have a 400sbc (420ci) in my 80. It has a centrigifal SC (Vortech) and clears the stock hood. Haven't had it on the dyno yet but it will be way over 500hp rwhp. Anything is possible, it is just a question of how much you will spend.
Ken
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
500 HP is defintely possible from a small-block, and you're on the right track to get the maximum displacement to make it relatively mild - engines get more "hyper" and expensive as you move beyond about 1.2 HP/CID.
So; here we go - I expect this is going to be a long thread
I suggest starting with a budget to go along with the HP target - this will make more decisions for you than anything else The budget will tell you if you can afford forced induction, and if you can afford to build something that will stand up to a NOS shot.
Overall, you'll be building a big-inch small block with a forged rotating assembly, roller cam and big heads. Expect this to be about an 8-10K build.
So; here we go - I expect this is going to be a long thread
I suggest starting with a budget to go along with the HP target - this will make more decisions for you than anything else
The budget will tell you if you can afford forced induction, and if you can afford to build something that will stand up to a NOS shot.Overall, you'll be building a big-inch small block with a forged rotating assembly, roller cam and big heads. Expect this to be about an 8-10K build.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Just for grins, I worked up a mondo 400 SB in DD tonight to see what it would take. With a 4.00 stroker Eagle kit for 427 CID, Dart Pro I 230 heads, single-plane intake w/850 carb and a CompCams 12-432-8 hydraulic roller you'd end up around 500 (flywheel HP) that should be reasonably streetable. Peaks would be 514HP@6000 RPM and 496 TQ@5000 RPM. I'd probably consider advancing the cam 4 degrees to move those down about 500 RPM for street use.
It'd be a pretty rowdy engine
You'd be sitting on about 7K in the big parts (block, rotating ***'y heads and cam); figure another 2K or so for accessories, machine work and installation. 10K is a nice, round number you could commit to staying within
It'd be a pretty rowdy engine
You'd be sitting on about 7K in the big parts (block, rotating ***'y heads and cam); figure another 2K or so for accessories, machine work and installation. 10K is a nice, round number you could commit to staying within
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
You are right about the price. no real way to do it cheap. See my sig for 550HP, it was actually completly untuned as no tuning was done on the dyno. Since then I have dialed it in with LM-1 wideband and I figure it is closer to 600HP now 
It is a nice street motor with 460ft/lbs of torque at 2000RPM, it will smoke the tires at 50mph
It is a nice street motor with 460ft/lbs of torque at 2000RPM, it will smoke the tires at 50mph
Last edited by MotorHead; Aug 9, 2007 at 12:53 AM.
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Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
500 HP is very doable with a 400 motor. I would suggest since you are going to build it to put in a stroker crank for a few more cubes. A good set of heads is where you are gong to make your power. Couple that with a stoudt rollr cam and you will be well over 500 HP. I run a 385 SB with a radical solid cam and am just shy of 500 flywheel HP and it does 409 RWHP. Heads and cam are your power makers.
Melting Slicks
Joined: Jun 2002
Posts: 2,844
Likes: 99
From: Orrtanna Pa.
Mine's an easy 500 hp,but to be honest I've crossed the line with "streetable". I went low buck approach and got a good set of heads,and solid flat tappet cam.Turns 7000 rpms,but is a bit of a handfull in traffic due to the cam.
I'd ask yourself what the realistic budget is,and build from that.If 500 hp is all you want,get a 454 and drop in a Comp XE-284 hydraulic cam. I saw a build make 540 hp with stock heads doing that.Cubes will make it easy to hit 500 hp.
I'd ask yourself what the realistic budget is,and build from that.If 500 hp is all you want,get a 454 and drop in a Comp XE-284 hydraulic cam. I saw a build make 540 hp with stock heads doing that.Cubes will make it easy to hit 500 hp.
