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400 Small Block: How To Build A Torque Monster For $2,500!- Hands On

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If you're a hard-core Chevrolet small-block engine guy, the good news about all the attention the LS engines are getting is there's never been a better time to build a budget Gen I small-block. That even applies to the nearly extinct 400 small block. Vigorously hoarded at one time, a few have appeared at the swap meet, and we even saw one at the junkyard not long ago. This prompted us to consider the ultimate budget tire-smoker when we received a scum-encrusted 400 small block from Hot Rod's David Freiburger. He swore it was good but abandoned it when he realized its value was declining faster than President Obama's approval rating. Other than the fact that it was a standard-bore block with stock parts, there was little to value in this casting. In fact, our theory is he found the 400 small block at the bottom of a deserted mine shaft under 100 feet of boric-acid-laced water, explaining why our block looked hideous even after a hot tank dunk. The Chevrolet gods demanded an exorcism, but we ignored 'em. Even after an abbreviated séance in which the ghost of Zora Arkus-Duntov threatened to cancel our lifetime membership in the Bow Tie cult, we pressed on. Those were valid warning signs. We decided to build a motor in a way that all good car crafters would understand-by hacking the budget with a blunt instrument. Sure, we took a risk by not boring the block and adding new pistons. The old pistons were in decent shape even after we beat them out of the block with a hammer! We even chose to ignore the serious rust pitting in the cylinder walls. We were not deterred.

We should have been, though, because the mechanical gods got the last laugh.

Our power plan was as simple as it was cheap. We liked the idea of enhancing the 400's strength of torque with a pair of Vortec iron heads and a budget flat-tappet cam to see how much grunt we could make. Then we'd pump the power with a set of large-port Vortec Bow Tie heads. So now that you know the backstory, we'll fast-forward to the assembly effort, dyno testing, and subsequent bloodletting.

Assembling the 400 Small Block
The smart move would have been to bore and torque-plate-hone the block. But since the push was to hit this short-block cheaply, we decided to stick with the game plan despite evidence of neglect. So this is our worst-case scenario. As you can see from the honing photo, there is power to be gained from doing the correct machine work by boring the block to eliminate the bore wear. We also kept to the bargain-basement plan with Summit's own cast-iron rings and basic bearings. We did have to grind the crank 0.010 inch undersize because there was metal transfer on the rod journals. Add in the cost of hot tanking, resizing the big ends of the rods, and installing cam bearings, and the machine shop cost alone came to roughly $400. Frankly, there's no way to really do this inexpensively. The days of the $1,000 V8 rebuild have gone the way of disco and Pac-Man.

Cam Specs
The cam we chose was the least expensive hydraulic flat-tappet cam and lifter set from Summit that also included a dual pattern to better support the Vortec's well-documented weak exhaust-port flow.

CAMSHAFT DURATION AT 0.050 LIFT LOBE SEPARATION
Summit hyd., intake 234 0.488 110
Exhaust 244 0.510

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68 comments
Michael Guirey
Michael Guirey

Hey Ford people...................Way to go Chevy ! # 1

Justin Patch
Justin Patch

I agree the torque numbers will never be outstanding, but our argument was about HP. Saying you could not get a 302 over 400hp with out power adders was just not correct.

Zachary Morris Fick
Zachary Morris Fick

If you guys are getting 450hp out of a iron an head ford 302 mine must be making 500hp.. which it's not it makes maybe 350hp.. it has Ed Curtis worked AFR 165 heads, F cam, 10:1 static, ported air gap 4bbl intake, and a Holley 650 w/ a 1" open spacer..

Robert Paul Holmstrom
Robert Paul Holmstrom

Crib stock rules...my 451 hp 302 had stock rods and crank...when we had it on the dyno, we went through 90 gallons of gas...pump gas, iron heads, went 11.13 at 121mph in a nearly stock 1990 Mustang the first time down the track...

Robert Paul Holmstrom
Robert Paul Holmstrom

In October of 1992, SuperFord did an article on one I built that made 451 hp that was a 302 on pump gas with iron heads.

Robert Paul Holmstrom
Robert Paul Holmstrom

With 302 cubes, don't expect 500 lb-ft without a blower or adder. Back in October of 1992, I built a pump gas Ford 302 with Iron Heads that made 451 HP at 7000 rpm, 368 lb-ft of torque and went 11.13 at 121 mph in a nearly stock 1990 notchback Mustang, the first pass down the track...we got thrown out by tech, given we only had a single hoop. Had a blow proff bell housing, c-clip eliminators, a drive shaft loop, 410 gear, and slicks...SuperFord did an article on the engine and called the article "Poor Man's Boss 302". After the ink, I built several copies after.

Peter Lehmann
Peter Lehmann

+1 Rob, it's all about torque and let's keep in mind this after all, is a no frills budget build that was salvaged junk.,. I doubt a 302 would even come close to those TQ numbers :)

Carl Stjernqvist
Carl Stjernqvist

Really, is this still news in 2014? Do it with some other makes, we see Chevs EVERYDAY!

Cam Beaton
Cam Beaton

You could do it with a Windsor, but you would need two of them.

Justin Patch
Justin Patch

Many a 302 has bested 400 HP with iron heads and no super charger or turbo. Who does your porting? Find someone else...

Donald Burley
Donald Burley

Still like the small block 400 over the big block 400

Jordan Nutt
Jordan Nutt

I read long time ago in Chevy high performance mag that the most power and torque they could get out of a vorteq headed small block was 500 lbs and 400 hp

Rickey Driskill
Rickey Driskill

@ Zachary . A Ford 302 will make 400up with iron heads. I have had one. 10to 1 compression. Nice beefy cam and with 2.02 1.60 valves in the heads. It will make it all day.

John Denker
John Denker

Alexander SkiourisPut this in the ranger

Zachary Morris Fick
Zachary Morris Fick

I'm not going to argue ... a Ford 302 won't make 400hp with iron heads with out boost..

Jesse DeGaro
Jesse DeGaro

Well that 400hp Ford did make that number as I bought the shortblock from Matt King who wrote the article and built the motor. He still has the cam and the heads that went with it and won't part with them. ;) I do agree not everything you read is true but some stuff is.

Kug Mag
Kug Mag

Two bolt, Vortex heads, and with all the accessories it makes that power all day long!!! With a little more aggressive top end will make close to if not 600 hp and torque and still be under $3,800 I'm loving this build...

Carroll Smith
Carroll Smith

why do these build ups go down the track ,minus 120 horsepower?,and are these numbers corrected air? 60 degrees zero humidity?AND NO MOPAR EVER SAW HEADERS like that except on a "RAIL" LOL

John Hinant
John Hinant

When you are done with it send it to me

Zachary Morris Fick
Zachary Morris Fick

Lol ya 400hp with an electric water pump and no accessories mounted just like the stock 87 Mustang 5.0 that made 400hp when it was closer to a 250hp motor..

Steven Bechler
Steven Bechler

Meanwhile a 50's Chrysler small block, will give you 650+ ft lbs!!!

Ken Howell
Ken Howell

Why does anyone use a chevrolet as that is french for crappy equipment.

Matt Derosia
Matt Derosia

think people search the globe for these blocks,

Matt Derosia
Matt Derosia

dream on 400,s got much more low end grunt than a 327 or a 350 why do you y

Jeff McMillan
Jeff McMillan

Why do people build 400 motors when there are much better and more reliable ones out there. My 327 could take this without breathing hard;)

Mark Glowacki
Mark Glowacki

Come on. It is tuff over here just to find a 400 let alone one that isn't cracked from freezing or way too expensive. We don't have any mines near me I can scavenge for one either. All the junkyards crushed everything when scrap was high back around 2008. I was hopin for the best with this article until I saw it was for a 400.

Lee Henderson
Lee Henderson

A 335series Ford 400 would DEMOLISH this thing with a budget build :D

Gunnar Larsson
Gunnar Larsson

I run with the same values on the camshaft the same pistons, 64cc combustion chambers 462 camel hump heads. but I've also run single turbo intercooler and 750 blowthru carburetor 6psi boost 32 degrees locked ignition. work well might be something for you to try on the car craft. I have tried with GTECH 0-60 4.2 sec engine sits in a 1964 impala

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