I'm curious about what kind of power streetable 400sbc's are making? I'm looking for real world setups and results. Also, how realistic is it to try and get a fuel injected (HSR) 400 sbc that makes 450+ hp to pass the sniffer? Just trying to compare/contrast a 400+hp buildup from a 355 and a 400 for a streetable car that will probably be driven 6 times a week in good weather. Thanks.


Brian

 

I used to have a '74 Camaro with a 406.

It had ported truck 400 heads, a Holley Contender single plane intake, Holley 750 DP, a Crane Fireball 302* .510" solid cam in front of a TH400 w/ 2800 stall TQ, and a 3.90:1 8.5" rear end.

It was my tire fryer. Even with those crappy heads (I bought it that way) it would still pull to 6500 no problemo. That engine had so much torque the white letters on the tires slowly turned into white walls. :sillylol:

That car was ALWAY spitting antifreeze. I purposely let the coolant level get low just so it would quit. That was after I tried a new radiator, new fan, lower T-Stat, new water pump, etc. After spending all that money I couldn't afford an overflow tank.

Streetable? Sure. That's where it spent all of it's life.
Daily driver? Hell no. That car would pass everything but a gas station.

Although I have to say I did drive it in the snow once. Damn Illinois weather. It was 68* earlier that day!!!

I suppose if you build it to be drivable you could swing it, but doesn't that defeat the purpose of building a 400 in the first place?

 

I've been getting real-world results off and on for at least 25 years with 400s in various of my cars. I don't know if that's long enough yet for me to claim that I really know anything about them though. Most recently was the one I had in my 83 car for about 12 years until I moved to California, and put the OE 305 (with a few subtle adjustments) back in it to pass inspection out there, rather than nutting the 400. It passed inspection where I was living before that (Tennessee, sniffer at idle, no dyno, no visual) with flying colors; and that was with a Comp XR282HR cam, a Holley 800 CFM carb, etc.

It's easy to make high power with more inches and pass inspection, than it is to make the same power with a smaller motor and pass inspection. You don't have to set the engine up for as high RPM operation if it's bigger, which means less cam, which means better manners at low speeds.

It's one hell of alot easier to get 400+ HP from a 400 than from a 350, whether the 350 is bored .030" or not.

This is all so obvious it almost hurts to have to come up with reasons why. "Does a 2-pound weight weigh more than a 1-pound weight? Prove your answer." Hmmmm......

 

My90Iroc,
How do you feel about Poweradders? Check out the polished Accel Superam set-up on Ebay (Item #2423471376) with the dual stage nitrous. The Superam set up alone has been used on many 400+ hp builds. IMHO, I say keep it tame at about 400 for driveability....and have your NOS when you need it. Why put up with a tempermental daily driver? Believe me...it gets old real fast! For years, I drove a Chevelle SS with a hot LS6 and after awhile it just was a pain.

 

See sig, and it get's 24+ mpg on the highway.

It's not bad, even w/the terrible heads and intake, and too-small headers.

 

I've built a few of them- all purely street motors. 13.0 @ 108-110 on street tires is like falling off a log whether you're using EFI or a carb setup. And I'm talking a REALLY small cam- 210* @ .050 with commonly available so-so heads. Get a little wilder with REALLY good heads and a hotter cam you'll be able to crank out some low 12s, still on street tires. With real traction any of thest times could drop by half a second.

 

im about done building my 400 to put in my 83 z28... im going with vortec heads, a dual pattern 214/224 @ .050 cam, and a simple air gap and 750 carb.... dyno2k gives this setup over 400 torque (flywheel) from idle to like 5000 rpm! with it peaking around 440... and horses peaking at about 380hp... i know those are flywheel numbers and dont know how much i can trust dyno2k, but looks like its gonna be a strong motor with a nice flat torque curve... also VERY streetable...

so if you're tihnking about a 400, go for it... it's worth it... (even if you have to pay for the short block... i got mine for free and it was rebuilt... dont ask... it helps when your dad owns an antique auto salvage
)

 

My IROC is daily driven. I purposely built it mild with that in mind, but even then, it is no slouch (see best time below). You can see everything the motor has on my website www.metzlerracing.com(too much to list).

With my modified TPI setup, I get better mileage than the old 305 (better power to weight ratio). I get about 15-16 in the city and 22 on the hwy, which is not great, but my higher stall converter has something to do with the lower numbers.

Since I live in Phoenix, the only issue I have is that the motor does not like stop-n-go traffic when the outside temp is over 105* (with A/C on). But then again, I only have a stock single row aluminum radiator and late model dual fan setup.

 

I've got 4 friends with 406's with MiniRams on them.
They all run in the low 12's to mid 11's.
The setup my friend had in his 87 GTA ran a best of 12.03 @124mph spinning all that way to the 660' mark.