81LT4

has anyone done this,and if so, was it worth the build.
I would like to build a 400small block with vortec heads
and TPI induction. I know a 400 has plenty torq, but will it be
over kill useing a tpi set up, as they give lots of torqe also.

eric305TPI

The problem with the TPI on the 400 is that it will probably fall on its face after 4K+/- some RPM. As you mentioned it will work great for torque.

Vader

TPI runners will probably be painfully restrictive on a 400 inch engine. You might make really good torque at very low RPMs, but power will fall off even faster (lower RPM) than most other TPI installations.

81LT4

So what was the purpose of the 400 sb?????
I guess there only great for carb style. If im
correct, the 400 needs lots of air to perform well
and the tpi does not help there.

eric305TPI

Stick a HSR or comparable intake on it with the right other parts(heads and valvetrain) and its a fun little engine.
Or stick a carb and matching intake on it.

Chris89GTA

iTrader: (2)

What do you mean what was the point of the SBC 400?? Not trying to be a dick, just asking. The purpose was to have more cubes than a SBC 350 I guess. Its just what it is. There was never a production 400 w/ TPI. The TPI was really designed for a motor more like a 305 from what I understand. It did alright on the 350, but it could still benefit from major intake mods.

A short runner FI setup on a 400 if you want to stay FI is the way to go. Something like a miniram, stealth ram or LT1 intake would feed it. A lot of guys run the carb though, b/c you can get a carb matched to what you need air wise for that big cubed motor...

81LT4

When I said what was the purpose, I meant what were they used
in. I know they never made a TPI 400, cause production stoped in
the seventies im sure. you never really hear of a 400 build up!
whats the purpose of a 400? a good HP motor? really more
of a torqe motor? WHAT IS GOOD FROM A 400 to use it for.
350's are super commonly used.

Air_Adam

The 400 wasn't every really meant to be a performance engine by GM. Most of them had around 8:1 compression, low-rise cast iron intake, 2bbl carb... in short, they were lame.

They do have great potential though, but not with TPI. With a TPI manifold, you'd make ungodly torque, but it would just hit a brick wall around 4000 rpm.

If you really wanna get the most out of it, you gotta use either a 4bbl carb, or an aftermarket EFI setup like a Stealth Ram or a Super Ram.

The 400, if built with the right induction system (ie. not TPI), can make huge amounts of HP and torque, and in a very streetable package too. There are quite a few 400s on this board making 400+hp and they are driven every day.

If you are looking for a 400, the best place to look (so i hear) are the '70s land yacts like Impalas, as well as trucks.

Confuzed1

iTrader: (4)

I agree with Air_Adam - 400 was a smogger engine mainly for torque on large cars. They came in Caprices, trucks etc...

I just dropped my 400 in a few days ago. It dynoed at 490 ftlbs. at 3400 rpm's....with a carb. Hoping to have it running in a week or so.

TPI would choke it I think, unless you could hog out the ports somehow.....but then it wouldn't be "tuned" port injection anymore!!

81LT4

I have one from an Impala, just want to do somthing with it.
I was hopeing fuel injection wise. I like how the TPI is not
so tall.

Riley's35089rs+

and the 76-78 caprice!

Ricktpi

1976 was the last year the 400 was used in the B body (Caprice/Impala). 1979 was the last year for trucks.

Riley's35089rs+

oops..sorry..mine is a 76 ..

MrDude_1

my uncle has TPI on two 400 engines.


i dont know where you guys are getting 4000 from.... it runs out of air around 2800 and falls totally on its face past 32..... if you wing it out to 4k to shift you would go slower in the 1/4


in short, it just doesnt flow enough air.

now a stealthram, LT1 intake or one of the other short runner/high flow setups work great.

Z28GEN3

theres a guy on here by the name aziroc on the SW board whos got a 400 sbc with 399rwhp/436rwtq and a 200 shot using a TPI delivery system. its a good 12 sec car. if built properly a TPI system should perform good.

MrDude_1

so he made a 12 second motor out of a 11 second motor? that doesnt seem right.

five7kid

iTrader: (14)

400 with EFI should be HSR or Miniram, in my little ol' mind.

OMINOUS_87

Dont forget the Superram!!!

81LT4

I talked to terry at TPIS, and he said a miniram would
do the job well, and has plenty of torqe and hp for this size motor.
He also said, the miniram would let the 400 breath very well.

Confuzed1

iTrader: (4)

Yeah, I'd buy that. Your original question stated TPI, not a miniram....

81LT4

It was about the TPI, I wanted to use it cause i
already have one. Looks like for the 400, I would have to
go with the mini ram, according to TPIS.

MrDude_1

thats because they make their higher-priced-then-gold miniram that they want to sell.

yes it will work great... but you have other options.

modified LT1 intake,and holley stealth ram are the first two to come to mind.

81LT4

DUDE, yes you are right, after I thought about it, for
$1200.00 with the rails, that is just to high for an intake.
A carb and intake would be way cheaper, with
the same or better performance. THANKS FOR ALL THE INPUT

406TPI

iTrader: (1)

I HAD a 400 with TPI. I put on a super ram base SLP siamesed runners and a 58mm TB.....everything was ported to the max....the car completely fell on it's face at 4500rpm. Kinda disapponting...but being able to light both tires up at 40mph in 3rd gear was kinda neat.

Dr G

If you don't mind me asking, what intake are you running now? LT1, miniram, Holley stealth ram? Did you go carbed?

400Z28Racer

iTrader: (4)

John Lingenfelter (RIP) made a killer 420. 3.875 stroke, 5.875 rods, custom pistons, 234/244 cam, 190 AFR ported heads and Superram on the top. This engine made 540 tq @ 4500 and 525 hp @ 5500.

comatose 88 WS6

dayum, that sounds like a sick motor to build.

TB_91_GTA

Would putting a supercharger in front of the TPI help to give it enough air??

MrDude_1

sure.

but you would still get even more power with a diffrent manifold.

TB_91_GTA

you mean supercharger with a miniram or stealthram, and not just a different manifold without the supercharger, right?