Is this too much engine or just right for a K5 restoration.

[tjsblazer]

Guys I'm just starting to get in to my '72 K5 restoration. I'm gonna replace the very tired 350 with something a lot stronger. The vehicle will be a complete frame off resto and will be drivin only as a weekend cruiser but besides sounding cool, I definitely want it to be able to get up and go. It will be factory ride height with either 32 or 33 inch tires. Tranny transfer is the SM465 / NP205 combo and rear end gearing is probably going to be 3:54 (definitely not any taller as I don't like having it rev overly high at 65mph).

Motor:
402 small block (dart shp block)
I'm not going to get in to the engine specifics but a similar build dynoed at 495hp and 515 ft/lb torque.

I would really appreciate thoughts on this especially from those running higher horse engines on a similar drivetrain. Is this too much or just right.

[NW_Ryker]

It might just be me, but that seems like a lot of engine for a 4x4. Not that thats a bad thing, but if your gonna drop the big bucks on an engine, why not get a 2WD? And if you want get up and go, I don't know if a 465 will do it for you. I'm sure the truck you described would be pretty cool, but if it was me, Dropping that much into a 4x4 to go fast isn't worth it.

[old man jimmy]

I've added quite a few ponies to my 350. With the horses you're talking about, I hope you like rebuilding rear ends. I blew 3 with mine when I was younger. Then built a set of traction bars. You'll get an awful lot of spring rap up. I'm running an eaton posi with 3:73's. Another weak link is the drive line. Gone through more than my share of u joints, and a couple yolks. I know, you're probably thinking you won't get on it that hard. But if you've got it, you'll use it. Or their's no sense in having it. Just my thoughts. I was young once also.

[mustardjimmy71]

That motor sounds like a great way to find all your weak links. I think everyone will agree that when you have that much power and you break stuff, dont replace it, upgrade it! The 465/205 is a good combo but i think your gonna need axles and driveshafts that are more gooder.

[Mike C]

My opinion is that the SM465 dictates what you do power wise. The wide ratio nature of the trans wants a cam that peaks about 4500 rpm or so. In a 350 inch small block, that means something in the 210-212 deg duration at .050. In a 400 inch motor, stay less than 216.

My own experience with a big cam and the 4 speed is driveability SUCKED. The current Crane 266 (210 at .050) is awesome.

That Dart seems ideally suited to the car in your avatar while a 383 with the Crane 272 would be the bomb in the Blazer. And it should save you a bunch of $.

[AJs72K5]

I sure hope its not too much motor I've got a BBC 454 that specs out to 550HP and 580TQ sitting in my frame right now. But, I've also built the entire drivetrain to handle to motor.

[Firebirdjones]

I'm a speed junky so to me, making a 4x4 with power is fun.

The power your engine is rated at (flywheel) isn't all that radical for 400 cubes. The question is whether your stock manual trans will take it. I'd say no if you plan to hammer any gears. The U-joints in the driveline are small in these things compared to what I generally work with. So that's another issue.
The 12 bolt truck rears aren't bad, but they do have a rather small pinion diamter of 1.438 (whimpy) and I've snapped a couple of them screwing around on the street, so that's something else to watch for.

Otherwise, have at it

I dropped a LQ4 6.0 LS engine in mine and I'm now gearing up to install a Magneson blower and shooting for 10 lbs of boost to start.
This combo has made about 600 crank HP in other cars with this engine, and generally about 500 RWHP and similar torque.
Since I'm pushing through an NP205 transfer case and turning over 33" tires, I suspect a bit less at the wheels (we'll see). Still enough to raise some eyebrows on the street

I had built a Jeep Scrambler in the past with a 96 LT1/4L60E combo and 4.10 gears with 33's, it was an absolute blast to drive and whooped many street cars with that thing Nothing funnier than the looks on peoples faces after a little redlight action I had more fun in that thing than my BBC chevelle.

Keep in mind these 4x4 blazers are heavy. Mine weighs 4,600 lbs. without me in it. So I'm concentrating on torque right off idle more than anything, hence the Magneson. But the heavy weight also translates to broken parts when pushed.