How much whp am I gonna have in my lifted truck

[Squarebody Rob]

I got a 79 Chevy k20 with a 6 inch lift with 37s, Im also running 4.10s...I have a 355 with aluminum heads(64cc), Holley 650 carb, edelbrock air gap intake, and weisco flat top pistons, rods and crank are stock... the engine has 10.0.1 compression, builder says it has 400hp to the crank

 

[bucket]

What cam and heads?

Going off the builder's estimate, I'm going to say 300 at the wheels, tops.

 

[shiftpro]

Tires too tall for the gear ratio..

 

[HotRodPC]

And what transmisison? That's a huge factor in figuring hp to the ground. With that much lift and tire size, I'm not real sure why it matters what the whp is. So long as it has enough power to pull a wet string out of a goats ass, and gets good traction to go where you want it to go, then it would be good with 100 whp. Sounds like a nice truck. If it ain't broke don't fix it. JMO

 

[HotRodPC]

What cam and heads?

Going off the builder's estimate, I'm going to say 300 at the wheels, tops.

With an auto trans, I'd agree 300 is at least in the ballpark with 400 to the crank.

 

[Ricko1966]

I use 20 percent loss through drive train as rule of thumb gross hp to net hp. So I'd say bucket is right in the ball park.

 

[Vbb199]

Probably 250 with 37's and 4.10s. I assume since its a k20, maybe it has a th400, with that 2.48 first gear, it'll help out that undergeared setup.

4.88, or 5.13 would probably return it to 300 at the tire
Thats my opinion.

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[bucket]

Probably 250 with 37's and 4.10s. I assume since its a k20, maybe it has a th400, with that 2.48 first gear, it'll help out that undergeared setup.

4.88, or 5.13 would probably return it to 300 at the tire
Thats my opinion.

You must be registered for see images attach

You could very well be right. 37's and 4:10's normally isn't a good combo and will suck away a lot of power.

 

[HotRodPC]

Probably 250 with 37's and 4.10s. I assume since its a k20, maybe it has a th400, with that 2.48 first gear, it'll help out that undergeared setup.

4.88, or 5.13 would probably return it to 300 at the tire
Thats my opinion.

You must be registered for see images attach

Don't forget to add 300-400rpm to your 1:1 ratio if an auto trans with non lock up converter.

 

[77 K20]

I'm not a fan of horsepower ratings on trucks or towing vehicles. Did he say how much torque? Any low end torque?

Unless you are planning on running it at a higher RPM where all your horsepower is, who cares?

I'm running 37s with 4.10s. The truck used to feel really quick with my 383 (444 ft/lbs) and 33s. Now with the 37s it still feels faster than stock with the 400 but not "quick". I still have more than enough power for hills at highway speed. Haven't towed my 5th wheel yet with these new tires...

And I thought that chart was the real actual physical size of the tire- not what is stamped on the sidewall. So you'd need to measure from the ground to the centerline of the hub then take that times two. A 37" will be 35"-36" depending on the tire. (unless you run 80 psi in them and there is zero tire squat).

With my 4.10s and an auto TH350 and lets say a 36" tire that puts me right in the middle of the green balanced power band.

 

[Squarebody Rob]

What cam and heads?

Going off the builder's estimate, I'm going to say 300 at the wheels, tops.

It’s got a Melling 22280 513/520 lift heads are liberty performance

 

[Squarebody Rob]

With an auto trans, I'd agree 300 is at least in the ballpark with 400 to the crank.

The trans is stock 700r4

 

[Squarebody Rob]

Probably 250 with 37's and 4.10s. I assume since its a k20, maybe it has a th400, with that 2.48 first gear, it'll help out that undergeared setup.

4.88, or 5.13 would probably return it to 300 at the tire
Thats my opinion.

You must be registered for see images attach

It’s got a stock 700r4

 

[Curt]

I rolled with with 37” with 4.10s.Probably right around same Hp with fastburn heads.I loved it.It went anywhere and pulled the ever living **** outta suckydutys and anything else stuck.

SM465 & Np205

 

[Dutch Rutter]

A stock 700r4 won't like moving those tires through those gears very well, much less with a bunch of power in front of it.. It sounds like you'll be wanting information/money for nv4500 swaps (easy-ish swap for an anchored 700r4) and possibly a gear change in your not so distant future.