My 1971 521

[mrbigtanker]

3 hours ago, d.p said:

Yeah the problem with that  1993 is so much done to it (that the seller paid to have done) that I am afraid that if I tried to undo it and swap it to something else it will turn into a headache.   Its got a Holley sniper efi and not even sure I want efi so having to undo all that for a traditional carb I could have a bad time.      

 

I am looking at this 69 with a 454 in it but only has 250HP...which is a snoozer if you ask me.  Dealership doesn't know what the engine came out of and not sure how they would even know it has 250HP without knowing what it came out of but who the fuck knows.  Chevy didn't introduce the 454 until 1970 so a mystery.  

 

 

Video: https://streamable.com/y6zluo

 

https://thunderroadautosales.com/listing/1969-chevrolet-c10/ 

Sounds more like a miss then a cam lope.

[datzenmike]

Torque is a static measurement. Horsepower is a measurement of torque over time and distance. 

 

If you torque a head bolt to 60 ft pounds and hold it, it remains 60 ft. lbs. and no work is done. If you maintain the 60 ft lbs but manage to turn the torque wrench at 500 RPM you can now calculate the HP from this. 60x500/5252=5.712 HP

 

If 1,000 RPMs then 60x1,000/5252= 11.42....Doubling the RPM at the same torque doubles the HP. This is why a flat torque curve is preferable. Each doubling of engine speed doubles the HP.

 

At 5,252 torque and HP are always equal.

Below 5,252 torque is always higher than HP

Above 5,252 HP is always higher than torque.

[d.p]

15 minutes ago, mrbigtanker said:

Sounds more like a miss then a cam lope.

 

Yeah that was my first impression as well,  almost like it was hunting or hesitating.

 

Per the dealer "its a 4-bolt main block with forged crank/rods/pistons, aluminum heads and .510/.540 roller cam with an Edelbrock 1411 performer 750 cfm carb and TH400 transmission."   I have been reading a lot and some people say a TH400 won't hold much power.  Seem like a lot of engine work for only 260HP?  

 

 

[Stoffregen Motorsports]

All of the big block Chevy trucks I've ever owned were great on top too. The best is the '96-'99 7.4L Vortec. Those motors spin to 6k and make power up top as well as torque down low.

 

Ray, I think I'd rather have a 396 than a 502. The bigger you go, the less they feel like usable daily drivers. Ok, I'd rather have a 427, but they never put those in trucks.

 

Years ago, there was an article in some engine builder magazine, where they tested "blueprinted" V8s from the '60s and '70s to see what kind of hp they really made, because most of the "published" numbers were low for insurance purposes. The big block Chevy 427 made over 500hp stock. The 427 Ford made over 600hp. I can't remember what the 426 Hemi made, but it was the most powerful of the bunch. I think I still have that magazine somewhere...

[mrbigtanker]

11 hours ago, Stoffregen Motorsports said:

All of the big block Chevy trucks I've ever owned were great on top too. The best is the '96-'99 7.4L Vortec. Those motors spin to 6k and make power up top as well as torque down low.

 

Ray, I think I'd rather have a 396 than a 502. The bigger you go, the less they feel like usable daily drivers. Ok, I'd rather have a 427, but they never put those in trucks.

 

Years ago, there was an article in some engine builder magazine, where they tested "blueprinted" V8s from the '60s and '70s to see what kind of hp they really made, because most of the "published" numbers were low for insurance purposes. The big block Chevy 427 made over 500hp stock. The 427 Ford made over 600hp. I can't remember what the 426 Hemi made, but it was the most powerful of the bunch. I think I still have that magazine somewhere...

Sounds about right except the Ford.lol

 

 

I agree, with the big blocks, I guess how much your going to drive it and for what, although it will be reliable just loud messy and heavy but fun. I guy once said I like the way old things look and the way new things work. So technology is a huge plus, if your just making a cool driver hauler truck sky is the limit, if your looking for sleeper in a sense and comfortable long hauls then go with the new stuff.

[d.p]

I think this time around I would want either old look with new tech or just new/new so that I don't have to mess with all or worry about breaking.  

[Stoffregen Motorsports]

Modern power is nice. But not all LS motors are NOT equal. Early Gen I through Gen III motors are getting hard to find, and they're all clapped out by now. They usually have issues with the cylinder delete stuff and the knock sensors. All of that can be deleted though. The cable throttle is nice too, as it makes for an easier swap. An early 4.8 or 5.3 will get 20 mpg or more if you try.

 

Later Gen IV with fly-by-wire throttle and cam sensors make tons more power than their same-size earlier counterparts, but the wiring is definitely more complex. Don't try any shortcuts on the sensors either. But, there are really only a few sensors to begin with. Air flow and temp, cam and crank position, MAP and O2. The FBW throttle is tunable so that's fun to play with. The mileage on the smaller LS motors is still good, but once you get into the 6.2 territory, you're getting 14 mpg, but you've also got 440hp, stock. 550hp is easy to get with a cam swap.

 

The best LS isn't an LS at all. It's the new(ish) LT based motors. Direct injection means more compression ratio and better horsepower and mileage. One caveat is that since they never came with a power steering pump, you'll need to adapt an aftermarket system.