Turn Key crate engine swap questions

[CO2GURU]

Im looking into doing a engine swap in my 77c10.  I currently have a stock 350 that only has 24,000 miles on it. I would like to keep that motor as stock as possible, so im thinking about pulling it out and buying a turn key crate 350.  I would like to only spend around 5K but im willing to spend more if I really need to.  I will probably keep the th350 tranny.  so what motor or supplier do yall recommend.  Looking for something with over 350HP.  I just bought a 600 cfm edelbrock (hoping i can re-use that???) and i already have a set of long headers. so lets hear it, what would yall go with?

[Jason S]

I've had the GM Performance Parts 300 hp 350HO in my '73 for 17 or 18 years now it has been very reliable and strong for well over 100,000 miles. It was all new, had a warranty and good power.  I think the current version offered is now rated at 330 hp.  My engine was purchased through a Chevy dealer for about $2200 then (though I also had a dealer discount). It was and still is a bit pricey, but I have no regrets for it. Mine was just the longblock with the sheetmetal. I had to add the water pump, balancer, flexplate, intake, distributor, etc.

It will be a very difficult decision whenever I do something with this engine.  It's been a very good engine, the only thing I would consider replacing it with is another 350HO or a 383...

If you went with the 350HO, Jegs offers several levels of the engine with various amount of additional parts with prices ranging from $3,000 to $5,000 including shipping. Your carb will be fine for that engine.

[CO2GURU]

here is one I found. little more than 5K but its a turn key engine with 400HP

http://www.jegs.com/i/Chevrolet-Performance/809/19301294K/10002/-1

are these things dyno tested or are they estimating 400HP?

[Jason S]

Mine had never been run. It came with a spec sheet that listed the parts (headers, carb, distributor, etc.) that produced 300 hp. 

I'm pretty sure that one (or several) engines are assembled and dyno'd to prove the hp/tq numbers and then engines are assembled using that particular combination of parts.
 
I couldn't get the pdf of the dyno results to open, but I'd suspect that the peak numbers are pretty high up on the rpm band; which may be something to consider before you plunk down a bunch of cash.

[CO2GURU]

Mine had never been run. It came with a spec sheet that listed the parts (headers, carb, distributor, etc.) that produced 300 hp. 

I'm pretty sure that one (or several) engines are assembled and dyno'd to prove the hp/tq numbers and then engines are assembled using that particular combination of parts.
 
I couldn't get the pdf of the dyno results to open, but I'd suspect that the peak numbers are pretty high up on the rpm band; which may be something to consider before you plunk down a bunch of cash.

peak TQ is at 4000 rpm and HP is around 5700

see if this attachment works

[CO2GURU]

keep in mind this will be a every other sunday truck. very low miles.

[Jason S]

Peak numbers (especially hp) occur high on the rpm band, but the engine should certainly be able to turn that high.

If you were to go with that engine, my suggestion would be to consider the condition of the transmission, torque convertor stall speed and final drive ratio (rear end gearing).  It'd be quite a bit of engine for a Sunday driver... 


Others may have some crate options to offer up too...

[rich weyand]

You're speccing it wrong, IMO.  On the street, horsepower doesn't matter.  Torque is what you drive.  And a torque peak at 4000 rpm is poorly placed for a truck.  Car, too, for that matter.

I only have 285 hp, but 420+ lbft of torque at 2500 rpm.  Compare that to the torque curve above, which is maybe 350 lbft at 2500 and never gets above 400.

Get a stock 350/260hp crate engine and put a 12-238-2 cam and DART heads on it.  That'll get you 400 hp @5500 and 420+ lbft of torque flat from 2250 to 5000 rpm.