Opinions on a possible engine replacement

[77 K20]

I have another thread going about my irritating existing engine. Basically after re-doing the top end, it uses 1.5 quarts of oil and the radiator is down 3" in only 220 easy miles.

It is at the mechanic getting checked over, but I'm thinking it is untrustworthy junk now. (I often go 60+ miles in the middle of nowhere- don't need any problems).

It has a 400 right now, and I need more power for hills when I'm on the highway (but how much of this was from a somewhat tired bottom end?). Sometimes I'm pulling a trailer also. Highway RPM is 3,000.

I'm looking at 3 different engines from West Coast Engines. They have a 5 year warranty which will put my mind at ease a bit.

Option 1: 335hp, 375tq 350 with a RV roller camshaft. $1949
http://www.westcoastengines.com/Chevy-350-5-7-Roller-Engine-p/ch350s2.htm

Option 2: 375hp, 410tq 383 with a flat tappet RV cam $2495
http://www.westcoastengines.com/product-p/ch383s1.htm

Option 3: 405hp, 430tq 383 with a RV roller camshaft. $2895
http://www.westcoastengines.com/Chevy-383-Stroker-Stage-2-400-Horsepower-p/ch383s2.htm

There is an option 4 from another place. A remanufactured 400 with an RV cam (218/218), and pretty much everything else was stock. Claims 330hp 380tq. 5 year warranty also. $1865

Since a year or so I had a flat tappet camshaft go flat, I've read till my eyes fell out about zinc additive, and engine oils... and in someways I'd like a roller cam instead so I can forget all about zinc levels.

Option 1 has a nice cost to it, but I'm afraid I'd be disappointed on hills with this engine.

I've been bored at work for 2 days and have too many thoughts rattling around in my head about my truck. So thought I'd open a discussion to see what you guys thought.

It is not a daily driver. It is my work/play truck. I love chaining it fully up and going thru as deep of snow as I possibly can. I do mild rock crawling with it. I off road with it (at low speeds, not high speed desert stuff). I tow with it. Since it is an automatic I've had issues with 4 low and 1st gear wasn't low enough, the RPM would climb and the truck would "runaway". I'm thinking the higher compression of these engines would help with that a bit.

 

[rich weyand]

There are no dyno sheets on their pages that I can find, so there's no telling what these engines are doing. Could be great, could absolutely suck. Ask them if they can email you sample dyno sheets on these engines. Without knowing WHERE the torque comes in, it's pretty much impossible to make any conclusions about how well these engines will meet your needs.

You need high compression to make horsepower, but you don't need high compression to make torque. Horsepower (which basically measures torque at or above 5000 rpm) is worthless for your intended uses. Who cares? You gonna rock crawl or trailer tow or go play in the snow at 5000 rpm? Torque in the bottom is what matters.

I'm getting around 425 lbft of torque at 2500 rpm with a stock 350 crate engine and a cam change. That's with a dual-plane manifold, an Edelbrock carb, and Hooker headers. That whole setup is in the same price range you are talking, and it's a new engine, not a rebuilt one.

Warranties are worthless. The cost in time and effort and cash to pull a failed engine out and mail it back swamps the warranty claim. Getting something reliable to start with is the most important thing.

Finally, zinc for a flat-tappet engine is no big deal. They used to put enough in the oil for us, now you have to add it. After break-in, run Mobil1 10W30 with one bottle of ZDDPPlus. Done.

Anyway, that's my 2 cents. YMMV.

 

[MadOgre]

There are no dyno sheets on their pages that I can find, so there's no telling what these engines are doing. Could be great, could absolutely suck. Ask them if they can email you sample dyno sheets on these engines. Without knowing WHERE the torque comes in, it's pretty much impossible to make any conclusions about how well these engines will meet your needs.

You need high compression to make horsepower, but you don't need high compression to make torque. Horsepower (which basically measures torque at or above 5000 rpm) is worthless for your intended uses. Who cares? You gonna rock crawl or trailer tow or go play in the snow at 5000 rpm? Torque in the bottom is what matters.

I'm getting around 425 lbft of torque at 2500 rpm with a stock 350 crate engine and a cam change. That's with a dual-plane manifold, an Edelbrock carb, and Hooker headers. That whole setup is in the same price range you are talking, and it's a new engine, not a rebuilt one.

Warranties are worthless. The cost in time and effort and cash to pull a failed engine out and mail it back swamps the warranty claim. Getting something reliable to start with is the most important thing.

Finally, zinc for a flat-tappet engine is no big deal. They used to put enough in the oil for us, now you have to add it. After break-in, run Mobil1 10W30 with one bottle of ZDDPPlus. Done.

Anyway, that's my 2 cents. YMMV.

I agree. 350 lbs tourqe @ 3000 rpm is gonna be a more powerful engine to drive with then a 410 lbs tourqe @ 4500-5000. So it all depends on what rpms are needed to make the advertised power.

who cares about 5000 rpm unless you have a street rod.

you want in the 1500- 3500 rpm range

And yes your way better off spending a couple extra bucks if you have to and get a GM crate motor for reliability and warranty.

GMs motors are gonna make power in your rpm range right out of the box

 

[rich weyand]

I'd get the GM crate motor and change the cam right out of the box. You void the warranty, but those crate 350s are so bulletproof it's not really an issue to my mind.

A forum buddy (on a different forum) is doing that right now. GM crate 350/260, Edelbrock carb on 2101 manifold, Hooker 2453, and a Comp Cams 12-300-4. Other candidates: 12-235-2, 12-234-2. Those three cams are in increasing order of lift and horsepower, but (slightly) decreasing order of torque. All are high-torque cams though, delivering a torque curve that comes off idle around 300 lbft and is above 400 from 2500 to 4000.

Total cost including the carb, the manifold, the headers and the cam is in the 2000-2500 range.

 

[77 K20]

I emailed West Coast engines asking them to send dyno sheets on those engines. So far with my 2 square blazers and now 2 squarebody trucks I've never been lacking power at low speeds. If the need arises, I've had no problems with using 4 wheel low. But on all of them (3 of them were 400s) I've always needed more power on the highway. When I hit a steep pass I've always run out of steam in 3rd gear, then down shift to 2nd, and then not have much power with the engine roaring at 4000 RPM or so.

I can pull an engine out in a weekend, but don't like messing around with engines themselves. And unfortunately I've spent $1500 on my existing one that is no good. In all fairness I should have just bought a new engine to begin with, but didn't have the $$ at the time.

My dad went with the gm crate motor (350/290 hp) and changed out the cam. Not impressed. Very low compression. He said it is now great with new heads on it. I haven't driven it yet. Hopefully next weekend I can see how his square is.

Thanks for those cam numbers- I'll compare them against what I have now and what my dad has.

 

[rich weyand]

For higher compression heads, look at 12-238-2. It gives up too much dynamic compression for low-compression heads, but uses high compression heads well, based on the simulator.

On my 78 K10 with 3.73:1 and 31" BFGs, in third gear the fat part of the torque curve from 2500-3500 rpm is from 60-85. No downshifting there. The only reason to have to downshift is to get the rpms up because the engine is set up with the power up high in the rpm range. That is, the vehicle has horsepower up high and not torque down low.

As for your dad's situation, it depends on what he changed the cam out to. Most people go too big on a cam because they concentrate on horsepower, and hp does not matter in a driver. Only torque matters, and having it down low. Even the hot rod guys I know run marine cams for the torque.

You are concentrating on compression, but you don't need compression for torque.

 

[77 K20]

I wish I could have driven a 400 small block when it was brand new. Maybe all the ones I've had were too tired? Cause it was with them the only way to head up a pass was to downshift them. (and they were 100% stock)

My dad swapped out his cam for an Edelbrock 2102. 204*/214* .420"/442" lift 112* lobe separation

I do really like the torque curve on the GM 383HT, but don't understand why they are so expensive.

 

[rich weyand]

My dad swapped out his cam for an Edelbrock 2102. 204*/214* .420"/442" lift 112* lobe separation

The Edelbrock 2102 will actually reduce the bottom end torque of a stock 350/260 engine for more horsepower up top. It's also an old, slow grind (slow valve ramps), which makes the compromises more severe. Not a good choice. In a 350/290 engine, it will give you a little more in the bottom, but not much, at least not compared to the three cams I mentioned above.

The other one everybody on the net likes in the stock 350 is the XE268H (12-242-2), which gives up some bottom end torque (about 6%) for more hp on top (about 6%) compared to the 12-235-2, but it's still miles ahead of the 350/260, 350/290, or 350+2102 for torque in the driving rpm range.

Like I said, with the 3.73 gears, I am running around 420 lbft of torque in third gear from 60 to 85 mph with the 12-300-4 cam. The 350/290 makes about 280 lbft at 2500, so I have 50% more power available at 60 mph. The GM 350/260 gets maybe 350 lbft of torque. Even a Ram Jet 350 only gets about 380 lbft at 2500.

Of course, the 12-300-4 doesn't have the wind-up power in the 4000-5000 range -- even the 350/290 will beat it on horsepower above 4500 -- but that's debate points, not something you need for a street engine in a truck. WOT 2-3 shift point on my truck is around 60mph/3900 rpm (I modded the governor), which is perfect, because it takes me from the high end of the fattest part of the torque curve right back to the low end of the fattest part of the torque curve.

For pulling power in 3rd gear at cruising speed, you need the torque between 2500 and 3500 rpm (60-80 mph). With a horsepower oriented cam, you need to downshift up the hills and wind the engine up to where those horsepower numbers are because the torque just isn't there in the lower rpm range.

 

[Green79Scottsdale]

I would get the L31-R crate motor. Better compression compared to the 260hp/350ci motor (9.5:1 vs 8.4:1), better/more effecient heads (64cc Vortecs vs. 76cc "smoggers"), roller cam, 4-bolt mains, and 1-piece rear main seal. Slightly more $$, but in the grand scheme of things you might be happier.

 

[68post]

I would get the L31-R crate motor. Better compression compared to the 260hp/350ci motor (9.5:1 vs 8.4:1), better/more effecient heads (64cc Vortecs vs. 76cc "smoggers"), roller cam, 4-bolt mains, and 1-piece rear main seal. Slightly more $$, but in the grand scheme of things you might be happier.

That is the only affordable 350 crate engine to consider in my opinion.

But - any 350 will be noticeably down on torque compared to a 400. The only reason those 400's were down on power at 4,000 are the stock heads, (and the stock cam coming in a close second for poor performance).

I'll be installing a 400 in a work truck soon and will use my vortec heads and a cam that would be mild even in a 350. Shooting for peak torque around 3,000.

 

[77 K20]

So I looked at those cams, and the L31R. Seems the usual people I know are too busy in the summer and might be able to get it done by hunting season. I don't really want to do a shakedown test while out hunting.

Still can't get West Coast Engines to prove anything with a dyno chart. They keep telling me they will send one tomorrow. It has been a week now and even if they did email me one now how would I know it actually came from one of their engines?

I'm now thinking of ordering the HT383 from Chevrolet Performance. Some dynos I have seen of this didn't look impressive at all- but articles from Car Craft and things like them were impressive right out of the crate. Finally found the torque numbers people claimed these engines are good for:

http://paceperformance.com/attachment/34550-.pdf

380 ft/lbs at 1,500 RPM.
441 ft/lbs at 3,000 RPM (highway speeds)
400+ ft/lbs from 1800 RPM all the way to 4400 RPM

Jegs has the engine in stock. Can ship tomorrow. Free shipping. Didn't see anything about a core charge either- so I can keep my old engine for something.

 

[rich weyand]

The HT 383 is a nice motor, no question about it. Pricey, but nice right out of the box. Vortec heads, roller cam, ballsy as hell. What's not to like?

It's performance down low is perfect for your intended uses.

 

[77 K20]

It is more than I wanted to spend for sure... but I love my truck and have no plans to sell it. And with that I should be up and running soon so I can enjoy the end of summer and fall. Going to cost a bit in fuel to break it in.

Speaking of engine break in, it is a strange process. I found the GM paperwork online about the break in procedure. Something like drive it for 30 miles easily then do 5 medium acceleration runs up to 4,000 RPM then down to idle while in drive. Then do 2 at full throttle to 4,000 RPM then down to idle in drive. Then change the oil. Then drive 500 more miles without high RPM or stressing it (towing, etc).

Never heard of that before.

 

[77 K20]

Another thing I'm confused about in the GM setup instructions for their performance engines:

Set initial spark timing at 10º before top dead center (BTDC) at 650 rpm with the vacuum advance line to the
distributor disconnected and plugged. This setting will produce 32º of total advance at wide-open throttle (WOT).
The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using
only the internal centrifugal advance to achieve the correct timing curve.


Why would you disconnect and plug the vacuum advance? Thought this allowed the timing to advance more when cruising for better gas mileage.

 

[rich weyand]

It is more than I wanted to spend for sure... but I love my truck and have no plans to sell it. And with that I should be up and running soon so I can enjoy the end of summer and fall. Going to cost a bit in fuel to break it in.

Speaking of engine break in, it is a strange process. I found the GM paperwork online about the break in procedure. Something like drive it for 30 miles easily then do 5 medium acceleration runs up to 4,000 RPM then down to idle while in drive. Then do 2 at full throttle to 4,000 RPM then down to idle in drive. Then change the oil. Then drive 500 more miles without high RPM or stressing it (towing, etc).

Never heard of that before.

Very common back in the day. The first bit was done on new cars at the factory. The second bit was normal instructions for new cars. FWIW, I changed the oil again at 1500, then at 3000, then every 3000 after.

As for the money, you can save a couple grand and change by putting the 12-300-4 cam in a new 350/260 and get similar performance, but that won't be a roller engine and voids the warranty.