Hi all.

I was looking on the internet and in the Scoggin-Dickie catalog for a motor for my Camaro (which will see mostly street use and light drag duty) and I have a few Q's?

I am looking at the 330hp/350 motor, are the hp ratings that GM claiims for their crate motors factual?

Is there any under/overrating the numbers on their part?

 

The ZZ4 with the fast burn heads is AWESOME!!!!!!!!! It does all it rated and a little more. Their numbers are pretty close

 

I would get the 330hp 350 or a 383ht I you wanted a crate motor and wait till the warrenty is out and swap cams if you want more power.I have the zz4 and it is a great motor but I would just get the 330ho if I did it all over again. From what I have seen the 350HO might be underated and I know for a fact on the engine dyno that I have seen a zz4 with everything gm says and the most I have every seen is 348hp.The zz4 is known for not putting out the numbers they say.The most I have ever seen at the rear wheels is 281rwhp with a stick. I dynoed at 271rwhp and 368rwtq with a 700r4. I have smaller 1 5/8 instead of 1 3/4 headers but a 1 3/4 true dual header is to much for a street driven motor like the zz4 in my opinion.I also have 1.5 rollers that might add 3-5hp but it is otherwise stock. The 1 3/4 are worth about 10hp on a carbed zz4 and they lose 30-40 ftlbs of torque which is not worth it in my opinion.The only reason the 330ho makes a little less power is the cam and compression. The 350ho heads are vortec and far superior. The only thing is the bottom end of the zz4 is stronger but for the amount of money a zz4 costs you could build a wicked 383 stroker from your local machine shop.When I bought mine 6 years ago it was 3200 and know I think they run around 4000 which is starting to get a little over inflated in my opinion.

 

I'm quite content with my 350/33HO, which is a barrelful of fun compared to my old modded LG4. I purchased mine from Jeg's, by the way (Cheapest price I could find at the time).

JamesC

 

get the 383 with afr heads, u might not think u want the power now but in acouple months i know you will

 

It's not over/underrating, but a different rating system. The numbers you see for our stock engines are net flywheel ratings, meaning running the engine on the dyno with the equipment it would have installed in the actual engine bay - air cleaner, induction and ignition systems, water & fuel pumps, alternator, and full exhaust & emissions systems installed and operating. Those are very realistic numbers that can be used to compare different vehicle models apples-to-apples.

The crate motor numbers are gross flywheel ratings - the best carb and induction system they can match to the engine regardless of what you use, a velocity stack on the carb instead of an air cleaner, electric water pump, open long tube headers, fuel and electrical power supplied by the dyno facility and not the engine, etc. They'll even go so far as to use different induction systems to get the highest possible torque with one and HP numbers with the other. Those numbers are typically much higher than the net numbers, and can be even farther off depending upon how "bad" your combo is put together - the 330HP engine may put out a higher percentage of that rated HP than the 383 would with the same carb and intake you use, for instance.

 

five7kid,

So then the ratings on crate motors are just like weight-loss infomercials with the typical "your results may vary" disclaimers. So then instead of testing with proper exhaust, basic intake and carb, they are probably using hi-po intakes, carbs, and open exhausts, that may or may not be attainable by the public, to fudge the numbers if I am following you correctly?

 

I wouldn't say they use parts that aren't available to the public. However, the numbers don't realistically represent the power the engine will make installed. But, since these are crate engines, to try to cover all of the potential combos customers would use would be impossible. So, the numbers are "real", but not representative of what will happen in your car.

The factory used to rate all of their engines that way - 300 horse 350, 409 horse 409, etc.

In days past, the factory had a kit to install the ZZ4 into carbureted 3rd gens - the ZZ4 is rated at 355 HP, as installed with the kit it was more like 300. Still a big jump from the best L98's 240 net HP. That's what you need to keep in mind when you look at crate HP #'s.

 

Another question. Which is better in term of value, buying a crate motor or building an engine from scratch (good junkyard block w/hi-po parts?) Does anyone recommend any books/literature on building one.

 

Each has its advantages. With the crate engine, you don't have to worry about a bad core, and will probably have a warranty. Building up a core will probably involve changing out heads, and will take more time. You'll probably compromise on things like crank and rods, just because that's what the core had in it. You could replace those things with aftermarket, but then you're getting up to the crate cost even before you get it assembled. You know without a doubt what you've got in what you build. However, if you've never built one before, you could get something wrong and ruin the engine before you ever drive it. On the other hand, you'll learn more and have more respect for what you build than what you buy (typically).