"Legendary Smallblock Shootout"

[Joe C.]

There is an interesting article appearing in the September issue of "Super Chevy" magazine, which dyno tests the DZ (Z28-302) versus the 1964-'65 L76 (30-30 equipped 327) versus the LT1 (both versions: 1970 with closed chambered heads, and the 1971-72 smog version with open chambered heads).
The test is not very scientific, the results are flawed, and there is at least ONE major error in the stated original configuration of the L76 (can you find it?).
SOME of the results will surprise you; keep in mind that this is NOT an "apples-to-apples" comparison.

Joe

[Stuart F.]

Re: "Legendary Smallblock Shootout"

Joe;

I have that issue and skimmed over the article once, but will go back and check it carefully. If there are any errors, it is obvious they didn't let Doug Marion proof it.

Stu Fox

[Gene M.]

Re: "Legendary Smallblock Shootout"

The small block shoot out has not much in common with the original Corvette engines. The rod lengths are wrong and thus the pistons are not correct. This comparison is just a wish and nothing more. Why didn't they use real GM engines as they were built? Heavens there are enough around with out making up fake clones.

Every little thing that was deviated from the original detracts from real out come results on the dyno

Sad............

[Joe C.]

Re: "Legendary Smallblock Shootout"

The small block shoot out has not much in common with the original Corvette engines. The rod lengths are wrong and thus the pistons are not correct. This comparison is just a wish and nothing more. Why didn't they use real GM engines as they were built? Heavens there are enough around with out making up fake clones.

Every little thing that was deviated from the original detracts from real out come results on the dyno

Sad............

True, Gene.

All the parts that they said were NOT available......ARE. Especially the pistons, with proper comp heights so as to use the proper 5.7" rods. L76 pistons are available in olde fashioned, crappy boat anchor form from Federal Mogul if you don't want to buy the better ones from SRP. I have seen the LT1 pistons, too. The Z pistons are for sure available from SRP, but not sure if available in boat anchor form from FM.

Why the hell did they put electric fans on them?
Why the hell did they load down the engines with HIGH VOLUME oil pumps!!!!!!!
Why did they use 1 3/4" primary tube headers instead of 1 5/8" ................especially since they were only winding them to less than 7 grand. Cost them some torque.

There are many more obvious faults with their analysis, plus a couple that I'd be willing to bet that nobody thinks of. These couple are by far the most important.

Joe

[John M.]

Re: "Legendary Smallblock Shootout"

So what were the results?

[Joe C.]

Re: "Legendary Smallblock Shootout"

So what were the results?

Here it is:

[John M.]

Re: "Legendary Smallblock Shootout"

I'm excited to get mine on the road and see how she feels.

I have a 69 350/350 but was built with a 383 Stroker Kit and all the internal goodies.

On the exterior however, it's bone stock, numbers correct. Smog an all.

Dyno'ed at 400HP, but more impressive was the torque at 460 Ft. Lbs.

I can't wait to see how that snaps my head back on a launch.

[Clark K.]

Re: "Legendary Smallblock Shootout"

Since I own a 1965 L76 A/C coupe, I was very interested in the "Legendary Small-Block Shootout" story. Personally, I cannot stand this type of "hot rod" magazine but I ran out and bought the Sept. issue of Super Chevy magazine today. I wanted to know what the argument was. Ok, I understand the errors the writers/testers made, including the wrong exhaust manifolds and carbs. The testers were up front about the changes. So they tried, which is more than most people can say. I think the dyno test is great since it DOES compare these three great engines, the Z/28 (302/295hp), the L76 (327/365hp), and the 1970 LT-1 (350/370hp).

Here are the results for those who do not wish to buy the magazine:

Z/28 (302) - 356 hp @ 6500 rpm 332 lb/ft @ 4300 rpm

L76 (327) - 352 hp @ 6300 rpm 363 lb/ft @ 4300 rpm

1970 LT-1 (350) - 353 hp @ 5500 rpm 391 lb/ft @ 3800 rpm

The winner was none of the above. They also tested the 1971 smog-motor LT-1: This engine has a lower (9:1) compression ratio but beat the others: 362 hp @ 5800 rpm 382 lb/ft @ 4000 rpm

This is a big surprise which I am having trouble understanding. Lower compression, everything else the same, and higher peak hp? The testers credited the "487 heads" on this engine. Go figure. -Clark

[Michael F.]

Re: "Legendary Smallblock Shootout"

bozos set up and performed the article, no where near reality, trash like that annoys me greatly

[Stuart F.]

Re: "Legendary Smallblock Shootout"

Well, all you great NCRS experts, wouldn't it be nice to have the Super Chevy writers respond to your criticisms? I'd love to view that brew ha ha! Course that will never happen, but it's always fun to watch big egos clash. Has any one considered writing or calling them and taking them to task? or is it just easier to sit back in the protected limited access of this discussion board and take pot shots at their efforts? The reason this interests me so is that it was someone at Super Chevy that told me "No, you don't have 461X heads on your 63 L-76"!

Stu Fox

[Joe C.]

Re: "Legendary Smallblock Shootout"

Since I own a 1965 L76 A/C coupe, I was very interested in the "Legendary Small-Block Shootout" story. Personally, I cannot stand this type of "hot rod" magazine but I ran out and bought the Sept. issue of Super Chevy magazine today. I wanted to know what the argument was. Ok, I understand the errors the writers/testers made, including the wrong exhaust manifolds and carbs. The testers were up front about the changes. So they tried, which is more than most people can say. I think the dyno test is great since it DOES compare these three great engines, the Z/28 (302/295hp), the L76 (327/365hp), and the 1970 LT-1 (350/370hp).

Here are the results for those who do not wish to buy the magazine:

Z/28 (302) - 356 hp @ 6500 rpm 332 lb/ft @ 4300 rpm

L76 (327) - 352 hp @ 6300 rpm 363 lb/ft @ 4300 rpm

1970 LT-1 (350) - 353 hp @ 5500 rpm 391 lb/ft @ 3800 rpm

The winner was none of the above. They also tested the 1971 smog-motor LT-1: This engine has a lower (9:1) compression ratio but beat the others: 362 hp @ 5800 rpm 382 lb/ft @ 4000 rpm

This is a big surprise which I am having trouble understanding. Lower compression, everything else the same, and higher peak hp? The testers credited the "487 heads" on this engine. Go figure. -Clark

Clark,

That particular result is not surprising. The open chambered heads flow better than the closed chambered heads, and if you look at the article's "results" page, which I posted above, you'll see it. The reason that they flow better is because the valves are not as shrouded (there is more clearance to the chamber wall on the spark plug side) as those in a closed chambered head, thereby providing a closer to ideal (at least: valve diameter/4) amount of clearance. Back in the "old days", open chambered heads were sought after by racers, BUT, the increase in chamber volume was made up for with thinner head gaskets and/or larger piston domes.

What I find most disturbing about the article, in addition to what I stated in a post above, was the fact that the author stated that the L76 was originally equipped with a 780 cfm carb. The fact is that it was originally equipped with a 585 cfm Holley. Its original equipment 461 intake was also much more restrictive than the Z28 intake used for the test. The use of the bigger carb and bigger intake on the L76 should have resulted in higher power and torque numbers than those shown in the article. There was something else lacking in the L76 build which sapped it of power. A healthy and properly built factory configured L76 should make peak torque in the neighborhood of 4600-4800 RPM; the test engine signed off early at 4300 RPM. The modified L76 with the big intake and carb should have carried that near peak torque higher into the rev range, and so should have made substantially more power than a stock L76. So, the test L76 obviously had a problem, and it might have been caused by a myriad of things, including: ring gaps, cylinder wall flex, cylinder head core shift, cam timing, mixture, ignition timing, cam specification (cam spec not matching that stated on the carton), and more.

Joe

[Gene M.]

Re: "Legendary Smallblock Shootout"

Stu,
I and probably most of the guys on this NCRS web page could care less what Super Chevy thinks of our discussion of their magazine. We are just sharing among ourselves the thoughts we have on the engine comparisons.

I have in the past written to various magazines but never got any response. So now I don't.

We don't need "safety of this web site" to share thoughts. I think most guys on it say what they want.
Gene

[Joe C.]

Re: "Legendary Smallblock Shootout"

Stu,
I and probably most of the guys on this NCRS web page could care less what Super Chevy thinks of our discussion of their magazine. We are just sharing among ourselves the thoughts we have on the engine comparisons.

I have in the past written to various magazines but never got any response. So now I don't.

We don't need "safety of this web site" to share thoughts. I think most guys on it say what they want.
Gene

I would not write to them.

Not out of "fear", but out of futility.

Why should I waste my time and effort in order to protest a tech article that was written "creatively". Much license was used in order to stir controversy.

The article was obviously skewed and sloppily edited....................AND..............leaves an opening for "follow-up" articles in order to "fine tune" (correct) the results.

The offensive part of the article is that it has trashed probably the best power maker of the foursome.

Circulate a signed petition on behalf of the "offended parties" who participate in the NCRS TDB, and I'll write a cover letter showing anyone's displeasure.

Joe

[Gene M.]

Re: "Legendary Smallblock Shootout"

Joe,
Sounds good to me, but I think you would be wasting your time as I think Super Chevy could care less. Most of their readers don't have a clue of what the "real" old engines were.
Gene

[Wayne M.]

Re: "Legendary Smallblock Shootout"

Joe,
Sounds good to me, but I think you would be wasting your time as I think Super Chevy could care less. Most of their readers don't have a clue of what the "real" old engines were.
Gene

Gene -- you may remember a comparison test, strictly among brand new 1969 Corvettes , that was in the July 1969 issue of Car Life magazine. Billed as "every body style; every engine; every transmission; every rear ratio; every major accessory". Article is 16 pages long. Although the LT1 wasn't released yet, the specs and components were available, so they built one for a total of 3 small blocks tested (ZQ3, L46, LT1), and five big blocks (L36, L68, L71, L89, L88). Acceleration curves provided.