Poncho article: SD VS HO, tribesman chime in:

Fhakya · #1 03-31-2006, 12:54 PM

I just received my July '06 issue of MCE and it had a dyno shootout (fairly stock specs) of a SD455 VS an 455HO w/ some compelling charts.

Have any of you 'tribesman' had similar experiences w/ the HO kicking-tail on the venerable SD?

I just skimmed the article so far but the dyno charts look interesting.

**njsteve** · #2 04-04-2006, 05:29 AM

Can you attach the article? Someone swiped my issue at the post office (again)

71-LS6 · #3 04-04-2006, 05:46 PM

I just skimmed over that article last night, the peak #'s on the HO were surprising and impressive @ 544 torque & 429 Hp. The SD came out pretty much where they thought it would @ 494 & 391. Jensen was definitely playing in his own yard, both engines produced those #'s in pure stock legal condition. That article gave me an unnatural craving for Pontiacs.

JLerum · #4 04-04-2006, 07:35 PM

I think the interesting thing is that the 429hp/544tq still only put the car at a 12.88 time. They were getting 1.96 to 2.02 times which are pretty good as well. Something isn't quite right. The car should go 3 or 4 tenths faster with that performance dynoed. I know Mark thinks the 3.90 gear replacing the 3.73 will give more performance but is it worth a couple of tenths? The dyno numbers are great but the performance in the car has yet to be had.

Jim

**PPPJJJFFF** · #5 04-04-2006, 10:43 PM

[ QUOTE ]
Can you attach the article? Someone swiped my issue at the post office (again)

[/ QUOTE ]

I 2nd that reuest!

Chevy454 · #6 04-05-2006, 02:51 PM

[ QUOTE ]
I think the interesting thing is that the 429hp/544tq still only put the car at a 12.88 time.

[/ QUOTE ]
I don't have my issue in front of me, but I know the S/S Poncho racers I've talked to are always sacrificing TQ to cheat the HP further up the rpm range...the higher powerband lets them take advantage of steeper gears...

JLerum · #7 04-05-2006, 04:41 PM

[ QUOTE ]
[ QUOTE ]
I think the interesting thing is that the 429hp/544tq still only put the car at a 12.88 time.

[/ QUOTE ]
I don't have my issue in front of me, but I know the S/S Poncho racers I've talked to are always sacrificing TQ to cheat the HP further up the rpm range...the higher powerband lets them take advantage of steeper gears...

[/ QUOTE ]

Not to bad mouth a GM product. Pontiacs are cool but McCarthey on the Super Stock website says Pontiacs make great torque but have issues with motor RPM acceleration. It can't get out of its own way after a certain point. Jack loves his Pontiacs but has that engineering Super Stock side of him.

JIM

yellowjudge · #8 04-06-2006, 08:37 AM

The 71/2 HO TAs are really the most overlooked cars in the hobby. Beef up the bottom end & you've got a great runner, or a hot date!!! HA

JLP · #9 04-07-2006, 10:44 AM

Nah, put that HO in the T-37. Always overlooked because of the dog dish hubcaps. Kinda like some of the COPO's. LOL. Course I am kinda prejudiced. Ya have to watch those dog dishes though, cause it usually means there is a mean dog around to bite you. And not in the rear.

tirebird · #10 04-08-2006, 11:19 PM

Those are tough numbers to believe are stock. In 71(2nd Gen), the Pontiac LS5 455HO was advt. as 335hp/480lbs tq. at the flywheel, pre-SAE adjusted numbers. All the magazine tests I read ran the cars in the 14's sometimes 13's. The best first generation cars, with Ram Air 1V L67 400 engines were easily in the 13's,..with some turning 12's.

Now, I know all the articles about my car said it was a high 13sec. car with the stock 71 LS5 455HO.

In 1973, the first LS2 455SD was offered, with lower c.r., then the HO(8:1 compared to 8.4:1), and was factory rated at 290hp/390tq.

One magazine test ran it at 13.54/104.2 in the quarter. Now, of course, all these engines were underated and the 73SD, I think, was the new SAE net hp. rating.

They were still fast cars. I'm just happy that Pontiac, in 1973, refused to sell the 2nd owner of my car, Tom Senter, an HD prompting Tom to call Berger to purchase an LS6 BBC warranty replacement engine for $750.

I don't know what the true hp/tq. of this engine is but Tom, with the "grand rodent" under the hood of the Tirebird, turned consistent 11's at 115. I'm too chicken to chance a catastrophic failure by trying to duplicate Tom's numbers at the track.