pls help with classification math

stage1scott · 01-05-2008, 09:40 PM

in another thread
http://classracer.com/classforum/showthread.php?t=8643

I made an offhand coment about weight of the 72 G/SA Buick shown for sale on the ebay listing. the car has semingly substantial weight addition capabilities, noted by another poster, and having owned several of these cars (no stock/superstockers, just street and bracket raced vehicles) I am pretty familiar with what they weigh, so I got to wondering and then researching where this car actually falls in NHRA rules. According to NHRA Classification guide, if I am reading it right for 72 GS 455, (and I readily admit to knowing ittle about how it actually works,except apparently If someone could get a letter from carrol shelby they could do whatever they want) this engine carries a hp factor of 330 and the weight classification of 10.97, making it an E/SA at best, with a 3620 required weight, and if I understand it, you could add a little weight and drop to F/SA, how would it get into G????

Tony Janes · 01-05-2008, 09:48 PM

10.00 is a natural E Car, the break is 10.97 which makes it a natural F car. So it can run E,F,or G/SA by rule

stage1scott · 01-05-2008, 09:58 PM

thank you tony, apparently I did not understand the breaks, and thought it was a natural E car. Then you can remove weight and go up to E, or add to go down to G-think I get it now!! Thanks again!

Johnny U · 01-06-2008, 05:03 PM

Stage1scott to further clarify the classification, to run the Buick in g/sa the min. weight with driver would be 3800lbs. Multiply 11 (G factor) by 330 (rated HP) and add 170 for driver. I have a 71 GS that I ran in G/SA and I had to add weight to achieve 3800. When I ran it in F/SA a few years back I could just barely get it to mimimun weight and that was when the HP rating was at 335(I think it came down in 2002). This past year I ran SS/LA with the stocker motor and my min weight was 3875 and I had about 240 lbs of extra weight added to make the min weight. Hope this helps some.

stage1scott · 01-06-2008, 05:58 PM

hey Johnny, thanks that helps even further. and makes me see the reason for a weight box. My low 13 second street car (72, a/c,cruise, drag radials) weighed 4138 with me in it (190 lbs) and a half tank at fontana in november, so I could see 3400 lbs in an "empty" race car, although it would take some weight loss concentration to get to D wieght in a 70, I guess. what rear ratio does it take to move these things competitively? at these weights? and also, since my interest is now all over the place, what cyl heads are you allowed in SS? still the cast iron heads, with small valves for the non-stage 1 engine?? but any camshaft/rockers?? thanks for the info in advance, I am always stunned at how fast legal NHRA stock and super stockers are these days, and a being a Buick owner/enthusiast, am interested in how these cars are running in the curent rules structure. Someone over on V8 Buick.com told me Jason line's old car is in the pacific northwest, D/SA, has run some 10.40s!!! that is just amazing to me!

Johnny U · 01-06-2008, 09:47 PM

I use a 4.30 gear in my stocker/ss car. Also a 2.75 low gear in the trans helps immensely to get the car off the line but with the 4.30 rear it keeps the trap rpm around 6000 to 6200 rpm. I believe that Jasons old car is now owned by Alf Wiebe and I heard that that thing has been in the low 10.30s if im not mistaken. In SS you have to use the cast iron heads for the year that you claim, small valve if you use the 330 hp motor or you can use the stage one size valves but the HP rating is higher and it will put you up 2 classes at approx. the same weight. Talk to you later.

01-05-2008, 09:40 PM	#1
stage1scott Member Join Date: Dec 2003 Location: Cornville Posts: 406 Likes: 1,870 Liked 108 Times in 44 Posts	pls help with classification math in another thread http://classracer.com/classforum/showthread.php?t=8643 I made an offhand coment about weight of the 72 G/SA Buick shown for sale on the ebay listing. the car has semingly substantial weight addition capabilities, noted by another poster, and having owned several of these cars (no stock/superstockers, just street and bracket raced vehicles) I am pretty familiar with what they weigh, so I got to wondering and then researching where this car actually falls in NHRA rules. According to NHRA Classification guide, if I am reading it right for 72 GS 455, (and I readily admit to knowing ittle about how it actually works,except apparently If someone could get a letter from carrol shelby they could do whatever they want) this engine carries a hp factor of 330 and the weight classification of 10.97, making it an E/SA at best, with a 3620 required weight, and if I understand it, you could add a little weight and drop to F/SA, how would it get into G????

01-05-2008, 09:48 PM	#2
Tony Janes Senior Member Join Date: Jan 2002 Location: Whittier, Ca Posts: 830 Likes: 77 Liked 3 Times in 3 Posts	Re: pls help with classification math 10.00 is a natural E Car, the break is 10.97 which makes it a natural F car. So it can run E,F,or G/SA by rule __________________ Tony Janes 7941 STK, SS

01-05-2008, 09:58 PM	#3
stage1scott Member Join Date: Dec 2003 Location: Cornville Posts: 406 Likes: 1,870 Liked 108 Times in 44 Posts	Re: pls help with classification math thank you tony, apparently I did not understand the breaks, and thought it was a natural E car. Then you can remove weight and go up to E, or add to go down to G-think I get it now!! Thanks again!

01-06-2008, 05:03 PM	#4
Johnny U Junior Member Join Date: Jul 2006 Location: Oakville Ontario Canada Posts: 55 Likes: 0 Liked 0 Times in 0 Posts	Re: pls help with classification math Stage1scott to further clarify the classification, to run the Buick in g/sa the min. weight with driver would be 3800lbs. Multiply 11 (G factor) by 330 (rated HP) and add 170 for driver. I have a 71 GS that I ran in G/SA and I had to add weight to achieve 3800. When I ran it in F/SA a few years back I could just barely get it to mimimun weight and that was when the HP rating was at 335(I think it came down in 2002). This past year I ran SS/LA with the stocker motor and my min weight was 3875 and I had about 240 lbs of extra weight added to make the min weight. Hope this helps some.

01-06-2008, 05:58 PM	#5
stage1scott Member Join Date: Dec 2003 Location: Cornville Posts: 406 Likes: 1,870 Liked 108 Times in 44 Posts	Re: pls help with classification math hey Johnny, thanks that helps even further. and makes me see the reason for a weight box. My low 13 second street car (72, a/c,cruise, drag radials) weighed 4138 with me in it (190 lbs) and a half tank at fontana in november, so I could see 3400 lbs in an "empty" race car, although it would take some weight loss concentration to get to D wieght in a 70, I guess. what rear ratio does it take to move these things competitively? at these weights? and also, since my interest is now all over the place, what cyl heads are you allowed in SS? still the cast iron heads, with small valves for the non-stage 1 engine?? but any camshaft/rockers?? thanks for the info in advance, I am always stunned at how fast legal NHRA stock and super stockers are these days, and a being a Buick owner/enthusiast, am interested in how these cars are running in the curent rules structure. Someone over on V8 Buick.com told me Jason line's old car is in the pacific northwest, D/SA, has run some 10.40s!!! that is just amazing to me! Last edited by stage1scott; 01-06-2008 at 09:48 PM.

01-06-2008, 09:47 PM	#6
Johnny U Junior Member Join Date: Jul 2006 Location: Oakville Ontario Canada Posts: 55 Likes: 0 Liked 0 Times in 0 Posts	Re: pls help with classification math I use a 4.30 gear in my stocker/ss car. Also a 2.75 low gear in the trans helps immensely to get the car off the line but with the 4.30 rear it keeps the trap rpm around 6000 to 6200 rpm. I believe that Jasons old car is now owned by Alf Wiebe and I heard that that thing has been in the low 10.30s if im not mistaken. In SS you have to use the cast iron heads for the year that you claim, small valve if you use the 330 hp motor or you can use the stage one size valves but the HP rating is higher and it will put you up 2 classes at approx. the same weight. Talk to you later.