Wheelbase/HP Relationship??

RJ Sledge · 10-05-2008, 10:24 PM

Is this something that every combo has, or is it just certain ones? The reason I ask is that there are several engine combo's that are identical and depending on the wheelbase of the vehicle they have different HP ratings?

Whats up with that? For instant, Mopar 383/330 is rated at 280 in a big car and 287 in a small car(soon to be 294). Same motor, just different HP ratings. The only difference is the wheelbase 116/108.

The motors are identical.

This does not seem right. If it is right how come this is not done with the Fords and Chevrolets?

Later RJ

Jeff Lee · 10-05-2008, 10:35 PM

The 383 / 280 engine is the non-magnum engine; smaller cam than the 383 Magnum engine. Might even be a slight decrease in compression, check the specs. As used in the '67 A-Body cars, it also suffered from a very restrictive cast iron exhaust manifold.
The WB has nothing to do with anything. But sometimes it is a reflection on what is being run in competition and subsequently it may be hit by the AHFS.

RJ Sledge · 10-05-2008, 10:50 PM

Jeff

We are not talking about Pure Stock with factory exhaust manifolds here, we are talking about identical engine specs for these motors, regardless of what the Factory Rating was. We have the same motor being factored by Wheelbase and nothing else. Do you think that this is right?

R J

SSDiv6 · 10-05-2008, 11:03 PM

R J, could you be more specific in the particular car bodies?
Are we talking about A-Body vs. B-Body or A-Body vs. E-Body?

RJ Sledge · 10-06-2008, 09:33 AM

From what I read on the Classification and Blue Print Specs is that the 280 hp motor and the 325/330 HP motors are all identical as far as carb, cam, intake, rocker ratio, cam lift, deck, gasket, etc., etc.. So why are they separating the HP ratings on these motors according to "A" Body, "E" body, "B" Body "D" Body or Any Body and No Body???? I realize that the transmission does make a difference in the AHFS and it should be that way. What I am confused about is why the difference in the Wheelbases and "Body" differences?

I am really confused here and would appreciate it if somebody could explain why a Wheelbase is even considered a reason for different HP Rating.

Thanks RJ

SSDiv6 · 10-06-2008, 11:49 AM

Quote:

Originally Posted by r sledge

From what I read on the Classification and Blue Print Specs is that the 280 hp motor and the 325/330 HP motors are all identical as far as carb, cam, intake, rocker ratio, cam lift, deck, gasket, etc., etc.. So why are they separating the HP ratings on these motors according to "A" Body, "E" body, "B" Body "D" Body or Any Body and No Body???? I realize that the transmission does make a difference in the AHFS and it should be that way. What I am confused about is why the difference in the Wheelbases and "Body" differences?

I am really confused here and would appreciate it if somebody could explain why a Wheelbase is even considered a reason for different HP Rating.

Thanks RJ

R J, there is an actual difference in performance when the same engine is used in the various body styles. The combination will perform differently when put in an E-Body to a B-Body and from a A-Body to an E-Body. Ask Larry Hill how his engine combo would perform from a B-Body (Charger) to an E-Body (Cuda).

RJ Sledge · 10-06-2008, 12:08 PM

You know, now that I heard somebody explain it that way it makes a lot of sense.....

I have one question for anybody who would like to explain to me......is how come all the makes of cars are not adjusted this way?

I would like to see all Stock and SuperStock combo's done this way, anybody else feel that way? If it is good for the Mopars why not everybody else, or is there a hidden agenda in the NHRA Classification Guide group???

Maybe Travis could add something to this?

This does not seem right to me and should be an easy fix without a lot of hassle.

R J

Stewart Way · 10-06-2008, 01:41 PM

It does happen in other makes. Check the 1969 Chevy 350/300. In the big car and the Vette its 290 in S and 310 in SS regardless of transmission type. But in the Chevy II and Camaro its 290 in S and 310 in SS stick but 318 in SS auto yet the big cars and the vette are at 310 for the SS auto. Think it has to do with how the AHFS hits a combo with regard to family. I would guess if we looked at enough Ford we could come up with the same thing.
As usual i could be wrong

John Lang · 10-06-2008, 03:31 PM

If you check the years of the 383's as in 67 and 68's the exhaust valve changed from a 1.60 to a 1.74 , with a change in the cyl head # from a 916 to , i forgot the # for 68 - 70 head. I guess that is whats known as a senior moment!.....John............. It's back, it;s a 906 Head

RJ Sledge · 10-06-2008, 05:55 PM

John.....You are probably right about the difference between the 67 and 68 383's, what I was referring to was the difference in HP rating based solely on wheelbase in the 65-67 years for the 383 motors (280 HP has the same specs as the 325/330 HP). The big cars were rated at 280 and the smaller cars were 287.

I don't see a problem here with doing just that, as long as everyone is on the same LEVEL Playing Field. From what I have seen on the Classification Guide and the Blue Print Guide that is not the case for some engine combo's.

Looks like NHRA has already set a precedent with the Mopar ratings, why shouldn't every body have the same thing?

Do you think it should be??

Stewart....

I feel that the situation with the Chev combo you mention is that it has been run for so long and been changed up and down that it would be very hard to figure that particular combo out, one would have to go back a long way to see where it started off and follow the changes, and that would be very difficult. With the Mopar and other odd ball combo that were not as common or as good a combo as the 350 Chevrolets it is much easier to check. I don't remember many cars with the 383 combo running before a few years ago (2000?).

It should be the same for all makes with the same engine, not just for one brand

RJ

10-05-2008, 10:24 PM	#1
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Wheelbase/HP Relationship?? Is this something that every combo has, or is it just certain ones? The reason I ask is that there are several engine combo's that are identical and depending on the wheelbase of the vehicle they have different HP ratings? Whats up with that? For instant, Mopar 383/330 is rated at 280 in a big car and 287 in a small car(soon to be 294). Same motor, just different HP ratings. The only difference is the wheelbase 116/108. The motors are identical. This does not seem right. If it is right how come this is not done with the Fords and Chevrolets? Later RJ

10-05-2008, 10:35 PM	#2
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Wheelbase/HP Relationship?? The 383 / 280 engine is the non-magnum engine; smaller cam than the 383 Magnum engine. Might even be a slight decrease in compression, check the specs. As used in the '67 A-Body cars, it also suffered from a very restrictive cast iron exhaust manifold. The WB has nothing to do with anything. But sometimes it is a reflection on what is being run in competition and subsequently it may be hit by the AHFS. __________________ Jeff Lee 7494 D/S '70 AMX

10-05-2008, 10:50 PM	#3
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Re: Wheelbase/HP Relationship?? Jeff We are not talking about Pure Stock with factory exhaust manifolds here, we are talking about identical engine specs for these motors, regardless of what the Factory Rating was. We have the same motor being factored by Wheelbase and nothing else. Do you think that this is right? R J

10-05-2008, 11:03 PM	#4
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 3,036 Likes: 710 Liked 1,538 Times in 575 Posts	Re: Wheelbase/HP Relationship?? R J, could you be more specific in the particular car bodies? Are we talking about A-Body vs. B-Body or A-Body vs. E-Body?

10-06-2008, 09:33 AM	#5
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Re: Wheelbase/HP Relationship?? From what I read on the Classification and Blue Print Specs is that the 280 hp motor and the 325/330 HP motors are all identical as far as carb, cam, intake, rocker ratio, cam lift, deck, gasket, etc., etc.. So why are they separating the HP ratings on these motors according to "A" Body, "E" body, "B" Body "D" Body or Any Body and No Body???? I realize that the transmission does make a difference in the AHFS and it should be that way. What I am confused about is why the difference in the Wheelbases and "Body" differences? I am really confused here and would appreciate it if somebody could explain why a Wheelbase is even considered a reason for different HP Rating. Thanks RJ

10-06-2008, 12:08 PM	#7
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Re: Wheelbase/HP Relationship?? You know, now that I heard somebody explain it that way it makes a lot of sense..... I have one question for anybody who would like to explain to me......is how come all the makes of cars are not adjusted this way? I would like to see all Stock and SuperStock combo's done this way, anybody else feel that way? If it is good for the Mopars why not everybody else, or is there a hidden agenda in the NHRA Classification Guide group??? Maybe Travis could add something to this? This does not seem right to me and should be an easy fix without a lot of hassle. R J

10-06-2008, 01:41 PM	#8
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	Re: Wheelbase/HP Relationship?? It does happen in other makes. Check the 1969 Chevy 350/300. In the big car and the Vette its 290 in S and 310 in SS regardless of transmission type. But in the Chevy II and Camaro its 290 in S and 310 in SS stick but 318 in SS auto yet the big cars and the vette are at 310 for the SS auto. Think it has to do with how the AHFS hits a combo with regard to family. I would guess if we looked at enough Ford we could come up with the same thing. As usual i could be wrong Last edited by Stewart Way; 10-06-2008 at 01:50 PM. Reason: mistake

10-06-2008, 03:31 PM	#9
John Lang Member Join Date: Oct 2003 Location: Sheboygan Wi Posts: 391 Likes: 0 Liked 6 Times in 2 Posts	Re: Wheelbase/HP Relationship?? If you check the years of the 383's as in 67 and 68's the exhaust valve changed from a 1.60 to a 1.74 , with a change in the cyl head # from a 916 to , i forgot the # for 68 - 70 head. I guess that is whats known as a senior moment!.....John............. It's back, it;s a 906 Head __________________ John Lang 365 STK, SS

10-06-2008, 05:55 PM	#10
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 496 Liked 288 Times in 90 Posts	Re: Wheelbase/HP Relationship?? John.....You are probably right about the difference between the 67 and 68 383's, what I was referring to was the difference in HP rating based solely on wheelbase in the 65-67 years for the 383 motors (280 HP has the same specs as the 325/330 HP). The big cars were rated at 280 and the smaller cars were 287. I don't see a problem here with doing just that, as long as everyone is on the same LEVEL Playing Field. From what I have seen on the Classification Guide and the Blue Print Guide that is not the case for some engine combo's. Looks like NHRA has already set a precedent with the Mopar ratings, why shouldn't every body have the same thing? Do you think it should be?? Stewart.... I feel that the situation with the Chev combo you mention is that it has been run for so long and been changed up and down that it would be very hard to figure that particular combo out, one would have to go back a long way to see where it started off and follow the changes, and that would be very difficult. With the Mopar and other odd ball combo that were not as common or as good a combo as the 350 Chevrolets it is much easier to check. I don't remember many cars with the 383 combo running before a few years ago (2000?). It should be the same for all makes with the same engine, not just for one brand RJ