'70-1/2 GT-37 WT-code 400 horsepower rating
 

Guys,

I am aware that 345 hp is the accepted rating for the WT-coded 400 in the '70-1/2 GT-37 as opposed to 350 hp in the GTO, but I'm trying to find that stated in a Pontiac-printed source. Has anyone seen one?

Thanks!

Rocky, I've only seen the 330 hp 400 4-bbl listed for both auto and manual in the Pontiac Dealer/sales letters that are on GT-37.org. I've only seen the 345 hp number in discussions and always wondered where that came from too.

Sorry I couldn't shed official light on this for you, but maybe BVZ, OPH, or Ransom may know something.

Dennis

I would be interested in knowing which brochures ect have different ratings;
I had always assumed that the 350hp rating was used on the GP & A-bodies;
I thought the 330hp rating was only for the Firebird...

But, I just looked, and found THIS and THIS and THIS (there's also more in that prestige brochure) and low, and behold, there we have a 330hp rating on the Tempest/Lemans!

Thanks, Dennis. I have the bulletin that denote when the 400 is equipped with a 3-speed or 4-speed manual transmission, the GT-37 drive line mirrors the GTO's. Why it would be rated lesser doesn't make sense to me. I'm really hoping to find something concrete.

The ‘70 Powertrain Chart also shows 330hp.

http://www.gt-37.org/gallery/index.p...5&mobile=false

Here is the AMA doc.

Rocky, I think the 330 (345) hp rating was to keep the non-GTO power above the weight ratio to 10 lbs/hp max for insurance and NHRA class advantages. The 70 GTO was never lighter than 3700 lbs stripped, so even with the RAIV's 370 hp, it was no less than the 10 lbs/hp PMD seemed to ascribe to in those days. A stripper Tempest 2-dr post coupe could weigh almost 300 lbs less than the GTO, so 345 became the WT hp number based on the 10 lb rule.

Dennis

Can you verify where they find 300lbs to remove from these cars? I think it was brought up before that this figure was based on the AMA specifications, however, which listed T37 weight the with 6 cylinder. I am just not seeing 300lbs in sound deadener and bucket seats vs bench.

68bird400HO,

Here is from my Tempest thread in this section...

"The previous owner weighed the Tempest the one time he had it at the track and it weighed 3650 lbs with him in it and a half tank of gas....he weighs at least 225 lbs, and I'm at 150 lbs, so 3575 lbs with behind the wheel. I plan on swapping it to manual steering which will shed another 30 lbs, so it'll be 3600 lbs with me and a full tank of fuel. That is almost 500 lbs lighter than my '70 Judge (4080 lbs with me)! I wish they put RAIV's in stripper Tempests in '69 and '70...they would have been game changers!"

The two cars are comparably equipped with V8's (400's), power steering, automatics (TH400's), radios, weighed on NHRA certified scales, with drivers. The Tempest was weighed without the spare & jack assembly (60 lbs.) and a half tank of gas (61 lbs.). If you add that to the Tempest's weight (with factory sound deadener, etc.) then minus the driver difference of 75 lbs. (3650 + 60 +61 -75 = 3696 lbs. with me (150 lbs.), or 3546 lbs. curb weight. The AMA curb weight of a '70 GTO is 3781 lbs. + 31 lbs.(PS) + 29 lbs.(TH400) + 8 lbs(radio) = 3849 lbs. curb weight. So that is a 400 lb. difference...sorry not 300 lb. My Judge weighs 4080 lbs. with me, or 3930 lbs. curb weight (exactly what my title lists) with the spare and full tank of gas, right on the AMA spec weights. The '70 Tempest is much lighter for some reason and weighs they same as my brothers '71 455HO T-37 (+/- a few lbs.).

The AMA weight for the '70 Tempest is 3336 lbs. + 245 lbs. (400 4-bbl.) + 29 lbs. (TH400) + 31 lbs. (PS) + 8 lbs. (radio) = 3649 lbs. curb weight vs. 3546 lbs. actual. AMA GTO weight of 3930 lbs. minus AMA Tempest weight 3649 lbs. = 281 lbs., so close to 300 lbs. by AMA standards.

Both cars are factory stock with all their born-with stuff...no weight removal in either.

Dennis

Thanks, Dennis. And I should have clarified, I'm not contesting the 330 hp rating, just wondering if/where the 345 hp rating is published in a Pontiac-printed source.

as far as weight differences, 40 years ago john sawruck and I were talking about my 70.5 GT37 400 3 speed manual car and how much lighter it was than a comparable gto. we started making a list of stuff we could come up with. example, gto front bumper heavier than the gt, rubber mat lighter than carpet, really cheapo door panels, seats etc compared to the gto. he also sent me copies of paperwork from Pontiac that showed performance tests on all their 70 year models. and the fastest 1/4 mile time was a GT-37 400 4 speed (WT with 12 heads) and a 3:90 posi. yes it was faster than a ra4 gto and firebird.

Wow!!

Original documentation on the development of the GT-37 states the 330 hp rating should be used to adhere to the insurance companies premium penalty for when a vehicle's rating was over 10.5 lbs/hp. The proposal for the Tempest GT (later called GT-37) was 10.62 lbs/hp, and if the 27 series was offered, it would be 10.55 lbs/hp. Back in October 1969, Tom Goad special ordered a 3327 1970 Tempest with D98 stripes, 3.90 gears, 4-speed, etc. which would lead to the GT-37 model. Goad's car was the Cardinal Red one that was used in photo shoots. Goad kept pushing this proposal on Pontiac and showed the car to Zone Managers in December 1969, but it wasn't until March 1970 when he finally received the green light from James McDonald for production. As a side note, Goad states the car's performance is "close to that of a RAIV GTO", but not faster.

Knafel Pontiac offered the "Magnum 400" based off Goad's 1970 Tempest 3327 that was shown at the Zone Managers meeting. The other dealer that was interested in offering a car like this was Blue Ribbon Pontiac. Ben Harrison wrote up the Engineering Request for cost analysis based on the "Marketing Schemers" proposal on March 20th, 1970.

I've only seen the 330 hp rating.

Mike

I wish I had that paperwork easy to post, but one of the many pics, literature that was boxed away when I moved 20 years ago and I haven't came across yet. like I said john sawruck gave it to me and it was a list of all the 70 model vehicles and showed their different specs. I cant say for certain, but it seems like the GT-37 was a tenth or two faster than the ra4. (if I remember correctly the ra4 was using a 3:90 gear also.)

From what I understand, 100 lbs of weight loss translates into about 0.1 second ET drop. So the 300 lb savings on the GT would make it about 0.3 faster than a standard gto 400 with 3.90 rear. That means that the anecdotal information being stated here suggests that the RAIV motor is only worth a tenth or two over the standard 400. Doesn't seem quite right.

Gary,

Interesting as I had a very similar conversation with John Sawruk at the Pure Stock Drags back 15 years, or more, ago and he was describing a Silver with black guts Tempest post coupe a fellow engineer at the proving grounds (Black Lake in Milford?) ordered with the WT 400, I believe the std. M-13 3-speed trans, 3.55 Saf-t-track, and G-70 blackwall tires on black steel wheels & dog dishes, and maybe, PS & PDB's. He wrote the options on a piece of paper I had in my car and I still have it in my files. I'll have to scan it and post it in a few days. John said he swapped in an M-20 4-speed trans and that it was hard to beat in the quarter mile.

Dennis

Mike,

Thanks for the clarifications with actual facts. I was going off memory and the 10.5 lbs/hp is definitely right. It appears there were a few Tempests with the WT 400 4-bbl's running around ordered by PMD engineers.

Dennis

dennis, im sure you knew john a lot better than I did, but I never knew him to say stuff that wasn't factual and like I said he had the paper he gave me showing that showed various things like top speed, quarter mile times, braking distances, mpg etc... but I do remember that when comparing the 400 , ram air 3 and ram air 4 A bodies and F bodies there was very little difference in the quarter mile times.

Here is the hand written note from John Sawruk from the time when he and I were discussing the Tempest 400 cars and the elusive 4-speed WT code 400 cars that he said very few were ordered, but were out there. The PMD employee (engineering foreman) was a Paul Kolowitz (Kolomitz?) that ordered Engr. Co. Car #0021. You can see in the picture of John's note how he recalls it was ordered...no PS/PDB and the 3-spd was swapped for a 4-speed tranny and Rally II's were added as well. John remembered the car well but didn't know what happened to it like so many other neat engineering cars they tested.

My dream is to find a '70 Tempest post coupe WT 400/4-speed like this one.

Dennis

For what it's worth, Sawruk also claimed the Tempest's 400 was the equivalent to the RAIII without the induction plumbing. We now know that not to be true.