Regarding the under hood AC stuff, IIRC, only the inner suitcase is from a GP. The rest is original.

Also, in the past I have opined that this car did not have the nipple for the hood tach. Looking carefully at one of the first pictures I ever took of the car I can CONFIRM that a nipple was present on the old suitcase.

Cool picture Mike! Please post more! Yep, you sure can see the nipple and I have an original one for the new A-body suit case I got for the GT.

Dennis

Looks like the hood tach heater/AC box nipple mounting instructions weren't closely adhered to at the factory. Compare the pic of the GT-37's original nipple location to a restored original '71 GTO at MCACN a couple years ago. I'll be using Mike's picture as a guide on the new AC suitcase.

Dennis

Here you go Dennis. This is on my HO convert.

Jeff, Thanks for posting the nipple from your convert. Interesting that it is in the identical position as on Dan McGuire's '71 GTO. What plant was your LeMans assembled? The GT-37 is a Fremont, CA car.

I wonder if it was a plant-thing as it looks like the GT's nipple is further to the passenger side of the case. I'm also curious to see what the assembly manual shows for the measured location.

Dennis

On the original inner AC boxes for '71 & '72 GM A-bodies, there is a small divet; a small impression where you drill the hole for the hood tach drain fitting to go into the box. Years ago I compared the location on the inner box of the T-37 Coupe (factory hoodtach car) to that of several AC boxes I'd pulled out of '71 & 72 LeMans & Cutlass parts cars. The small impression divet was on all of those '71-72 inner AC box covers. Earlier this year I sent tjs1972 on this board, an inner cover off the low mile 01C Pontiac built '72 LLM. Even in mid '72 production, with no factory hood tach avail, the small divet was still part of the molding of the inner box. That particular inner cover, inside there was the part number & Revision 7.

Years ago on v8Buick.com there was a very good discussion as to the factory use of the Gray tinted AC boxes & transition to the more Brown tinted ones. Having pulled & cleaned up a BUNCH of unfaded original '71 & 72 A-body AC boxes, they all def were of the "brown tinted" variety. Its been over a decade since I posted on v8Buick.com, that particular thread may have disappeared after the site was hacked, crashed, & a new format was rolled out. I'd bet Duane or George N. contributed on that thread. Dennis, if youre a member over there, might be worth doing a search, my memory is foggy but I believe the consensus was the brown tinted style showed up sometime during 70 production. A-body wise I've had a TON more '71's & 72 parts cars than '70's, just something i keep an eye out for.

Jeff, on your drain hose routing, the two snap style clips, side by side, that doesn't look right to me.... can't remember seeing factory routing that way before. Conversely, that have been an example of the Asm line worker, "had these AC wiring harness routing clips handy, & just zipped them in place".

Thanks Roger, I'll take a look at my new AC suitcase for the dimples.

Dennis

Hi Roger. You are correct. The previous owner installed the clips and ran the vacuum line that way. He knew that it was not correct but wanted to clean it up a bit. I just left them in place. Also, The A/C suitcase in my 71 does have the grayish color and I believe it to be the original.
I have also included a few photos of a 71 Judge with NO A/C and a hood tach which is probably closer to how the factory ran the vacuum line to the tach from the nipple.

Roger, You can also see 2 divots in my believed to be original A/C suticase and neither one of those are used for the nipple hole.

It's time to get this bad boy back on track after yet another diversion (a '70 RAIII Formula 400 Firebird). I'll be working on getting the newer dash assembled and getting the drivetrain wrapped up. I might even consider dynoing the 455 motor to see how the 197 HO heads (8.6 SCR) & RA manifolds stack up against the #15 small valve hi compression heads & std. manifolds (10.0 STR that made 390 hp and 512 tq).

Dennis

Started working on swapping all the hardware from the original dash to the replacement this weekend. It looks like I'll be ordering repop gauges the replace the original gauges since it would be double to triple the costs to have the originals rebuild/restored.

Anyone ever notice the difference fonts on the wiper switch? The dirty one on the right is the original one from the GT-37. The left one is from a '72 (?) from what I've been told.

Dennis

455HO Going to the Dyno
 

This Friday we are going to dyno the 455HO motor that we pieced together with the .040 over 455 that was formally in the '70 Lemans that was rebuilt with forged rods and pistons about 6 years and 1200 miles ago...its almost broken in. The #15 small valve 455 heads (10 to 1 SCR) were removed and fresh HO 191 heads are now in their place along with vintage factory round port HO exhaust manifolds. The GT-37's original aluminum intake and crossover are in their rightful place and we'll be using a 7041267 Qjet. The cam is the Summit 2802 that was installed back in 2014 along with the 951 lifters that show no unusual wear. The heads measured at 108 cc's and the pistons are .015" in the hole, so .027" Cometic head gaskets keep the quench at .042" and the SCR at 8.61. We are hoping to match the power the short block made with the #15 small valve 455 heads and log exhaust manifolds of 390 hp @ 4600 rpm/512 lbft @ 3400 rpm. We are hoping that the better flowing HO heads and RA exhaust manifolds will offset the 1.4 pt. compression deficit. Keeping our fingers crossed!

Dennis

Dennis , you ever dyno test RA manifolds versus headers ?

Mike - Believe or not, we don't own any headers since we are so entrenched in the Pure Stock Race world...only do logs and RA manifolds, lol. We are installing the HO RA manifolds today or tomorrow (B131 casting dates).

Dennis

Good Dyno Session for 455HO
 

We were able to make 10 pulls starting at 10 am and finished by 11:30 am. The 1st pull to establish a baseline was 410 hp @ 4800 rpm/515 lbft @ 3600 rpm...20 hp and 3 lbft torque better than with the small valve high compression #15 heads with log manifolds. We started with 38 degrees total advance and BU (0.0547 short tip) secondary rods in the 7041263 Q-jet. The factory HO exhaust manifolds (with the puny 2.1" outlets) with Pypes 2.5" mandrel downpipes tied into 10' of straight 2.5" pipe, so 14'-15' of exhaust pipe.

We richened the secondary's twice ending up with CC's (0.0300" medium tip) and improved to 420 hp @ 5000 rpm/32 lbft @ 3600 rpm. We them bumped the timing to 41 degrees, replaced the small long pipes with the dyno room 8" dumps for the downpipes to flow into, and added the air cleaner base and got the best hp & tq for the session at 431 hp @ 5000 rpm/539 lbft @ 3600 rpm.

We are certain if we had used RARE 2.5" outlet repro manifolds we could have added 3-5 to the hp/tq numbers across the pull range (3000 - 5500 rpm). HP peaked at 5000 rpm typically and held on to 5400. Overall, we were very satisfied with the 2802 Summit cam and it worked very well with our 8.6 static compression ratio. The weather conditions put the DA at over 2000 feet (69 degrees/29.00 barometric pressure/71% relative humidity).

Dennis & Dan

Very nice for such low compression

Great results Dennis . That's why I asked about the factory HO manifolds I thought they were a little smaller . I have the 2.5 RA d port manifolds on the T37 , should be in the high 11s this year . I have a set of hooker super comp headers on the shelf but don't want to use them .

Mike - Thanks! The HO made 400 hp (+) from 4000 rpm to over 5500 rpm where we ended the pulls. It made 500 lbft torque from 2900 rpm to 4400 rpm. The hp was dropping (slowly) after 5000 rpm. We are hoping that with a tight rear suspension for 2.0 60' times to be able to run hi-12's at 108 mph with the 3.31 gears out back. It will have a wide ratio BW-ST10 (2.66 1st gear) to help with a decent launch on bias plys.

Dan dyno'd a RAIII 400 many years back and compared logs (2" outlets), to factory RA A-body (2.12" outlets), and to factory long branch manifolds (2.35" outlets) and they power increases went in that order. The long branches made 3-5 hp/tq over the entire pull over the A-body RA manifolds and, though, we haven't compared the factory HO manifolds to the 2.5" RARE manifolds, we surmise the results would be similar with the outlet's .35" diameter increase. We were shocked at how well the D-port logs did on the 068 cam'd 400 with 10.5:1 compression (365 hp/440 lbft). The choke-off point happened at a lower rpm compared to the RA manifolds, while the long branches carried the power further into the higher rpm range...no surprises there.

Your T-37 is running great! I hope you break into the 11's this year...pulling for you!

Dennis

I don't know if it's legal for your racing but do you know of anybody that used manifolds that have been prepared using extrune hone ? Probably not worth much with lower rpm but I thought I read somewhere that it was being used in factory type racing classes . I don't know how you guys do it on those little bias tires . Really cool

Extrude honed