AS PROMISED REPORT

[wildfelr]

RQB3263/81/305  THE DISC BRAKE CONVERSION DID NOT HAPPEN .... VENDOR COULD NOT SUPPLY KIT IN TIMELY FASHION .... ORDER CANCELED W/ SUMMIT AND REFUND  $ 850 RECEIVED+++DRUM BRAKES WORK JUST FINE... MIKE MYER INSTALLED AN EDELBROCK  INTAKE AND HOLLY 500CFM ....OH WOW ... WHAT AN UNBELIEVABLE DIFFERENCE IN PROFORMANCE AND NOW  19.5 MPG..... CAUTION... HOOD CLEARANCE IS AN ISSUE WITH THE TALLER MANIFOLD.....  WILL BE INSTALLING NEW SPOILER AFTER DAMAGE  BUT THAT IS ANOTHER STORY BETTER LEFT UNTOLD.....  BILL

[Stacey]

What motor is in your car? I have a 305 in my 1991 and am in the middle of switching rear axle gears for a bit more performance. Next step is motor work or motor replacement.

[wildfelr]

RQB3263/81/305   I HAVE THE ORIGINAL 305,  WITH A  CRANE TORQUE CAM (RV) ,...EDELBROCK 2701 MANIFOLD, HOLLEY STREET FIGHTER  4BBL, TRUE ALL S/S DUAL EXHAUST,  HIGH TORQUE STARTER,  HEI. IGN......133,000 ORIG  MILES ON BOTTOM END...NO OIL CONSUMPT...19.5 MPG ... 700R4 OD TRANS  CRUISES 70 @ 1800 ....WITH 2.72 REAR GEAR......PERFECT  SET UP...IT WILL NEVER BE ANYMORE THAN A COOL SOUNDING CRUISER/ATTENSION GITTER ....BILL

[John D]

duplicate...

Edited May 15, 2023 by John D

[John D]

Just installed a Edelbrock Performer 2701 on my 79 as it had a TM-1 ("Torker") single plane with a AFB when I bought it. Still finishing it up. The Torker is really made for 3000 rpm on up whereas the Performer EPS dual plane is designed for driveability from idle on up. 

The 2701 is 0.3" taller than the TM-1. I appear to have lots of room. I suspect it is due to the C4 Corvette front frame and suspension that the 350 is mounted on. I'm also removing the steel Stude style surge tank that was installed. It does appear to be too close to hood, as the hood paint is blistered where that tank is closest to it. 

Looking forward to see if drivability is improved. I've been blaming the 9625 AFB a bit. I was thinking about trying a Holley but 500 cfm seems small for a 350. We'll see in the next day or so, but this is a great data point. Do you have a model # for the Holley? I don't see a "street fighter" on their site nor do I see a 500 cfm 4 barrel.

[Steve-Avanti]

9 hours ago, Stacey said:

What motor is in your car? I have a 305 in my 1991 and am in the middle of switching rear axle gears for a bit more performance. Next step is motor work or motor replacement.

Do you have the 200r4 trans.?  What gear ratio are you considering? Those that I've spoken with recommend 3.55 or 3.73 for a noticeable improvement in acceleration.

[wildfelr]

RQB3263/81/305 ... THE RV CAM I INSTALLED OPERATES  IDLE TO 2500 RPM AND THATS EXACTLY WHERE I DRIVE

THE HOLLEY  # 0-80457S 

A 305 WILL NEVER BE A PROFORMANCE  PACKAGE BUT WILL BE  AN AWSOME CRUISER

MORE CUBES AND MORE RPM MEANS MORE FUEL CONSUMPTION

I THINK YOU WILL BE UNHAPPY WITH A REAR GEAR CHAANGE BUT THEN IM PUSHING 80 AND DRIVE LIKE IT

ROLL ON....BEST WISHES .... BILL IN FLORIDA

[Gunslinger]

More power also means more heat...something an Avanti already has issues with.  

[wildfelr]

RQB3263/81/305   ,ELCORRECTO..... I HAVE THE ORIGIAL RADIATOR WITH DUAL 12" ELECTRIC FANS FROM DUREAL....EITHER FAN  WILL DO THE JOB JUST FINE BY ITS SELF.....REDUDUNCY  WILL BRING YOU HOME IN A PINCH....ALSO I HAVE A 16" PUSHER FAN IN FRONT ON THE    AC CONDENSER  WIRED THRU A RELAY (ALL FANS ARE ON RELAYS AND I  CARRY SPARES) TO THE A6  COMPRESSOR CLUTCH AVAILABLE IN A PINCH BUT IVE NEVER USED IT....... ALSO FROM MAY TO NOVEMBER ...I USE 3/4" SPACERS (4) UNDER THE HOOD LATCHES GIVING HOT AIR ANOTHER ROUTE OUT (REQ LONGER BOLTS)... ALL WITH 180 DEGREE THERMOSTAT AND AN ALL CAST IRON ENGINE NEVER HAD  EVEN THE SLIGHTEST PROBLEM.... RIDE ON .....BILL

[wildfelr]

RQB3263/81/305    OK I ALMOST FORGOT .... HIGH FLOW WATER PUMP AND AUX TUBULAR ALUM DOUBLE PASS  TRANS COOLER (NO TRANS HEAT INTO RADIATOR ....THAT  NEVER MADE SENSE ANY WAY) .... BILL IN FLORIDA

[Stacey]

16 hours ago, Steve-Avanti said:

Do you have the 200r4 trans.?  What gear ratio are you considering? Those that I've spoken with recommend 3.55 or 3.73 for a noticeable improvement in acceleration.

I think? it is the 700R4, but might be the 200R4, not sure, other than it is 4 speed auto. Seems I have a 2:28 rear open gear now, as we speak going with a 3:73 posi unit. I figured at first i was going to just replace the 305 and go with a 350, but got talked to do it in steps. Gear first and see how I like it and if need be, then new motor. Where we live the car is never run at high speeds, maybe 60ish is as fast as we run. Normally all town cruising. Do not care what amount of fuel it uses, fill it up when it gets low, almost never has the top up, so it is a fun convertible to beebop around town.

[Gunslinger]

For the average Avanti a 200R4 is a better choice for an automatic than a 700R4.  It has a better spread of gears and can be built to be stronger than necessary for the application.  The 700R4 was designed for larger heavier vehicles and performance applications.  My ‘70 had a 700R4 and the 1-2 shift was nearly immediate and very abrupt.  It was far too easy to spin the tires in any gear.

Another potential issue with the 700R4 is due to its bigger case…it often requires new neutral safety switch and backup light switch arrangement to be fabricated.  There are differences in Avanti body dimensions so that need is not universal.  

A good transmission builder can take into account the engine size, horsepower and torque, cam specs, rear axle ratio, weight of the vehicle and build a transmission to make for a great driving Avanti.
 

 

[John D]

On 5/15/2023 at 6:59 AM, wildfelr said:

RQB3263/81/305 ... THE RV CAM I INSTALLED OPERATES  IDLE TO 2500 RPM AND THATS EXACTLY WHERE I DRIVE

THE HOLLEY  # 0-80457S 

A 305 WILL NEVER BE A PROFORMANCE  PACKAGE BUT WILL BE  AN AWSOME CRUISER

MORE CUBES AND MORE RPM MEANS MORE FUEL CONSUMPTION

I THINK YOU WILL BE UNHAPPY WITH A REAR GEAR CHAANGE BUT THEN IM PUSHING 80 AND DRIVE LIKE IT

ROLL ON....BEST WISHES .... BILL IN FLORIDA

thanks, that's a 600 cfm carb. I suspect he did some tuning...

[John D]

Just test drove the Performer EPS 2701 manifold with the same Carter 9625 carb (was a TM-1 Torker manifold), WHAT A DIFFERENCE! Yes it's notably taller. So much more drivable below 2500 rpm. The mixture screws are a half turn in vs before so I'm going to play with the metering rods a bit too. Well worth the 200 bucks and shop time! 

[Steve-Avanti]

On 5/15/2023 at 2:44 PM, Stacey said:

I think? it is the 700R4, but might be the 200R4, not sure, other than it is 4 speed auto. Seems I have a 2:28 rear open gear now, as we speak going with a 3:73 posi unit. I figured at first i was going to just replace the 305 and go with a 350, but got talked to do it in steps. Gear first and see how I like it and if need be, then new motor. Where we live the car is never run at high speeds, maybe 60ish is as fast as we run. Normally all town cruising. Do not care what amount of fuel it uses, fill it up when it gets low, almost never has the top up, so it is a fun convertible to beebop around town.

Very interested in your impressions when the 3:73 is in & you've driven it.  I have an 87 w/the 305 & very mild gear (good mph but uninspiring acceleration).  Seriously considering 3:55 & 3:73. Thx!

[Stacey]

I am currently driving back to home in Az from Alabama in the motorhome. Should be back there I think Sunday and will see if the car is done so i can pick it up Monday. Will let you know the seat of the pants impression as to if it was a worth while investment. I have high hopes to see/feel the thrill of drivng it in a more spirtited fashion. It was/is a nice car, just a dog.

[Steve-Avanti]

Cool👍👍

[plwindish]

A few thoughts about the above topic:

1.  Rear Disc brakes - I'd love them for my '76, but rebuilt the drums after the Turner rear kit did not fit (in 2011). The Turner's upfront are fine.

2. 200R4 trans was installed in my '76 after the 400 SBC was overhauled and updated in '11. I've been very happy with it and put over 50,000 miles on it since installed, rebuilt last year.

3. Even after overhaul, headwork, 400 still would overheat if in hot weather and stuck in traffic. Went to switch to EFI in '17 and found a cracked head with some cylinder damage necessitating another rebuild, this time with aluminum heads and re-cored radiator seems to have eliminated the problem. Car runs great now.  20-20 hindsight in effect, I might have gone with a 383 crate motor or LS when I got the car in '11 instead of 2 motor rebuilds. The 400 now is no slouch on the road, plenty of HP and Torque, getting around 22 on the road at 70.

4. I had a ''89 convertible for 7 years the same time I had the '76, buying the '89 already resto-modded with a crate 383 SBC, 4L60E AOD trans, Ford 9" rear end, air shocks, 18" and 20" torque thrust wheels. 305 owners, I think the 383 crate is a great drop in answer to upgrade the power in your Avanti. It would go in with little or no modification that an LS likely would need. I do understand a desire to keep the original power plant in the car, a problem I wrestled with in my '76.  We also need to consider the originality tag doesn't mean much on any Avanti after Studebaker stopped production.